نتایج جستجو برای: 2 substituted diols
تعداد نتایج: 2551101 فیلتر نتایج به سال:
Peculiarities in the physical properties of hydroxylic compounds result essentially from the molecular ordering due to hydrogen bond formation. In case of diols, which are among the most self-associated liquids, the structure of the intermolecular entities depends mainly on the mutual position of OH groups within the hydrocarbon chain of the molecule. Diols are widely used in industry, mainly b...
A gold(I)-catalyzed enantioselective desymmetrization of 1,3-diols was achieved by intramolecular hydroalkoxylation of allenes. The catalyst system 3-F-dppe(AuCl)2/(R)-C8-TRIPAg proved to be specifically efficient to promote the desymmetrizing cyclization of 2-aryl-1,3-diols, which have proven challenging substrates in previous reports. Multisubstituted tetrahydrofurans were prepared in good yi...
The regio- and chemoselective oxidation of unprotected vicinal polyols with [(neocuproine)Pd(OAc)]2(OTf)2 (1) (neocuproine = 2,9-dimethyl-1,10-phenanthroline) occurs readily under mild reaction conditions to generate α-hydroxy ketones. The oxidation of vicinal diols is both faster and more selective than the oxidation of primary and secondary alcohols; vicinal 1,2-diols are oxidized selectively...
Aromatic diols containing bis (azo) and bis (o-nitrobenzyl) chromophores viz., (4hydroxyphenylazo)-2,2/-dinitrodiphenylmethane, 4-hydroxy-3-methylphenylazo-4/-hydroxyphenylazo-2,2/-dinitrodiphenyl methane and bis (4-hydroxy-3-methylphenylazo)-2-dinitrodiphenyl methane were synthesized from 4,4-diamino-2,2/-dinitrodiphenylmethane and phenol/0-cresol. As a result of photolysis, the azo group of t...
At 90-120 °C, in the presence of methylcarbonate and bicarbonate methyltrioctylphosphonium salts as catalysts ([P8881][A]; [A] = MeOCO2 and HOCO2), the transesterification of non-toxic dimethyl- and diethyl-carbonate (DMC and DEC, respectively) with 1,X-diols (2 ≤ X ≤ 6) proceeds towards the formation of cyclic and linear products. In particular, 1,2-propanediol and ethylene glycol afford propy...
A library of pinane-based 2-amino-1,3-diols was synthesised in a stereoselective manner. Isopinocarveol prepared from (?)-?-pinene converted into condensed oxazolidin-2-one two steps by carbamate formation followed aminohydroxylation process. The relative stereochemistry the pinane-fused determined 2D NMR and X-ray spectroscopic techniques. regioisomeric spiro-oxazolidin-2-one similar way start...
Short chain diols (propanediols, butanediols, pentanediols) have been widely used in bulk and fine chemical industries as fuels, solvents, polymer monomers and pharmaceutical precursors. The chemical production of short chain diols from fossil resources has been developed and optimized for decades. Consideration of the exhausting fossil resources and the increasing environment issues, the bio-b...
Background. Production of highly pure enantiomers of vicinal diols is desirable, but difficult to achieve. Enantiomerically pure diols and acyloins are valuable bulk chemicals, promising synthones and potential building blocks for chiral polymers. Enzymatic reduction of ketones is a useful technique for the synthesis of the desired enantiomeric alcohols. Here, we report on the characterization ...
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