نتایج جستجو برای: carbamates
تعداد نتایج: 2117 فیلتر نتایج به سال:
A direct transformation of N-aryl formamides to the corresponding carbamates via the formation of isocyanate intermediates is achieved in good yields using hypervalent iodine as an oxidant.
We report herein a straightforward general method for the synthesis of cyclic carbamates from amino alcohols and carbon dioxide in the presence of an external base and a hydroxyl group activating reagent. Utilizing p-toluenesulfonyl chloride (TsCl), the reaction proceeds under mild conditions, and the approach is fully applicable to the preparation of various high value-added 5- and 6-membered ...
Lithium cation solvation structures [Li(S)(n=1-4)](+) with ligands of cyclic or noncyclic carbamate-modified disiloxanes are optimized at B3LYP level of theory and compared to their corresponding simplified carbamates and to the organic carbonates ethylene carbonate (EC) and dimethyl carbonate (DMC). The electrostatic potentials (ESP) of these investigated carbonyl-containing solvents are mappe...
Novel Cholinesterase Inhibitors Based on O-Aromatic N,N-Disubstituted Carbamates and Thiocarbamates.
Based on the presence of carbamoyl moiety, twenty salicylanilide N,N-disubstituted (thio)carbamates were investigated using Ellman's method for their ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). O-Aromatic (thio)carbamates exhibited weak to moderate inhibition of both cholinesterases with IC50 values within the range of 1.60 to 311.0 µM. IC50 values for BChE ...
The reactions of Hoppe's lithiated carbamates with vinylboranes and boronic esters give allylic boranes/boronic esters, and subsequent addition of aldehydes provides a new route to enantioenriched homoallylic alcohols with high enantiomeric ratios and diastereomeric ratios. Specifically, reactions of sparteine-complexed lithiated carbamates with trans-alkenyl-9-BBN derivatives followed by addit...
The inhibition of hexokinase (Meyerhof and Wilson, 1948), choline oxidase (Goldfinger et al., 1947), and other enzyme systems by urethan and related carbamates has been studied extensively. Yet precisely how these compounds exert their physiological effects is unknown. Warburg (1921) considered urethan to be an "indifferent" narcotic, blocking dehydrogenases by nonspecific absorption on cellula...
Tertiary allyl- or crotylsilanes have been prepared in high er and dr via the lithiation-borylation reaction of alkyl carbamates with silaboronates. Using a related strategy, quaternary allylsilanes could be accessed in similarly high er.
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