نتایج جستجو برای: Sodium cyanoborohydride
تعداد نتایج: 187583 فیلتر نتایج به سال:
Protein modification (sometimes known as crosslinking) often requires two or more steps to affix a small molecule irreversibly. Two-step reductive alkylation of the enzyme rabbit muscle aldolase with ethyl 3-C-acetoacetate and sodium cyanoborohydride attaches less radioactivity than with cyanoborohydride omitted. The C level incorporated into aldolase corresponds to only about 15–30 modified pr...
Reduction of virginiamycin S with sodium borohydride produces allo- and normal-dihydro-virginiamycin S. Reduction of the tosylhydrazone of virginiamycin S with sodium cyanoborohydride affords deoxyvirginiamycin S. These compounds are less active than virginiamycin S. Like virginiamycin S they enhance the activity of virginiamycin M1.
Reductive methylation of protein amino groups with formaldehyde and sodium cyanoborohydride is shown to give up to 25% yield of N-cyanomethyl (-CH2CN) product; on work up of the reaction this is hydrolysed back to starting amine, lowering the methylation yield. Addition of metal ions such as Ni2+, which complex with free cyanide ion, improve reductive methylation yields by suppressing by-produc...
Reduction of tissues with sodium cyanoborohydride at pH7.4 gave results identical with those obtained by KBH4 treatment. On reduction with sodium cyanoborohydride at pH 4.4, however, a previously undetected basic compound was formed and was identified by mass spectrometry and chemical degradation techniques as dihydrohydroxymerodesmosine. Histidino-hydroxymerodesmosine was not present, and furt...
A simple and efficient protocol for the construction of substituted piperazines, piperidines, thiomorpholines, decahydroquinolines, perhydrocyclopenta[b]pyridine, and pyrrolidines bearing N-hydroxy substituents through intramolecular reductive cyclization of diketoximes using sodium cyanoborohydride is described.
The first stereoselective synthesis of 2,6-trans-6-substituted-4-oxo-L-pipecolic acids using a tandem reductive amination/6-endo-trig cyclisation process is described. The sequential reduction and cyclisation mediated by sodium cyanoborohydride allowed the preparation of a series of highly functionalised 6-alkyl and 6-aryl analogues.
N-Hydroxy-desferrioxamine B (5), a postulated metabolite of the microbial product desferrioxamine B (1), has been prepared by reduction of the intermediate oxime 6 with sodium cyanoborohydride. The oxime was obtained by selective oxidation of desferrioxamine B with hydrogen peroxide and a catalytic amount of sodium tungstate dihydrate. The iron complex derived from 5 enabled definite proof of t...
Reductive aminations of the aldehyde group at C-20 position of tylosin and demycarosyltylosin (desmycosin) were carried out using primary and secondary amines in the presence of sodium cyanoborohydride. Some of these derivatives brought about higher antimicrobial and ribosome-binding activities, and the structure-activity relationship is discussed.
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