Solid-phase synthetic method for (±)-α-amino acids via phase-transfer catalytic alkylation
A solid supported glycineimine t-butyl ester was designed and successfully applied to the synthesis of (±)-α-amino acids. The phase-transfer catalytic alkylation, followed by acidic hydrolysis and benzoylation gave N-benzoyl-α-amino acid tert-butyl esters in high yields (up to 92%).
Regioselective hydrolysis of cocaine and a convenient acylation procedure by benzoylecgonine
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.
An oxidative transformation of N′-phenylhydrazide to t-butyl ester using a copper(II) halide-lithium t-butoxide system
Reactions of hydrazides or N1-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.