نتایج جستجو برای: nitrile oxides
تعداد نتایج: 23315 فیلتر نتایج به سال:
A convenient and efficient [3 + 2] cycloaddition reaction of alkenes alkynes with the in situ generated nitrile oxides from aldoximes presence NaCl, Oxone Na2CO3 has been developed to afford a series isoxazoles isoxazolines at room temperature yields up 85% 86%, respectively. The current methodology exhibits wide substrate scope, (hetero)aromatic aliphatic aldoximes, including acrylate esters, ...
A series of per-O-benzoylated 5-beta-D-glucopyranosyl-2-substituted-1,3,4-oxadiazoles was prepared by acylation of the corresponding 5-(beta-D-glucopyranosyl)tetrazole. As an alternative, oxidation of 2,6-anhydro-aldose benzoylhydrazones by iodobenzene I,I-diacetate afforded the same oxadiazoles. 1,3-Dipolar cycloaddition of nitrile oxides to per-O-benzoylated beta-D-glucopyranosyl cyanide gave...
Introduction The 1,3-dipolar cycloaddition reactions of nitrile oxides formed in situ (in the presence of NCS and Et3N) from the oximes of (purin-9-yl)acetaldehyde or (coumarinyloxy)acetaldehyde with allyloxycoumarins or 9-allylpurines, respectively resulted in 3,5-disubstituted isoxazolines. The similar reactions of propargyloxycoumarins or 9-propargylpurines led to 3,5-disubstituted isoxazole...
Site selectivity, regioselectivity and stereoselectivity of [2 + 3] cycloaddition of 4-trifluoromethylbenzonitrile oxide to polyunsaturated medium size rings including 1,5,9-cyclododecatriene, 11-membered sesquiterpenes, 1,3-cyclooctadiene and 5-vinyl-2norbornene were examined. Site selectivity was correlated with electron charges of alkenyl carbon atoms. Structure of the products has been esta...
BACKGROUND Nitrile hydratases are enzymes involved in the conversion of nitrile-containing compounds into ammonia and organic acids. Although they are widespread in prokaryotes, nitrile hydratases have only been reported in two eukaryotes: the choanoflagellate Monosiga brevicollis and the stramenopile Aureococcus anophagefferens. The nitrile hydratase gene in M. brevicollis was believed to have...
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