Regioselective Hydrolysis of Cocaine and A Convenient Acylation Procedure by Benzoylecgonine
摘要:
Regioselective hydrolysis of cocaine led, according to the reaction conditions, either to benzoylecgonine or to ecgonine methyl ester. Acylation with benzoylecgonine was readily achieved when benzotriazolyloxytrisdimethylaminophosphonium (BOP) was used as a coupling agent.
Reactions of hydrazides or N′-phenylhydrazides with a copper(II) reagent prepared from copper(II) bromide and lithium t-butoxide smoothly proceeded to give the corresponding t-butyl ester in high yield.
A solid supported glycineimine t-butyl ester was designed and successfully applied to the synthesis of (divided by)-alpha-amino acids. The phase-transfer catalytic alkylation, followed by acidic hydrolysis and benzoylation gave N-benzoyl-alpha-amino acid tert-butyl esters in high yields (up to 92%). (C) 2004 Elsevier Ltd. All rights reserved.
A Convenient Synthesis of t-Alkyl Esters of Amino Acids<sup>1a</sup>