نتایج جستجو برای: primary alcohols
تعداد نتایج: 652515 فیلتر نتایج به سال:
An in situ approach involving a simple mix and shake method for testing the enantiopurity of primary, secondary and tertiary chiral amines and their derivatives, chiral amino alcohols, by (1)H-NMR spectroscopy is developed. The protocol involves the in situ formation of chiral ammonium borate salt from a mixture of C2 symmetric chiral BINOL, trialkoxyborane and chiral amines. The proposed conce...
A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor
We demonstrate the preparation and characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol entered the reactor as plugs but merged into an ...
The cationic ruthenium catalyst generated upon the acid-base reaction of H2Ru(CO)(PPh3)3 and 2,4,6-(2-Pr)3PhSO3H promotes the redox-triggered C-C coupling of 2-alkynes and primary alcohols to form (Z)-homoallylic alcohols with good to complete control of olefin geometry. Deuterium labeling studies, which reveal roughly equal isotopic compositions at the allylic and distal vinylic positions, alo...
In this work, we present a mild method for direct conversion of primary alcohols into carboxylic acids with the use of water as an oxygen source. Applying a ruthenium dihydrogen based dehydrogenation catalyst for this cause, we investigated the effect of water on the catalytic dehydrogenation process of alcohols. Using 1 mol% of the catalyst we report up to high yields. Moreover, we isolated ke...
Efficient and selective N-alkylation of amines with alcohols catalysed by manganese pincer complexes
Borrowing hydrogen (or hydrogen autotransfer) reactions represent straightforward and sustainable C-N bond-forming processes. In general, precious metal-based catalysts are employed for this effective transformation. In recent years, the use of earth abundant and cheap non-noble metal catalysts for this process attracted considerable attention in the scientific community. Here we show that the ...
The synthetic protocol for the reduction of alcohols to hydrocarbons by using hydriodic acid, first described by Kiliani more than 140 years ago, was improved to be more applicable to organic synthesis. Instead of a strongly acidic, aqueous solution, a biphasic toluene-water reaction medium was used, which allowed the conversion of primary, secondary and tertiary benzylic alcohols, in good yiel...
Treatment of 5-(tert-butyldimethylsilyl)-2,3-O-isopropylidene-D-ribose with lithium acetylides gave mixtures of syn- and anti-alkynols 2a-2c which were separated following protection as methoxymethyl ethers. These were converted to the corresponding iodides which underwent 6-exo-dig radical cyclisation to afford chiral cyclohexanes and carbasugars. Oxidation of the primary alcohols 6a-b gave th...
two subumits with molecular weights of 64,500 and 62,500. As its prosthetic group, non-covalelltly bound PQQ was foHnd. The dye-linked spectrophotemetric enzyme assay showed that the optimum enzyme activity occurred in the pH range about 7.0-9.0, and the ellzyme activity was inhibited by EDTA er EGTA. The enzyme showed extremely broEd substrate specificity for primary and secondary alcohols, al...
A versatile method for the synthesis of chiral 1,4-disubstituted-1,2,3-triazole derivatives starting from easily accessible naturally occurring D-or L-amino acids as chiral synthons is described. The amino acids were converted into azido alcohols, followed by copper catalyzed [3+2] cycloaddition reactions between the azido alcohols and methyl propiolate and subsequent ester aminolysis with prim...
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