Reductive Alkylation of Hydrazine Derivatives with α-Picoline-Borane and Its Applications to the Syntheses of Useful Compounds Related to Active Pharmaceutical Ingredients
ingredients of therapeutic drugs such as isocarboxazid. An efficient method for the direct reductive alkylation of hydrazine derivatives with α-picoline-borane has been developed to synthesize a variety of N-alkylhydrazine derivatives. This method provided N,N-dialkylhydrazine derivatives and N-monoalkylhydrazine derivatives upon fine-tuning of the substrates and the reagent equivalency in a one-pot manner
Herein, we report a diaminocyclopentadienone ruthenium tricarbonyl complex-catalyzed synthesis of mono- or dialkylated acyl hydrazide compounds using the borrowing hydrogen strategy in the presence of various substituted primary and secondary alcohols as alkylating reagents. Deuterium labeling experiments confirm that the alcohols were the hydride source in this cascade process. Density functional
Herein, direct N,N-dialkylation of acylhydrazides using alcohols is reported. This catalytic protocol provides one-pot synthesis of both symmetrical and unsymmetrical N,N-disubstituted acylhydrazides using an assortment of primary and secondary alcohols with remarkable selectivity and excellent yields. Interestingly, the use of diols resulted in intermolecular cyclization of acylhydrazides, and such
1,2-Reduction of α,β-unsaturated hydrazones using dimethylamine–borane/p-toluenesulfonic acid: an easy route to allyl hydrazines
作者:Maria E Casarini、Franco Ghelfi、Emanuela Libertini、Ugo M Pagnoni、Andrew F Parsons
DOI:10.1016/s0040-4020(02)00914-6
日期:2002.9
alpha,beta-Unsaturated hydrazones can be easily converted into N-allyl hydrazines by reaction with dimethylamine-borane/p-toluenesulfonic acid under mild reaction conditions. The reduction works well for N'-allyhydrazides but N'-allyl-N,N-dimethylhydrazines are rapidly reoxidised by air and so need to be manipulated under an inert atmosphere prior to M-acylation. Competitive conjugate reduction can also be observed and the regioselectivity of the dimethylamine-borane attack is determined by steric and/or electronic factors. The procedure is also effective for the C=N reduction of unconjugated hydrazones. (C) 2002 Elsevier Science Ltd. All rights reserved.