نتایج جستجو برای: 2 substituted diols
تعداد نتایج: 2551101 فیلتر نتایج به سال:
Ruthenium(II) PNN complexes depolymerize many polyesters into diols and polycarbonates into glycols plus methanol via hydrogenation. Notably, polyesters with two methylene units between ester linkages depolymerize to carboxylic acids rather than diols. This methodology represents a new approach for producing useful chemicals from waste plastics.
We demonstrate the application of a multicatalyst to the oxidation of a broad variety of aldehydes and subsequent enantioselective esterification of the incipient acids with (±)-trans-cycloalkane-1,2-diols. This reaction operates well with a multicatalyst bearing two independent catalytic moieties that provide monoprotected 1,2-diols in one pot.
Reaction of substituted-aniline (8) with ethyl (l-methyl-5-nitroimidazole-2- carbonyl) acetate (9) gave 4-hydroxy-2-(l-methyl-5-nitro-2-imidazolyl)- substituted-quinolines (lo), which were converted to compound 11 with phosphorus oxychloride. Substituted-2-(l-methyl-5-nitro-2-imidazo1yl)-4.- methyl-(or phenyl-) quinolines (14) were prepared through the reaction of 2- acetyl-5-nitro-1-methy...
Novel 3-acetyl-2-aminothiophenes were prepared from cyanoacetone and 1,4-dithianyl-2,5-diols using a modified Gewald reaction. The syntheses of the corresponding acetamides, as well as that of 3-acetyl-2-amino-5-nitrothiophene - an interesting building-block for thiophene azo dyes - are reported. Detailed spectroscopic investigations ((1)H-NMR, (13)C-NMR, MS, IR) of the obtained compounds are p...
1. Diacetates of the four possible racemates of 4',7-dimethoxyflavan-3,4-diol have been synthesized. 2. Comparison of their nuclear-magnetic-resonance spectra and the ionophoretic mobilities of the diols in borate buffer with those of the corresponding derivatives of guibourtacacidin shows that the natural 4',7-dihydroxyflavan-3,4-diol has a 2,3-cis-3,4-trans configuration, but is accompanied b...
The ACE1 and RAP1 genes from the avirulence signalling gene cluster of the rice blast fungus Magnaporthe oryzae were expressed in Aspergillus oryzae and M. oryzae itself. Expression of ACE1 alone produced a polyenyl pyrone (magnaporthepyrone), which is regioselectively epoxidised and hydrolysed to give different diols, 6 and 7, in the two host organisms. Analysis of the three introns present in...
Esterification reactions of some polyols and diols were investigated in the presence of SnO2 and nano-SnO2 and the results were compared with the catalyst-free conditions. High conversions were obtained for most of the reactions in the presence of SnO2 and nano-SnO2 which shows the high catalytic activity of SnO2 and nano-SnO2</sub...
The fact that IBX exhibits reactivity akin to DMP is demonstrated from the results observed with strained and sterically hindered syn 1,2-diols, which undergo oxidative cleavage via a 12-I-5 spirobicyclic periodinane. The use of TFA, a protonating solvent, promotes the formation of the 12-I-5 intermediate for 1,2-diols of all types (sec,sec, sec,tert and tert,tert), leading to efficient oxidati...
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