Application of cyclic ketones in MCR: Ugi/amide coupling based synthesis of fused tetrazolo[1,5-a][1,4]benzodiazepines

Azido-Ugi reaction involving cyclic ketone, primary amine, isonitrile, and azide afforded substituted tetrazole derivatives 5. These intermediates were hydrolyzed to corresponding acid derivatives. EDAC/HOBt mediated amide bond formation of 5 gave fused tetrazolo[1,5-a][1,4]benzodiazepine 6 in high yield and good diversity. (C) 2014 Elsevier Ltd. All rights reserved.