Vicinal functionalization using a Carbocupration- Mukaiyama aldol reaction sequence Muller, A.J.; Jennings, M.P. Vicinal Functionalization of propionilate Esters via Tandem Catalytic Carbocupration-Mukaiyama Aldol Reaction sequence. Org. Lett. 2008, 10, 1649-1652 Vicinal funct Muller and collaborators reported a vicinal functionalization of α,β- acetylenic esters using a Carbocupration/ Mukaiyama aldol reaction sequence (as shown in fig above) carbocupration favors the formation of the Z- aldol.
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Because the process requires vicinal diols, periodate oxidation is often used to selectively label the 3′-termini of RNA (ribose has vicinal diols) instead of DNA as deoxyribose does not have vicinal diols. Periodic acid is also used in as an oxidising agent of moderate strength.
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In vicinal difunctionalization the proton is replaced by another electrophile.
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Sodium periodate can be used in solution to open saccharide rings between vicinal diols leaving two aldehyde groups. This process is often used in labeling saccharides with fluorescent molecules or other tags such as biotin. Because the process requires vicinal diols, periodate oxidation is often used to selectively label the 3′-ends of RNA (ribose has vicinal diols) instead of DNA as deoxyribose does not have vicinal diols. NaIO4 is used in organic chemistry to cleave diols to produce two aldehydes.
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TPAP is also used to cleave vicinal diols to form aldehydes.
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The Sharpless oxyamination (often known as Sharpless aminohydroxylation) is the chemical reaction that converts an alkene to a vicinal amino alcohol. The reaction is related to the Sharpless dihydroxylation, which converts alkenes to vicinal diols.Bodkin, J. A.; McLeod, M. D. J. Chem. Soc., Perkin Trans.
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The vicinal tramway arrived in 1887 and a local airfield was built after World War I.
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The vicinal tramway line going from Ninove to Brussels Ninoofsepoort starts operating on September 8 1887. It used metre-gauge rails and had its depot in Schepdaal. This depot became the national museum for the vicinal tramway on May 5 1962,Dr. J. H.E. Reeskamp. Trams.
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In 1H NMR spectroscopy, the coupling of two hydrogen atoms on adjacent carbon atoms is called vicinal coupling. The vicinal coupling constant is referred to as 3J because the hydrogen atoms couple through three bonds. Depending on the other substituents, the vicinal coupling constant assumes values between 0 and +20 Hz.D. H. Williams, I. Fleming: Strukturaufklärung in der organischen Chemie; Eine Einführung in die spektroskopischen Methoden, 6. überarbeitete Auflage, Georg Thieme Verlag, Stuttgart 1991, S. 105.
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The dependence of the vicinal coupling constant on the dihedral angle \\!\,\phi is described by the Karplus relation.
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Pinacol is a white solid organic compound. It is a diol that has hydroxyl groups (-OH) on vicinal carbon atoms.
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Museum entrance On 8 September 1887 the first vicinal tramway in Brabant, Schepdaal – Brussels Ninoofsepoort was opened. The depot of the line was located in Schepdaal. This depot was transformed into the National Museum of Vicinal Tramways in the late 60's. The museum was maintained by volunteers, and closed in 1998 for renovations.
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It functions by binding to vicinal diols. Presently, the reagent is used in the analysis of the molecular weight of cellulose samples.
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The epoxides react further with water, organic acid, or peroxy acid, to ultimately form vicinal diols. Because the natural fatty acid olefins have (Z)-configurations, the resulting vicinal diols have anti stereochemical configurations. Fatty acids with hydroxyl groups on their hydrophobic tails are rare in nature. Compare hydroxylated lecithin to castor oil, which has 3 hydroxylated fatty acid chains in it.
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In organic synthesis OsO4 is widely used to oxidize alkenes to the vicinal diols, adding two hydroxyl groups at the same side (syn addition). See reaction and mechanism above. This reaction has been made both catalytic (Upjohn dihydroxylation) and asymmetric (Sharpless asymmetric dihydroxylation). Osmium(VIII) oxide is also used in catalytic amounts in the Sharpless oxyamination to give vicinal amino-alcohols.
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In glycol cleavage, the C−C bond in a vicinal diol is cleaved with formation of ketone or aldehyde functional groups. See Diol oxidation.
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ArsD is a trans-acting repressor of the arsRDABC operon that confers resistance to arsenicals and antimonials in Escherichia coli. It possesses two-pairs of vicinal cysteine residues, Cys(12)-Cys(13) and Cys(112)-Cys(113), that potentially form separate binding sites for the metalloids that trigger dissociation of ArsD from the operon. However, as a homodimer it has four vicinal cysteine pairs. The ArsD family consists of several bacterial arsenical resistance operon trans-acting repressor ArsD proteins.
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Simple fluorinations of alkenes often produce complex mixtures of products. However, cofluorination in the presence of a nucleophile proceeds cleanly to give vicinal alkoxyfluorides.Lal, G. S. J. Org. Chem. 1993, 58, 2791.
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USSR (Engl. Transl.) 1982, 18, 1220. (8)File:SF4Scope3.png Fluorination opens epoxides to give either geminal or vicinal difluorides in most cases. Monoarylepoxides give geminal products with migration of the aryl group.
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The arsenic atom in PAO has a high affinity for the sulfur atom of thiols in organic compounds, in particular, forming stable complexes with vicinal cysteine residues in protein structures. This effect makes it useful for studying ligand–receptor binding This binding affinity also makes PAO useful for affinity chromatography by immobilizing it on a resin. It has a high selectivity for structures with vicinal cysteines rather than single cysteine residues or cystine (a disulfide-bridged pair of cysteine residues).
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It is a common glycone component of glycosides from many plants. Rhamnose is also a component of the outer cell membrane of acid-fast bacteria in the Mycobacterium genus, which includes the organism that causes tuberculosis. An interesting particularity of rhamnose is the absence of formaldehyde production when reacted with periodates in the vicinal diol cleavage reaction, that makes it very useful to remove excess periodate in glycerol or other vicinal diol analysis, that would otherwise give colored blank issues.
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Trams in the museum The Flemish Tram and Bus Museum (Dutch: Vlaams Tram- en Autobusmuseum, abbreviated as VlaTAM) is a museum of public transport that exhibits historical trams and buses. The museum is situated in the Berchem district of Antwerp, in the former tram shed of Groenenhoek. The museum is supported by transport company De Lijn. It mainly exhibits trams and buses of the Vicinal company, the city tram companies of Antwerp and Ghent, and the various subcontractors of Vicinal and De Lijn.
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The Sharpless oxyamination converts an alkene to a vicinal amino alcohol. A common source of the amido component of this reaction is chloramine-T.Bodkin, J. A.; McLeod, M. D. J. Chem. Soc., Perkin Trans.
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Atomic Terrace Low Angle Shadowing (ATLAS) is a surface science technique which enables the growth of planar nanowire or nanodot arrays using molecular beam epitaxy on a vicinal surface. ATLAS utilises the inherent step-and- terrace structure of the surface as a template for such nanostructures.F. Cuccureddu, V. Usov, S. Murphy, C. O. Coileain, I. V. Shvets, Planar nanowire arrays formed by atomic-terrace low-angle shadowing, Rev. Sci. Instrum. 79, 053907 (2008), The technique involves the low angle incidence of flux material on vicinal substrates.
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The Overman rearrangement (named after Larry Overman) is a Claisen rearrangement of allylic trichloroacetimidates to allylic trichloroacetamides. The Overman rearrangement The Overman rearrangement is applicable to the synthesis of vicinol diamino compounds from 1,2-vicinal allylic diols.
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Glycoluril can be synthesized by reacting two equivalents of urea with glyoxal. Likewise, using other vicinal carbonyl (or carbonyl hydrate) reactants give derivatives having various functional groups in place of the hydrogen atoms on the carbon chain.
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NMVB interurbans at Oostende, on the surviving Belgian Coast Tram line. In Belgium, a sprawling, nation-wide system of narrow-gauge Vicinal tramways have been built by the NMVB / SNCV to provide transport to smaller towns across the country. These lines were either electrically-operated or run with diesel tramcars, included numerous street- running sections, and inter-operated with local tram networks in the larger cities. At their peak in , the mileage of vicinal tramways - at 4,811 kilometres in 1945 - even exceeded that of the national railway network.
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Originally, the square had an imposing design, with statues and decoration with plants and intersected by the Leien and Turnhoutsebaan. However, due to its central position at the crossing of these two major axes, the square soon became a hub for public transport. Beginning in 1934, more and more vicinal trams of the NMVB started to have their terminus at the Victorieplaats. Gradually, the amount of space taken in by public transport rose, up until 1968 vicinal trams, later buses and city trams, operated by the MIVA, and after 1992 by De Lijn.
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Triphenylphosphine dichloride, Ph3PCl2, is a chlorinating agent widely used in organic chemistry. Applications include the conversion of alcohols and ethers to alkyl chlorides, the cleavage of epoxides to vicinal dichlorides and the chlorination of carboxylic acids to acyl chlorides.
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In the second step of the reaction, a water molecule is activated by the charge-relay His297-Glu153 pair, and undergoes nucleophilic attack on the Cγ of Asp129. This hydrolyzes the ester group, liberating the hydrolysis product as a vicinal diol.
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The Belgian Coast Tram near Ostend. In Belgium an extensive prewar system of tram-like local railways called Vicinal or Buurtspoorweg lines used to exist, which had a greater total route kilometre length than the main-line railway system. The only survivors of the Vicinal system are the Kusttram, the longest tram line in the world, which almost reaches France at one end of the line and the Netherlands at the other, and two short lines that form part of the Charleroi Pre-metro. Urban tram networks exist in Antwerp, Ghent and Brussels, and are gradually being extended.
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As a vicinal- diol, it can rearrange to pinacolone by the pinacol rearrangement, e.g. by heating with sulfuric acid: 550px Pinacol can be used with borane and boron trichloride to produce useful synthetic intermediates such as pinacolborane, bis(pinacolato)diboron, and pinacolchloroborane.
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A.72.3) and MerC (TC# 1.A.72.4). MerF has two vicinal pairs of cysteine residues which are involved in the transport of Hg(II) across the membrane and are exposed to the cytoplasm. Some members of the MerF family have been designated MerH.
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In Belgium an extensive system of tram-like local railways called vicinal or buurtspoor lines crossed the country in the first half of the 20th century, and had a greater route length than the main-line railway system. The only survivors of the vicinal/buurtspoor system are the Kusttram (covering almost the entire coast from France to the Netherlands, being the longest tram line in the world) and some sections of the Charleroi Pre-metro. Urban tram networks exist in Antwerp (the Antwerp Pre-metro), Ghent and Brussels (the Brussels trams), and are gradually being extended. The only rapid transit system in Belgium is the Brussels Metro.
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Vicinal difunctionalization reactions, most generally, lead to new bonds at two adjacent carbon atoms. Often this takes place in a stereocontrolled fashion, particularly if both bonds are formed simultaneously, as in the Diels-Alder reaction. Activated double bonds represent a useful handle for vicinal difunctionalization because they can act as both nucleophiles and electrophiles—one carbon is necessarily electron poor, and the other electron rich. In the presence of a nucleophile and an electrophile, then, the two carbons of a double bond can act as a "relay," mediating electron flow from the nucleophile to the electrophile with the formation of two, rather than the usual one, chemical bonds.
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A large number of examples of vicinal difunctionalization of unsaturated carbonyl compounds exist in the literature. In one example, the difunctionalization of unsaturated lactone 1 was employed en route to isostegane. This transformation was accomplished in one pot.Damon, R.E.; Schlessinger, R.H.; Blount, J. J. Org. Chem.
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Lipton, F.; Sorensen, M.; Sadler, C.; Shapiro, H. J. Organomet. Chem. 1980, 186, 155. Usually, vicinal difunctionalizations are carried out in one pot, without the intermediacy of a neutral protected enolate. However, in specific cases it may be necessary to protect the intermediate of β-addition.
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Reactions of type 4 are also called acyloin rearrangements. While similar to the pinacol rearrangement, the semipinacol rearrangement differs from the pinacol rearrangement in that the cation is not formed from a vicinal 1,2-diol. With diazoalcohols the reaction is known as the Tiffeneau–Demjanov rearrangement.
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The Milas dihydroxylation was introduced in 1930, and uses hydrogen peroxide as the stoichiometric oxidizing agent. Although the method can produce diols, overoxidation to the dicarbonyl compound has led to difficulties isolating the vicinal diol. Therefore, the Milas protocol has been replaced by the Upjohn and Sharpless asymmetric dihydroxylation.
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Dihydroxylation of alkene produces diol, and dihydroxylation of alkyne produces vicinal dicarbonyl. A stronger oxidizing agent, for example KMnO4 or ozone, will lead to oxidative cleavage. In this case, the π bond breakes with the σ bond, dividing the hydrocarbon molecule into two. Oxygen bonds with the remaining two π bonds separately.
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For instance in certain aldol adducts with 2,6-disubstituted aryl groups the molecular geometry has the vicinal hydrogen atoms in an antiperiplanar configuration both in a crystal lattice (X-ray diffraction) and in solution proton (NMR coupling constants) normally reserved for the most bulky groups i.d. both arenes:Effect of 2,6-Disubstituted Aryl Groups on Acyclic Conformation: Preference for an Antiperiplanar Orientation of the Geminal and Vicinal Hydrogens Paul R. Carlier, Yiqun Zhang, Carla Slebodnick, Michael M.-C. Lo, and Ian D. Williams J. Org. Chem.; 2006; 71(23) pp 8835 - 8841; (Article) Syn-pentane effect in aldol adducts The other contributing factor explaining this conformation is reduction in allylic strain by minimizing the dihedral angle between the arene double bond and the methine proton.
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IBX is notable for oxidizing vicinal diols (or glycols) to diketones without cleavage of the carbon-carbon bond, but oxidative cleavage of glycols to two aldehydes or ketones can occur when modified conditions are used (elevated temperatures or trifluoroacetic acid solvent). :Oxidative cleavage of vicinal diols The reaction mechanism for this glycol cleavage is based on initial formation of an adduct between 10-I-4 IBX and DMSO to a 12-I-5 intermediate 3 in which DMSO acts as a leaving group for incoming alcohol 4 to intermediate 5. One equivalent of water is split off forming 12-I-5 spirobicyclic periodinane 6 setting the stage for fragmentation to 7. With hydroxyl alpha protons present, oxidation to the acyloin competes.
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Yields are low for sterically hindered di- and trisubstituted epoxides. Epoxides substituted with an ester group give vicinal difluorides via an alkoxysulfur trifluoride intermediate.Yagupol'skii, M.; Golikov, I.; Alekseeva, A.; Aleksandrov, M. J. Org. Chem. USSR (Engl. Transl.) 1971, 7, 737. (9)File:SF4Scope4.png When amines are treated with SF4 and a base, iminosulfur difluorides result.
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Medium-sized rings (7–13 carbons) experience more strain energy than cyclohexane, due mostly to deviation from ideal vicinal angles, or Pitzer strain. Molecular machanics calculations indicate that transannular strain, also known as Prelog strain, does not play an essential role. Transannular reactions however, such as 1,5-shifts in cyclooctane substitution reactions, are well known.
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Protection: 2,2-dimethoxypropane and camphorsulfonic acid, and dichloromethane Deprotection: Hydrochloric acid, methanol, water, and ethyl ether Protection of the vicinal diol 2.4 allowed the remaining hydroxyl group in alcohol 2.5 to be selectively oxidized to give aldehyde 2.6. The acetonide was removed much later in the synthesis in preparation for the closure of ring D.
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Han-sur-Lesse Han-sur-Lesse (, in Walloon: Han-so-Lesse) is a Walloon village in the municipality of Rochefort, Namur Province in southeastern Belgium. It is famous for the exceptional caves carved under a nearby hill by the river Lesse, which tourists reach via a preserved remnant of the country's vicinal tramway system.
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In Belgium RAVeL, French for réseau autonome de voies lentesRAVeL - Glossaire at ravel.wallonie.be (autonomous network of slow ways), is a Walloon initiative aimed at creating a network of itineraries reserved for pedestrians, cyclists, horse riders and people with reduced mobility. The network makes use of towpaths on river banks and disused railway or vicinal tramway lines.
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Comte O'Donnell published a seminal work on the Code Vicinal, in 1836 . His biographers characterized him as energetic, and firm, yet without being rigorous, but rather flexible with the unknown. He undertook his frequently arduous duties with moderation and humanity, qualities of fine character, and his service amongst the notables of the Conseil d'État was marked as particularly distinguished.
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The short timescale of interconversion precludes the separation of conformational isomers in most cases. Atropisomers are conformational isomers which can be separated due to restricted rotation. Protein folding also generates stable conformational isomers which can be observed. The Karplus equation relates the dihedral angle of vicinal protons to their J-coupling constants as measured by NMR.
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The reaction is conducted in refluxing dioxane, at which temperature, the sodium is liquid. This reaction has poor yield which is a consequence of multiple product formation. In the case of (1,3), (1,4), (1,5), (1,6) dihalides, it leads to formation of cyclic products. In vicinal dihalides, it forms alkenes, whereas in geminal dihalides, it forms alkynes.
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To get around this last barrier to mobility, an experimental ramp was installed in 2009 at Parvis de St-Gilles/St-Gillis Voorplein. A PCC leaving Place Rogier/Rogierplein for South/Midi station, before the opening of the north–south premetro. The tram stop in the background was also used by the Vicinal, which had its terminal loop here.
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Intelectin-1, also known as omentin or intestinal lactoferrin receptor, is an intelectin encoded in humans by the ITLN1 gene. Intelectin-1 functions both as a receptor for bacterial arabinogalactans and for lactoferrin. Having conserved ligand binding site residues, both human and mouse intelectin-1 bind the exocyclic vicinal diol of carbohydrate ligands such as galactofuranose.
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Steroidogenesis, showing progesterone among the progestogens in yellow area. In mammals, progesterone, like all other steroid hormones, is synthesized from pregnenolone, which itself is derived from cholesterol. Cholesterol undergoes double oxidation to produce 22R-hydroxycholesterol and then 20α,22R-dihydroxycholesterol. This vicinal diol is then further oxidized with loss of the side chain starting at position C22 to produce pregnenolone.
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Alkenes add to OsO4 to give diolate species that hydrolyze to cis-diols. The net process is called dihydroxylation. This proceeds via a [3 + 2] cycloaddition reaction between the OsO4 and alkene to form an intermediate osmate ester which rapidly hydrolyses to yield the vicinal diol. As the oxygen atoms are added in a concerted step, the resulting stereochemistry is cis.
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2-aminoethyl-diphenylborinate 2-aminoethyl-diphenylborinate also known as 2-APB, inhibits transient receptor potential channels. This kind of inhibition is being researched to find treatments for prostate cancer. In particular TRPM7. 2-APB can work as a catalyst to add an alkyl group from an alkyl halide to a polyol or carbohydrate that contains a cis-vicinal diol to a precise position.
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Charleroi Prémétro West Station (MLC) Public transport is provided by TEC (Transport En Commun), the Walloon public transport service. The greater Charleroi region is served by bus lines and a light-rail Metro system, (Métro Léger de Charleroi). Part of the latter is famous for incorporating one of the few remnants of the Vicinal, the former Belgian national tramway network.
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The "Duppigheim–Kolbsheim" station was put into operation on 28 September 1864, by the Compagnie des chemins de fer de l'Est (Eastern Railway Company), when the latter began the operation of the vicinal railway n°1 from Strasbourg to Barr. As of 2014, it is a travellers station of local interest (category C: less than 100 000 travellers/year from 2010 to 2011).
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Allylic methyl and ethyl groups are close together. Allylic strain, or A1,3 strain is closely associated to syn-pentane strain. An example of allylic strain can be seen in the compound 2-pentene. It's possible for the ethyl substituent of the olefin to rotate such that the terminal methyl group is brought near to the vicinal methyl group of the olefin.
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21, 1898); page 524. The term mixed drive train came to be used at the turn of twentieth century. The Pieper system was applied to Belgian (Vicinal tramway) and French (Compagnie des Chemins de Fer de Grande Banlieue) railcars as early as 1911. La Nature, 1921 Bulletin de la société d'encouragement pour l'industrie nationale, 1924 The Thomas system, manufactured by Thomas Transmission Ltd.
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The Upjohn dihydroxylation is an organic reaction which converts an alkene to a cis vicinal diol. It was developed by V. VanRheenen, R. C. Kelly and D. Y. Cha of the Upjohn Company in 1976. It is a catalytic system using N-methylmorpholine N-oxide (NMO) as stoichiometric re-oxidant for the osmium tetroxide. It is superior to previous catalytic methods.
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Epoxide hydrolases represent a group of enzymes that convert various types of epoxides to vicinal diols. Several members of this group have this metabolic activity on fatty acid epoxides including microsomal epoxide hydrolase (i.e. epoxide hydrolase 1 or EH1), soluble epoxide hydrolase (i.e. epoxide hydrolase 2 or EH2), epoxide hydrolase 3 (EH3), epoxide hydrolase 4 (EH4), and leukotriene A4 hydrolase (see epoxide hydrolase).
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Multiple in vitro substrates for thioredoxin have been identified, including ribonuclease, choriogonadotropins, coagulation factors, glucocorticoid receptor, and insulin. Reduction of insulin is classically used as an activity test. Thioredoxins are characterized at the level of their amino acid sequence by the presence of two vicinal cysteines in a CXXC motif. These two cysteines are the key to the ability of thioredoxin to reduce other proteins.
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Diaboleite crystal from a slag occurrence in the Laurium District, Attica, Greece (size: less than 1 mm) Diaboleite is deep blue in color and pale blue in transmitted light. The mineral occurs as tabular crystals up to in size, as subparallel aggregates, or it has massive habit. Vicinal forms of the tabular crystals have a square or octagonal outline and rarely exhibit pyramidal hemihedralism.
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Bond forming reactions between carbon and nitrogen are the most widely used in dynamic covalent chemistry. They have been used more broadly in materials chemistry for molecular switches, covalent organic frameworks, and in self-sorting systems. Imine formation takes place between an aldehyde or ketone and a primary amine. Similarly, aminal formation takes place between an aldehyde or ketone and a vicinal secondary amine.
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Cyclic α,β-unsaturated ketones are the most commonly employed substrates for vicinal difunctionalization. They tend to be more reactive than acyclic analogues and undergo less direct addition than aldehydes. Amides and esters can be used to encourage conjugate addition in cases when direct addition may be competitive (as in the addition of organolithium compounds).Franck, W.; Bhat, V.; Subramanian, S. J. Am. Chem. Soc.
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Diacetyl (IUPAC systematic name: butanedione or butane-2,3-dione) is an organic compound with the chemical formula (CH3CO)2. It is a yellow or green liquid with an intensely buttery flavor. It is a vicinal diketone (two C=O groups, side-by-side) with the molecular formula C4H6O2. Diacetyl occurs naturally in alcoholic beverages and is added to some foods to impart its buttery flavor.
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Upjohn dihydroxylation was reported in 1973 and uses OsO4 as the active catalyst in the dihydroxylation procedure. It also employs N-Methylmorpholine N-oxide (NMO) as the stoichiometric oxidant to regenerate the osmium catalyst, allowing for catalytic amounts of osmium to be used. The Upjohn protocol yields high conversions to the vicinal diol and tolerates many substrates. However, the protocol cannot dihydroxylate tetrasubstituted alkenes.
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Since osmium tetroxide is expensive and toxic, other metals have been used to prepare vicinal diols from olefins. Another popular metal used in dihydroxylation is ruthenium. Although it is highly oxidative, ruthenium has been used because of its short reaction time and its cost-effectiveness. Typically, the ruthenium tetroxide is created in situ from ruthenium trichloride, and a secondary oxidant NaIO4 is used to regenerate the catalyst.
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Glycol cleavage is a specific type of organic chemistry oxidation. The carbon–carbon bond in a vicinal diol (glycol) is cleaved and instead the two oxygen atoms become double-bonded to their respective carbon atoms. Depending on the substitution pattern in the diol, these carbonyls can be either ketones or aldehydes. Glycol cleavage is an important reaction in the laboratory because it is useful for determining the structures of sugars.
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Some of the longest known and most widely used oxo compounds are oxidizing agents such as potassium permanganate (KMnO4) and osmium tetroxide (OsO4). Compounds such as these are widely used for converting alkenes to vicinal diols and alcohols to ketones or carboxylic acids. More selective or gentler oxidizing reagents include pyridinium chlorochromate (PCC) and pyridinium dichromate (PDC). Metal oxo species are capable of catalytic, including asymmetric oxidations of various types.
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This northern section is one of the last electrified roadside sections of tramway which remains in Belgium. From avenue de la Couture, a section of the former vicinal also allows to reach the lower part of Thuin on the banks of Sambre. In August 2010, a 3 km extension to Biesme-sous-Thuin has been inaugurated. It is established on the platform of the former SNCB line from Mons to Chimay.
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The Milas hydroxylation is an organic reaction converting an alkene to a vicinal diol, and was developed by Nicholas A. Milas in the 1930s. The cis- diol is formed by reaction of alkenes with hydrogen peroxide and either ultraviolet light or a catalytic osmium tetroxide, vanadium pentoxide, or chromium trioxide. 400px The reaction has been superseded in synthetic chemistry by the Upjohn dihydroxylation and later by the Sharpless asymmetric dihydroxylation.
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After World War II, as intercity transport shifted to cars and buses, the system was gradually shut down by the 1980s. Today, two surviving sections exist. The famous Belgian Coast Tram traverses the entire Belgian coastline and, at a length of 68 km, is the longest tram line in the world. The Charleroi Metro is a pre-metro network upgraded and developed from the dense vicinal tramway network around the city.
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Hydrogenolysis and vicinal reduction are the two known processes of this mechanism that have been identified. In both processes, the removed halogen substituents are released as anions. Reductive dehalogenation is catalyzed by reductive dehalogenases, which are membrane-associated enzymes. A number of not only membrane-associated but also cytoplasmic hydrogenases, in some cases as part of the protein complexes, are predicted to play roles in the dehalorespiration process.
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The three- membered bromonium ion 2 consisted of two carbon atoms and a bromine atom forms with a release of Br−. #Attacking of bromide ion #:The bromonium ion is opened by the attack of Br− from the back side. This yields the vicinal dibromide with an antiperiplanar configuration. When other nucleophiles such as water or alcohol are existing, these may attack 2 to give an alcohol or an ether.
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Polysaccharides with unprotected vicinal diols or amino sugars (where some hydroxyl groups are replaced with amines) give a positive periodic acid-Schiff stain (PAS). The list of polysaccharides that stain with PAS is long. Although mucins of epithelial origins stain with PAS, mucins of connective tissue origin have so many acidic substitutions that they do not have enough glycol or amino-alcohol groups left to react with PAS.
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In electrophilic halogenation the addition of elemental bromine or chlorine to alkenes yields vicinal dibromo- and dichloroalkanes (1,2-dihalides or ethylene dihalides), respectively. The decoloration of a solution of bromine in water is an analytical test for the presence of alkenes: :CH2=CH2 \+ Br2 → BrCH2–CH2Br Related reactions are also used as quantitative measures of unsaturation, expressed as the bromine number and iodine number of a compound or mixture.
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Like all periodates periodic acid can be used to cleave various 1,2-difunctional compounds. Most notably periodic acid will cleave vicinal diols into two aldehyde or ketone fragments (Malaprade reaction). 650px This can be useful in determining the structure of carbohydrates as periodic acid can be used to open saccharide rings. This process is often used in labeling saccharides with fluorescent molecules or other tags such as biotin.
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The metabolism of the tobacco smoke procarcinogen benzo[a]pyrene involves three distinct steps - the introduction of an epoxide group in the 7,8-position, its hydration to a vicinal diol and the introduction of an epoxide in the 9,10-position. In the first step, a cytochrome P450 1A1 (CYP1A1) catalysed oxidation produces several products including (+)-benzo[a]pyrene-7,8-epoxide. The enzyme epoxide hydrolase, then hydrates the epoxide ring to yield the vicinal diol (−)-benzo[a]pyrene-7,8-dihydrodiol, which is then oxidised by cytochrome P450 oxidase again forming the mutagen and carcinogen (+)-benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide. This diol epoxide covalently binds to DNA by a ring-opening to alkylate the nucleobase forming a distorted structure, as shown at right, with intercalation of a pyrene polycyclic aromatic hydrocarbon moiety between the base pairs favouring π-stacking; these distortions have been confirmed by X-ray crystallographic and nuclear magnetic resonance structure studies.
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Traditionally protein NMR spectroscopists have used vicinal J-coupling information and the Karplus relation to determine approximate backbone torsion angle constraints for phi and chi-1 angles. However, several studies in the early 1990s pointed out the strong relationship between 1H and 13C chemical shifts and torsion angles, especially with backbone phi and psi angles. Later a number of other papers pointed out additional chemical shift relationships with chi-1 and even omega angles.
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Sharpless asymmetric dihydroxylation (also called the Sharpless bishydroxylation) is the chemical reaction of an alkene with osmium tetroxide in the presence of a chiral quinine ligand to form a vicinal diol. The reaction has been applied to alkenes of virtually every substitution, often high enantioselectivities are realized. Asymmetric dihydroxylation reactions are also highly site selective, providing products derived from reaction of the most electron-rich double bond in the substrate. The Sharpless dihydroxylation.
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Halohydrin dehalogenases mechanistically cleaves the carbon-halogen bond through the formation of an epoxide from a vicinal hydroxyl group. The substrate binds to the active site through hydrogen bonding that is coordinated by Ser132 and the deprotonated form of Tyr145. Failure to deprotonate Tyr145 by the Arg149 residue results in destabilization of the interaction between the enzyme and substrate resulting in reduced biological activity. The oxygen in Tyr145 deprotonates the hydroxyl group of the substrate.
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SNCV/NMVB was broken up in 1991 into De Lijn (for Flanders) and TEC (for Wallonia), both companies were now primarily operating buses. De Lijn inherited the tram systems in Ghent and Antwerp (including the Pre- metro), operated previously by local companies MIVG and MIVA respectively, and the coastal tramway. TEC operates the Charleroi Pre-metro, which includes sections of Vicinal track. STIB/MIVB operates the Brussels Metro, tram and bus network.
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It was initially believed that the barrier to rotation was due to steric interactions between vicinal hydrogens, but the Van der Waals radius of hydrogen is too small for this to be the case. Recent research has shown that the staggered conformation may be more stable due to a hyperconjugative effect. Rotation away from the staggered conformation interrupts this stabilizing force. More complex molecules, such as butane, have more than one possible staggered conformation.
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This Pull–push reactivity is important for understanding reactions mediated by π–acids. Complexation of the alkyne to the metal fragment depletes electron density in the bond (‘pull’), in concert with the ability of the metal to back donate (“push”) arouses the observed consecutive electrophilic and nucleophilic character to the vicinal carbon atoms of the alkyne (figure 7). center Metallacycle intermediates (19) are the result of the simultaneous complexation and activation of both partners.
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Vicinal difunctionalization refers to a chemical reaction involving transformations at two adjacent centers (most commonly carbons). This transformation can be accomplished in α,β-unsaturated carbonyl compounds via the conjugate addition of a nucleophile to the β-position followed by trapping of the resulting enolate with an electrophile at the α-position. When the nucleophile is an enolate and the electrophile a proton, the reaction is called Michael addition.Chapdelaine, M. J.; Hulce, M. Org. React.
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Arsenic, especially +3 As, binds to single, but with higher affinity to vicinal sulfhydryl groups, thus reacts with a variety of proteins and inhibits their activity. It was also proposed that binding of arsenite at nonessential sites might contribute to detoxification. Arsenite inhibits members of the disulfide oxidoreductase family like glutathione reductase and thioredoxin reductase. The remaining unbound arsenic (≤ 10%) accumulates in cells, which over time may lead to skin, bladder, kidney, liver, lung, and prostate cancers.
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Their unique feature is that they are capable of forming reversible covalent complexes with sugars, amino acids, hydroxamic acids, etc. (molecules with vicinal, (1,2) or occasionally (1,3) substituted Lewis base donors (alcohol, amine, carboxylate)). The pKa of a boronic acid is ~9, but they can form tetrahedral boronate complexes with pKa ~7. They are occasionally used in the area of molecular recognition to bind to saccharides for fluorescent detection or selective transport of saccharides across membranes.
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Tram services were not restored to normality until 1925. During the war there was poor maintenance, many horses were requisitioned and tram equipment was used for military purposes. On 1 January 1928, the TB and CFE networks merged, leaving only the TB and the vicinal/buurtspoor network in operation. The CFE was known for its 'chocolate bars' so named because of their dark brown livery (several examples can still be admired in the Brussels tram museum).
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Vicinal substrates are composed of atomic terraces separated by atomic steps. The ATLAS technique allows for the fabrication of well defined planar arrays of plasmonic nanostructures, of dimensions unachievable by lithography. A collimated beam of atoms or molecules is evaporated at an oblique angle to the substrate. This causes the steps to "shadow" the beam, and the molecules to be adsorbed only on the exposed parts of the steps in direct line of sight of the evaporator.
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In effect, the disulfide bond is transferred from the protein to the reagent in two steps, both thiol–disulfide exchange reactions. The in vivo oxidation and reduction of protein disulfide bonds by thiol–disulfide exchange is facilitated by a protein called thioredoxin. This small protein, essential in all known organisms, contains two cysteine amino acid residues in a vicinal arrangement (i.e., next to each other), which allows it to form an internal disulfide bond, or disulfide bonds with other proteins.
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The first step in the reaction mechanism is one-electron reduction of the carbonyl group by a reducing agent such as magnesium to a ketyl radical anion species. Two ketyl groups react in a coupling reaction yielding a vicinal diol with both hydroxyl groups deprotonated. Addition of water or another proton donor gives the diol. With magnesium as an electron donor, the initial reaction product is a 5-membered cyclic compound with the two oxygen atoms coordinated to the oxidized Mg2+ ion.
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Deoxydehydration (DODH) is a chemical reaction for removing two adjacent hydroxyl groups in a vicinal diol to form an alkene. In contrast to hydrodeoxygenation which uses hydrogen as a reductant, deoxydehydration is able to use a variety of other reductants such as alcohols and organic phosphines. In research, the most common homogeneous catalysts for this reaction use rhenium. Recently, research has focused on the use of vanadium heterogeneous catalysts for deoxydehydration, such as the conversion of 2,3-butanediol to butene.
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CH2 region (CDCl3, 300 MHz); starred peaks are from impurities Magnetic inequivalence may occur with H2C-CH2 fragments that are subdivided into two groups of two in either geminal relationships via a mirror plane along the C-C bond, i.e. HAHA′C-CHBHB′, or in vicinal relationships via a mirror plane bisecting the C-C bond, i.e. in HAHBC-CHA′HB′,Note that HAHBC-CHA′HB′ presents a mirror-related pair of diastereotopic hydrogens. Indeed, molecules with diastereotopic nuclei frequently show magnetic inequivalence.
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Since the 19th century, goods have been carried on rail vehicles through the streets, often near docks and steelworks, for example the Weymouth Harbour Tramway in Weymouth, Dorset. Belgian vicinal tramway routes were used to haul agricultural produce, timber, and coal from Blégny colliery while several of the US interurbans carried freight. In Australia, three different "Freight Cars" operated in Melbourne between 1927 and 1977"Destination City. Electric Rolling Stock of the Melbourne & Metropolitan Tramways Board", various editions, Australian Electric Traction Association, Melbourne.
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A halogen addition reaction is a simple organic reaction where a halogen molecule is added to the carbon–carbon double bond of an alkene functional group.Organic chemistry 4th Ed. Morrison & Boyd The general chemical formula of the halogen addition reaction is: :C=C + X2 → X−C−C−X (X represents the halogens bromine or chlorine, and in this case, a solvent could be CH2Cl2 or CCl4). The product is a vicinal dihalide. This type of reaction is a halogenation and an electrophilic addition.
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The Arboretum du parc de Rouelles, also known as the Arboretum des Ardennes, is an arboretum located within the Parc de Rouelles (over 150 hectares) on the Chemin Vicinal 3, south of Montivilliers, north of Le Havre, Seine-Maritime, Normandy, France. Long ago, the park was a medieval property of Pays de Caux with castle, park, farm, and forest. Most buildings were destroyed by bombardment in 1944, but a fine dovecote remains (dating to 1631). Today's park was created from 1980–1993.
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After the war, several Mack military trucks were purchased as surplus by European owners. In Belgium, the ministry of provision bought 380 Mack NR in order to compensate a truck shortage and the destruction of railways during the war. When the railroads improved, at least 50 Mack NR4D were rebuilt as cab-over buses for the National Vicinal tramway company (SNCV/NMVB) or private contractors. In other countries, surplus Mack NR trucks were also fitted with various bus, truck or van bodies.
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In extreme cases the periodate may be exchanged for lead tetraacetate which reacts in a similar manner and is soluble in organic solvents (Criegee oxidation). 650px Periodate cleavage is often utilized in molecular biochemistry for the purposes of modifying saccharide rings, as many five- and six-membered sugars have vicinal diols. Historically it was also used to determine the structure of monosaccharides. Periodate cleavage may be performed on an industrial scale to form dialdehyde starch which has uses in paper production.
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The superscript "3" indicates that a 1H atom is coupled to another 1H atom three bonds away, via H-C-C-H bonds. (Such hydrogens bonded to neighbouring carbon atoms are termed vicinal). The magnitude of these couplings are generally smallest when the torsion angle is close to 90° and largest at angles of 0 and 180°. This relationship between local geometry and coupling constant is of great value throughout nuclear magnetic resonance spectroscopy and is particularly valuable for determining backbone torsion angles in protein NMR studies.
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Since the π bondings will make cis/trans isomers, the unsaturated hydrocarbon isomers will appear differently due to different J-coupling effect. Cis vicinal hydrogens will have coupling constants in the range of 6–14 Hz, whereas the trans will have coupling constants of 11–18 Hz. In 13C NMR spectroscopy, compared to the saturated hydrocarbons, the double and triple bonds also deshiled the carbons, making them have low field shift. C=C double bonds usually have chemical shift of about 100–170 ppm.
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The "Dachstein–Altorf" station is put in operation on September 28, 1864 Gare d'Obernai : Historique by the Compagnie des chemins de fer de l'Est, when the latter began the operation of the vicinal railway n°1 bis between Strasbourg and Barr. Jacques Baquol, "Chemins de fer vicinaux", in L'Alsace ancienne et moderne ou dictionnaire du Haut et du Bas-Rhin, 1865, p. 373 As of 2014, it is a travellers station of local interest (category C: less than 100 000 travellers/year from 2010 to 2011).
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EH1, EH2, and EH3 have been shown to have such activity in that they add water to epoxides of unsaturated fatty acids to form vicinal cis (see cis-trans isomerism) products; the activity of EH4 has not been reported. The former three EH's differ in subcellular location, tissue expression patterns, substrate preferences, and thereby functions. These functions include limiting the biologically actions of certain fatty acid epoxides, increasing the toxicity of other fatty acid epoxides, and contributing to the metabolism of drugs and other xenobiotics.
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Hepoxilin-epoxide hydrolase coverts the epoxide residue in hepoxilins A3 and B3 to Vicinal (chemistry) diols as exemplified in the following enzyme reaction for the metabolism of hepoxilin A3 to trioxilin A3: 8-hydroxy-11S,12Sepoxy-(5Z,8Z,14Z)-eicosatrienoic acid + H2O \rightleftharpoons 8,11,12-trihydroxy-(5Z,9E,14Z)-eicosatrienoic acid The substrates of this enzyme are 8-hydroxy-11S,12Sepoxy-(5Z,8Z,14Z)-eicosatrienoic acid, i.e. hepoxilin A3 and H2O, whereas its product is 8,11,12-trihydroxy-(5Z,9E,14Z)-eicosatrienoic acid, i.e. the triol, trioxilin A3.
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The Ei mechanism (Elimination Internal/Intramolecular), also known as a thermal syn elimination or a pericyclic syn elimination, in organic chemistry is a special type of elimination reaction in which two vicinal substituents on an alkane framework leave simultaneously via a cyclic transition state to form an alkene in a syn elimination. This type of elimination is unique because it is thermally activated and does not require additional reagents unlike regular eliminations which require an acid or base, or would in many cases involve charged intermediates. This reaction mechanism is often found in pyrolysis.
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The bridge is situated in a rural area harmoniously implanted within the Peneda-Gerês National Park. It is erected northwest of the winter pasturelands of Cainheiras, over the river Cainheiras, at about above cultivatable and forested lands. It is located some from the chapel of Senhora da Boavista and from the chapel of Senhora de Anamão. The bridge of Cainheiras is part of a network of vicinal roads south and east of Castro Laboreiro, in addition to the Minhoto-Galacia regional roadways that connected Castro Laboreiro with Melgaço, Arcos de Valdevez and Bande.
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The Pinacol coupling reactionA pinacol coupling reaction is an organic reaction in which a carbon–carbon bond is formed between the carbonyl groups of an aldehyde or a ketone in presence of an electron donor in a free radical process. The reaction product is a vicinal diol. The reaction is named after pinacol (also known as 2,3-dimethyl-2,3-butanediol or tetramethylethylene glycol), which is the product of this reaction when done with acetone as reagent. The reaction is usually a homocoupling but intramolecular cross- coupling reactions are also possible.
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SF4's reactivity with carbonyl compounds is not enhanced in the presence of HF. Generally, only relatively acidic alcohols can be fluorinated efficiently with SF4, although amino alcohols appear to be an exception to this rule. (5)File:SF4Scope1.png When vicinal diols are combined with SF4, difluorination occurs with inversion of configuration at one of the alcohols. This was demonstrated in the synthesis of meso-difluorosuccinate from (L)-tartrate and the synthesis of (D)- and (L)-difluorosuccinate from meso- tartrate.Bell, M.; Hudlicky, M. J. Fluorine Chem. 1980, 15, 191. (6)File:SF4Scope2.
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Map of Belgium, its districts and major cities Legislation allowing the construction of rural tramways was passed in 1875, followed by a new law in 1885. The result was the creation of the national Vicinal tramway company – Nationale Maatschappij van Buurtspoorwegen (NMVB) in Dutch, Société nationale des chemins de fer vicinaux (SNCV) in French. The majority of lines were , although until 1921 many in the Antwerp area were gauge, later re-gauged. Many lines were built alongside roads, and carried considerable quantities of freight (especially timber and agricultural produce) as well as passengers.
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Alkenes reliably add bromine without catalysis to give the vicinal dibromides: :RCH=CH2 \+ Br2 → RCHBrCH2Br Aromatic compounds undergo bromination simultaneously with evolution of hydrogen bromide. Catalysts such as AlBr3 or FeBr3 are needed for the reaction to happen on aromatic rings. Chlorine-based catalysts (FeCl3, AlCl3) could be used, but yield would drop slightly as dihalogens(BrCl) could form. The reaction details following the usual patterns of electrophilic aromatic substitution: :RC6H5 \+ Br2 → RC6H4Br + HBr A prominent application of this reaction is the production of tetrabromobisphenol-A from bisphenol-A.
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When used in this fashion, the ruthenium(VIII) oxide is used in catalytic amounts and regenerated by the addition of sodium periodate to ruthenium(III) chloride and a solvent mixture of acetonitrile, water and carbon tetrachloride. RuO4 readily cleaves double bonds to yield carbonyl products, in a manner similar to ozonolysis. OsO4, a more familiar oxidant that is structurally similar to RuO4, does not cleave double bonds, instead producing vicinal diol products. However, with short reaction times and carefully controlled conditions, RuO4 can also be used for dihydroxylation.
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1973, 73 (17), 291-297 Most the reported transformations affect directly the iminopyrane cycle, and the iminogroup is the main target for nucleophilic and electrophilic attacks in many cases. However furthermore the iminogroup these compounds can contain other functional groups, which can participate in such interactions. Thus, vicinal arrangement of the imino and amide nucleophilic groups in 2-iminocoumarin-3-(thio)carboxoamides 4, 5 produces great opportunity to utilize these compounds as building blocks to construct different heterocyclic systems. Iminocoumarins can be formed by a variation of the Knoevenagel condensation by reaction of salicylaldehyde with substituted acetonitriles.
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The Criegee oxidation is a glycol cleavage reaction in which vicinal diols are oxidized to form ketones and aldehydes using lead tetraacetate. It is analogous to the Malaprade reaction, but uses a milder oxidant. This oxidation was discovered by Rudolf Criegee and coworkers and first reported in 1931 using ethylene glycol as the substrate. center The rate of the reaction is highly dependent on the relative geometric position of the two hydroxyl groups, so much so that diols that are cis on certain rings can be reacted selectively as opposed to those that are trans on them.
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The stoichiometry of the reaction is sensitive to conditions. This reaction and the ozonolysis can be used to determine the position of a double bond in an unknown alkene. The oxidation can be stopped at the vicinal diol rather than full cleavage of the alkene by using osmium tetroxide or other oxidants: :R'CH=CR2 \+ 1/2 O2 \+ H2O → R'CH(OH)-C(OH)R2 This reaction is called dihydroxylation. In the presence of an appropriate photosensitiser, such as methylene blue and light, alkenes can undergo reaction with reactive oxygen species generated by the photosensitiser, such as hydroxyl radicals, singlet oxygen or superoxide ion.
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Because of the railroad connection many rich people from Antwerp decided to build villas in the municipality. The local railways reached Kapellen railway station on July 31, 1927 and the tram was extended to the border of Putte on December 1, 1928.Rail Atlas Vicinal, Uitgever: Rail memories. Door Stefan Justens & Dick van der Spek The level crossing of the tram and the railroad was there for just short period of time. On March 1, 1934 the railway connection between Hoevenen and Kapellen is opened and from February 1, 1938 forward trams between Antwerp and Putte rode through Hoevenen.
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The amino acid residues in the structural calcium site are conserved among intelectins, thus it is likely that most, if not all, intelectins have two structural calcium ions. In the ligand binding site of XEEL and hIntL-1, the exocyclic vicinal diol of the carbohydrate ligand directly coordinates to the calcium ion. There are large variations in the ligand binding site residues among intelectin homologs suggesting that the intelectin family may have broad ligand specificities and biological functions. As there is no intelectin numbering conventions in different organisms, one should not assume functional homology based on the intelectin number.
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The caves have a constant temperature of and a high level of humidity. The largest room in the complex is called La Salle du Dôme (English: the Hall of the Dome); it is across with a vaulted ceiling that reaches . Although modern exploration of the complex began in 1771, the cave has been known to locals for much longer. Bronze Age relics have been found inside, indicating use from at least the 5th century BC. Access is only possible via a vintage streetcar, a remnant of the country's once extensive vicinal tramway system, which departs from the center of Han-sur-Lesse.
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Figure 1. Deposition at a shallow angle on a vicinal surface (a) deposition of nanostructures on the outer step edges; beam at an angle β along the "downhill" direction, (b) substrate is rotated by 180° and the beam is directed in the "uphill" direction. Figure 1(a) shows a schematic of the deposition in the "downhill" direction, that is, from an outer step edge to a lower terrace. The deposition angle β between the beam and surface is small (1°-3°) so that some areas of the terraces are exposed to the beam, and others are geometrically shadowed.
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The capabilities of the system were first tested by growing arrays of 10-30 nm wide metallic nanowires on two types of vicinal substrates, step-bunched Si(111) and α-Al2O3(0001). Deposition of Au and Ag onto these substrates yields arrays of wires with a width and height of 15 nm and 2 nm, and separated by approximately 30 nm. Since its introduction in 2008, ATLAS has been demonstrated as a simple technique to produce nanowires of a variety of materials down to a width of 15 nm and thickness of 2 nm, on several stepped substrates.
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The deprotonated oxygen then acts as a nucleophile and performs a Sn2 reaction on the vicinal carbon that is bonded to the halogen; this releases a halogen ion and simultaneously forms an epoxide. Dehalogenases are also able to catalyze the ring-opening of the epoxide. The active site is large enough to accommodate a nucleophile which can perform a nucleophilic attack on the epoxide, opening the epoxide ring and adding a new functional group to the substrate. Overall mechanistic action of halohydrin dehalogenases In regards to the geometry of the product, both class A and B dehalogenases have a low selective preference for the (S)-epoxide isomer.
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HDDA-derived benzynes have also been shown to dehydrogenate saturated alkanes to form alkenes.Niu, D.; Willoughby, P. H.; Woods, B. P.; Baire, B.; Hoye, T. R. Nature, 2013, 501, 531 In the absence of external trapping reagents, the benzyne intermediate can abstract vicinal (chemistry) hydrogen atoms from a suitable donor, often the reaction solvent (such as tetrahydrofuran or cyclooctane). This desaturates the donor alkane, forming an alkene, and traps the benzyne to a dihydrobenzenoid product. Isotopic labelling and computational studies suggest that the double hydrogen transfer mechanism occurs by a concerted pathway and that the rate of reaction is highly dependent on the conformation of the alkane donor.
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In cells, EEQs are rapidly metabolized by the same enzyme that similarly metabolizes other epoxy fatty acids including the EETs viz., cytosolic soluble epoxide hydrolase [EC 3.2.2.10.] (also termed sEH or the EPHX2), to form their corresponding Vicinal (chemistry) diol dihydroxyeicosatetraenoic acids (diHETEs). The omega-3 fatty acid epoxides, EEQs and EPAs, appear to be preferred over EETs as substates for sEH. sEH converts 17,18-EEQ isomers to 17,18-dihydroxy-eicosatrienoic acid isomers (17,18-diHETEs), 14,15-EEQ isomers to 14,15-diHETE isomers, 11,12-EEQ isomers to 11,12-diHETE isomers, 8,9-EEQ isomers to 8,9-diHETE isomers, and 5,6-EEQ isomers to 5,6-diHETE isomers.
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Route 4 is one of the oldest tram routes in the city of Antwerp. It was originally built as a part of a vicinal tramway to Schelle and Boom, but was eventually shortened to the itinerary Groenplaats-Hoboken after the opening of railway line 52 In 1936, it was merged with route 3 into an itinerary Merksem- Central station-Groenplaats-South Station-Hoboken, because too many tram routes had their terminus at the Groenplaats at the time, leading to a chaotic situation. After the end of the Second World War, the route again became a separate line. In 1993, it was extended from the Groenplaats to the Sint- Pietersvliet to the North.
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5'-methylcytosine molecule with methyl group, added by a DNA methyltransferase, highlighted in red DNA methylation, a key component of genetic regulation, occurs primarily at the 5-carbon of the base cytosine, forming 5’methylcytosine (see left). Methylation is an epigenetic modification catalyzed by DNA methyltransferase enzymes, including DNMT1, DNMT2, and DNMT3. These enzymes use S-adenosylmethionine as a methyl donor and contain several highly conserved structural features between the three forms; these include the S-adenosylmethionine binding site, a vicinal proline-cysteine pair which forms a thiolate anion important for the reaction mechanism, and the cytosine substrate binding pocket. Many features of DNA methyltransferases are highly conserved throughout many classes of life, from bacteria to mammals.
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The Molsheim train station is put in operation on September 28, 1864 Christophe Lachenal : Gare SNCF d'Obernai : Historique by the Compagnie des chemins de fer de l'Est (Eastern Railways Company), when the latter began the operation of the vicinal line n°1 bis from Strasbourg to Barr. Jacques Baquol, « Chemins de fer vicinaux », dans L'Alsace ancienne et moderne ou dictionnaire du Haut et du Bas-Rhin, 1865 p. 373 The former station is destroyed in 1993. La ligne Molsheim–Saverne As of 2014, the Molsheim station is a travellers station of regional interest belonging the category B, its frequentation being superior or equal to 100 000 travellers per year from 2010 to 2011).
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Although extracellular tTG is expected to be active due to the low concentration of guanine nucleotides and the high levels of calcium in the extracellular space, evidence has shown that extracellular tTG is mostly inactive. Recent studies suggest that extracellular tTG is kept inactive by the formation of a disulfide bond between two vicinal cysteine residues, namely Cys 370 and Cys 371. When this disulfide bond forms, the enzyme remains in an open confirmation but becomes catalytically inactive. The, oxidation/reduction of the disulfide bond serves as a third allosteric regulatory mechanism (along with GTP/GDP and Ca2+) for the activation of tTG. Thioredoxin-1 has been shown to activate extracellular tTG by reducing the disulfide bond.
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Periodic acid Periodic acid–Schiff (PAS) is a staining method used to detect polysaccharides such as glycogen, and mucosubstances such as glycoproteins, glycolipids and mucins in tissues. The reaction of periodic acid oxidizes the vicinal diols in these sugars, usually breaking up the bond between two adjacent carbons not involved in the glycosidic linkage or ring closure in the ring of the monosaccharide units that are parts of the long polysaccharides, and creating a pair of aldehydes at the two free tips of each broken monosaccharide ring. The oxidation condition has to be sufficiently regulated so as to not oxidize the aldehydes further. These aldehydes then react with the Schiff reagent to give a purple-magenta color.
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In cells, the EETs are rapidly metabolized by a cytosolic soluble epoxide hydrolase (sEH) which adds water (H2O) across the epoxide to form their corresponding Vicinal (chemistry) diol dihydroxyeicosatrienoic acids (diHETrEs or DHETs), i.e. sEH converts 14,15-ETE to 14,15-dihydroxy-eicosatrienoic acid (14,15-diHETrE), 11,12-ETE to 11,12-diHETrE, 8,9-ETE to 8,9-diHETrE, and 5,6-ETE to 5,6-diHETrE. The product diHETrEs, like their epoxy precursors, are enantiomer mixtures; for instance, sEH converts 14,15-ETE to a mixture of 14(S),15(R)-diHETrE and 14(R),15(S)-diHETrE. However, 5,6-EET is a relatively poor substrate for sEH and in cells is more rapidly metabolized by cyclooxygenase-2 to form 5,6-epoxy-prostaglandin F1α.
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Similar to EETs (see Epoxyeicosatrienoic acid), EDPs are rapidly metabolized in cells by a cytosolic soluble epoxide hydrolase (sEH, also termed Epoxide hydrolase 2 [EC 3.2.2.10.]) to form their corresponding Vicinal (chemistry) diol dihydroxyeicosapentaenoic acids. Thus, sEH converts 19,20-EDP to 19,10-dihdroxydocosapentaenoic acid (DPA), 16,17-EDP to 16,17-dihydroxy-DPA, 13,14-EDP to 13,14-dihydroxy-DPA, 10,11-EDP to 10,11-dihydroxy-DPA, and 7,8-EDP to 7,8-dihydroxy-EDP; 4,5-EDP is unstable and therefore generally not detected in cells. The dihydroxy-EDP products, like their epoxy precursors, are enantiomer mixtures; for instance, sEH converts 16,17-EDP to a mixture of 16(S),17(R)-dihydroxy-DPA and 16(R),1y(S)-dihydroxy-DPA.
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1, Plenum, New York, 1976 Only in highly polar solvents such as hexafluoroisopropanol (HFIP) of low nucleophilicity one can expect a nearly same uniform SN1-like mechanism. The solvolysis of several cyclopentyl and steroidal esters show that large solvolysis rates and differences between epimers can occur which surpass those of the 2-norbornyl system. In these cases a vicinal C–C or C–H bond can lead to significant delocalization of the positive charge, if these bonds are close to antiperiplanar to the leaving group, and the migration leads to a more stable tertiary carbocation. Nonclassical charge delocalization in the transition state of a 1,2-alkyl shiftThe reaction products in these cases always result from the migration of the neighbouring bond.
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In water, it behaves as a Lewis acid, accepting the electron pair of a hydroxyl ion produced by the water autoprotolysis. B(OH)3 is acidic because of its reaction with OH− from water, forming the tetrahydroxyborate complex [B(OH)4]− and releasing the corresponding proton left by the water autoprotolysis: : B(OH)3 \+ 2 H2O ⇌ [B(OH)4]− \+ [H3O]+ (pKa = 8.98)Ingri N. (1962) Acta Chem. Scand., 16, 439. In the presence of cis-vicinal diols, such as mannitol, sorbitol, glucose and glycerol, the acidity of the boric acid solution is increased, and the pKa can be lowered to about 4 if enough mannitol is added.. With different mannitol concentrations, the pK of B(OH)3 extends on 5 orders of magnitude (from 9 to 4).
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Benson was born on September 24, 1917, in Modesto, California, the son of a rural physician of Swedish immigrant stock.. He studied as an undergraduate and masters student at the University of California, Berkeley, where he learned optics from Luis Alvarez and worked in the chemistry lab of Glenn T. Seaborg. In 1942, he received his Ph.D. from the California Institute of Technology;. at Caltech, he worked under the supervision of Carl Niemann, conducting experiments on the fluorination of thyroxine; his later thesis work concerned "periodate and lead tetraacetate degradation of its vicinal amino glycol". At that time he also became a conscientious objector to the war in Europe, a political position that caused difficulties for him when he moved back to Berkeley following his graduation.
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Oxidation of an alkene with osmium tetroxide (0.06 eq.) and NMO (1.2 eq.)in acetone/water 5:1 RT 12 hrs.Preparation of 3H-Pyrrolo[2,3-c]isoquinolines and 3H-Pyrrolo[2,3-c][2,6]- and 3H-Pyrrolo[2,3-c][1,7]-naphthyridines U. Narasimha Rao, Xuemei Han and Edward R. Biehl Arkivoc 2002 (x) 61-66 Online Article NMO, as an N-oxide, is an oxidant. It is generally used in stoichiometric amounts as a secondary oxidant (a cooxidant) to regenerate a primary (catalytic) oxidant after the latter has been reduced by the substrate. Vicinal syn-dihydroxylation reactions for example, would, in theory, require stoichiometric amounts of toxic, volatile and expensive osmium tetroxide, but if continuously regenerated with NMO, the amount required can be reduced to catalytic quantities.
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Simultaneously with the shift, a pi bond forms from the oxygen to carbon, assisting in driving the migrating group off its position. The result is a ketone or aldehyde.Strategic applications of named reactions in organic synthesis: background and detailed mechanisms László Kürti, Barbara Czakó 2005 In another definition all semipinacol rearrangements "share a common reactive species in which an electrophilic carbon center, including but not limited to carbocations, is vicinal to an oxygen-containing carbon and can drive the 1,2-migration of a C–C or C–H bond to terminate the process, generating a carbonyl group ".Semipinacol Rearrangement in Natural Product Synthesis Zhen-Lei Song, Chun- An Fan, Yong-Qiang Tu Chemical Reviews The rearrangement reaction can be classified into 4 types.
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In the best known of these metabolic pathways, cellular CYP epoxygenases metabolize the 20-carbon straight-chain omega-6 fatty acid, arachidonic acid, to epoxyeicosatrienoic acids (EETs); another CYP epoxygenase pathway metabolizes the 20-carbon omega-3 fatty acid, eicosapentaenoic acid (EPA), to epoxyeicosatetraenoic acids (EEQs). CYP epoxygenases similarly convert various other PUFAs to epoxides (see epoxygenase) These epoxide metabolites have a variety of activities. However, essentially all of them are rapidly converted to their corresponding, but in general far less active, Vicinal (chemistry) dihydroxy fatty acids by ubiquitous cellular Soluble epoxide hydrolase (sEH; also termed Epoxide hydrolase 2). Consequently, these epoxides, including EDPs, operate as short-lived signaling agents that regulate the function of their parent or nearby cells.
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Including additional buffered trifluoroacetic acid in the mixture gives a vicinal hydroxy–trifluoroacetate structure instead of an epoxide, which can be converted to the diol by treatment with acidic methanol, such as in the following conversion of 1-dodecene to 1,2-dodecanediol. 600px In the case of an allyl alcohol compound with a proximate carbonyl functional group, the epoxide can undergo a ring- expansion reaction to form a dioxolane. The process below was used as part of the total synthesis of neosporol, a natural product: 700px The preparation of the isomeric compound sporol involved a similar dioxolane formation. In this case, the use of trifluoroperacetic acid derived from hydrogen peroxide, which therefore presumably contained traces of water, gave mostly a hemiacetal rather than the closed-ring dioxolane.
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RvEs are di- or tri- hydroxyl metabolites of EPA. To date, four RvEs have been described: RvE1 (5S,12R,18R-trihydroxy-EPA), 18S-Rv1 (5S,12R,18S-trihydroxy-EPA), RvE2 (5S,18R-dihydroxy-EPA), and RvE3 (17R,18R/S-dihydroxy-EPA). (Structures of the RvEs are further defined at Specialized proresolving mediators#EPA-derived Resolvins.) Resolvin Es are formed in manner similar to AT resolving Ts. COX-2 modified in activity by aspirin or atorvastatin or, alternatively, a microbial or possibly mammalian cytochrome P450 monoxygenase metabolizes EPA to its 18R-hydroperoxy derivative; this intermediate is then further metabolized by ALOX5 to a 5,6 epoxide which is hydrolyzed enzymatically or non-enzymatically to RvE1 and 18S-RvE1 or reduced to RvE2; alternatively the 18R-hydroperoxide is converted to the 17R,18S vicinal diol product, RvE3.
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In a biological context chlorine behaves similarly to other atoms in the halogen chemical series, and thus reductive dechlorination can be considered to fall within a somewhat broader class of biological reactions known as reductive dehalogenation reactions, in which the removal of a halogen substituent from an organic molecule occurs with a simultaneous addition of electrons to the molecule. This can be further subdivided into two types of reaction processes, the first of which, hydrogenolysis, is the replacement of the halogen atom with a hydrogen atom. The second, vicinal reduction (sometimes called, dihaloelimination), involves the removal of two halogen atoms that are adjacent on the same alkane or alkene molecule, leading to the formation of an additional carbon-carbon bond. Biological reductive dechlorination is often catalyzed by certain species of bacteria.
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Long-chain dicarboxylic acids containing vicinal dimethyl branching near the centre of the carbon chain have been discovered in the genus Butyrivibrio, bacteria which participate in the digestion of cellulose in the rumen. These fatty acids, named diabolic acids, have a chain length depending on the fatty acid used in the culture medium. The most abundant diabolic acid in Butyrivibrio had a 32-carbon chain length. Diabolic acids were also detected in the core lipids of the genus Thermotoga of the order Thermotogales, bacteria living in solfatara springs, deep-sea marine hydrothermal systems and high-temperature marine and continental oil fields. It was shown that about 10% of their lipid fraction were symmetrical C30 to C34 diabolic acids. The C30 (13,14-dimethyloctacosanedioic acid) and C32 (15,16-dimethyltriacontanedioic acid) diabolic acids have been described in Thermotoga maritima.
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The first publication on vinylene carbonate described its Diels-Alder reaction using the example of its addition reaction with 2,3-dimethylbutadiene to a bicyclic carbonate and subsequent hydrolysis to cis-4,5-dihydroxy-1,2-cyclohexene: Cis-4,5-Dihydroxy-1,2-cyclohexen-Synthese When cyclopentadiene is used as the diene, the vicinal norbornene diol bicyclo[2.2.1]hept-5-ene-2,3-diol is formed after hydrolysis. The Swern oxidation to the 1,2-ketone bicyclo[2.2.1]hept-5-ene-2,3-dione proceeds (in the variant with trifluoroacetic anhydride instead of oxalyl chloride) with a yield of 73%. Norbornendion Under UV irradiation, ketones react with vinylene carbonate to form bicyclic exo-oxetanes: VC addition to ketones With phosphorus(V)sulfide, vinylene carbonate reacts to the corresponding vinylenethionocarbonate (2-thiono-1,3-dioxol-4-ene), which gives ketene in quantitative yield upon UV irradiation.
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Space-filling model of pyrene showing the planar structure Pyrene is a polycyclic aromatic hydrocarbon consisting of four benzene rings fused together in a planar aromatic arrangement which approximates a rhombus in shape. Benzo[a]pyrene is a derivative in which a fifth benzene ring has been fused to the pyrene system, and is a component of tobacco smoke which is a procarcinogen partly responsible for the carcinogenic and mutagenic effects of smoking. Benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide is a metabolite of benzo[a]pyrene formed by the introduction of vicinal hydroxyl and epoxide functional groups to the fifth benzene ring. These oxidations are stereoselective, producing the pair of enantiomers with the hydroxyl groups on opposite sides of the pyrene plane and with the epoxide on the same side as its adjacent hydroxyl group.
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In 1967 he was a member of the Belgian delegation of the International Theater Institute of Unesco in Warsaw and instrumental in the "discovery" of Jerzy Grotowsky, later universally recognized as a renewer of the art of the theatre. In 1970 Brulin directed Saboo, the first production of Théâtre Laboratoire Vicinal with Frédéruc Flamand (Plan K, Charleroi Danse now in Marseille) which caught the attention of Maurice Béjart In 1975 he founded The Theatre of the Third World, Tiedrie. Between 1975 and 1985 this company developed a multicultural repertory of African and Asian plays such as Kapai- kapai (12O performances), Ba Anansi, Charkawa Gilgamesh, The Prostitutes of Jakarta of Rendra and the Jero plays of Wole Soyenka. He worked intensively as a pioneer with African and Asian actors since Potopot was published in Théâtre de Belgique and in the early 1950s was staged with an actor of Sierra Leone.
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Vicinal diols can be produced via the Upjohn dihydroxylation or enantioselectively using Sharpless asymmetric dihydroxylation with enantiomeric excesses as high as 100%. Bromination of trans-stilbene produces predominantly meso-1,2-dibromo-1,2-diphenylethane (sometimes called meso-stilbene dibromide), in line with a mechanism involving a cyclic bromonium ion intermediate of a typical electrophilic bromine addition reaction; cis- stilbene yields a racemic mixture of the two enantiomers of 1,2-dibromo-1,2-diphenylethane in a non-polar solvent such as carbon tetrachloride, but the extent of production of the meso compound increases with solvent polarity, with a yield of 90% in nitromethane. The formation of small quantities of the two enantiomers of stilbene dibromide from the trans- isomer suggests that the bromonium ion intermediate exists in chemical equilibrium with a carbocation intermediate PhCHBr-C(H)Ph with a vacant p orbital vulnerable to nucleophilic attack from either face. The addition of bromide or tribromide salts restores much of the stereospecificity even in solvents with a dielectric constant above 35.
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In Brazil, toll roads are a recent institution, and were adopted mostly in non-federal highways. The state of São Paulo has the highest length of toll roads, which are exploited either by private companies which bought a concession from the state, or by a state owned company (see Highway system of São Paulo). In São Paulo there is also a statewide electronic collection system using a plastic transponder (e-tag) attached to the windscreen, named SemParar'. There is a growing trend towards tolling in all major highways of the country, but some resistance by the population is beginning to be felt, particularly due to some abuses which are being imposed, restricting the constitutional rights of coming and going (because the Brazilian highway system has very few non-tolled vicinal roads in parallel to highways) and making some trips an extremely expensive affair, as compared to average Brazilian earning power (in São Paulo, a 1,000 km round trip may cost upward of two hundreds Brazilian real in some roads, higher than petrol expenses).
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The cyanamide anion has the character of a pseudo chalcogen, cyanamide can therefore be regarded as analogue to water or hydrogen sulfide. A convenient method for the preparation of secondary amines which are not contaminated with primary or tertiary amines is the reaction of cyanamide with alkyl halides to N,N-dialkylcyanamides which can easily be hydrolyzed to dialkylamines and then decarboxylated. Cyanamide adds itself in the presence of N-bromosuccinimide to olefinic double bonds. The addition product is converted by bases to N-Cyanaziridine, cyclized in the presence of acids to imidazolines, which can be further reacted to vicinal diamines by alkaline cleavage.. Cyanamide is also a versatile synthetic building block for heterocycles: it forms 2-aminobenzimidazole with 1,2-diaminobenzene. and it forms with the readily available cyclic enamine 4-(1-cyclohexenyl)morpholine and with elemental sulfur a 2-aminothiazole in good yields.. Sodium dicyanamide is available in good yield and high purity from cyanamid and cyanogen chloride,Verfahren zur Herstellung von Natrium- Dicyanamid, veröffentlicht am 10.
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With polyols containing cis-vicinal diols, such as glycerol and mannitol, the acidity of the boric acid solution is increased. With different mannitol concentrations, the pK of B(OH)3 extends on five orders of magnitude (from 9 to 4): this exacerbed acidity of boric acid in the presence of mannitol is also sometimes referred as "mannitoboric acid". Greenwood and Earnshawn (1997) refer to a pK value of 5.15 while a pK value of 3.80 is also reported in Vogel's book. This is due to the formation of a boron-mannitol chelate, [B(C6H8O2(OH)4)2]−, also known as mannitoborate complex, according to the following complexation reaction releasing a proton: : ⇌ + 3 H2O + H+ :(pKa ranging from 4 to 9, depending on the mannitol concentration) This feature is used in analytical chemistry to determine the boron content in aqueous solution by potentiometric titration with a strong base, such as NaOH. Boric acid also dissolves in anhydrous sulfuric acid: :B(OH)3 \+ 6 H2SO4 → B(HSO4)4− \+ 2 HSO4− \+ 3 H3O+ Boric acid reacts with alcohols to form borate esters, B(OR)3 where R is alkyl or aryl.
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