Copper promoted desulfurization and C-N cross coupling reactions: Simple approach to the synthesis of substituted 2-aminobenzoxazoles and 2,5-disubstituted tetrazole amines

Abstract

Copper-supported novel, facile and efficient methods for the synthesis of various 2-amino-benzoxazoles and 2,5-diphenyltetrazoleamines have been demonstrated. The reaction procedures are simple, with excellent substrate tolerance in good to high yields thus paving an excellent and useful way to establish a library of potentially active drug molecules. This methodology represents the first concept of copper-catalyst promoted domino C-N cross-coupling reaction towards the construction of 2-aminobenzoxazoles. In addition, we described report for the synthesis of 2,5-diaryltetrazoleamines using copper via inter molecular C-N cross-coupling reaction with aryl iodides. The proposed reaction mechanism involves copper based desulphurization/nucleophilic substitution and subsequent C-N cross-coupling reactions. We established numerous applications of this methodology for synthesizing diverse heterocyclic derivatives i.e. both electron rich and electron deficient systems. Keywords: Desulfurization, Nucleophilic substitution, Copper catalyst, Mono/domino C-N cross-coupling reaction, Heterocyclic compounds