[3+3] CYCLOCONDENSATION OF β-CARBONYL-SUBSTITUTED 1H-BENZO[f]CHROMENES WITH 3-AMINO-1,2,4-TRIAZOLES: SYNTHESIS OF [1,2,4]TRIAZOLO[1,5-a]PYRIMIDINES

Abstract

The reaction of β-carbonyl-substituted 1H-benzo[f]chromenes with 3-amino-1,2,4-triazoles provides a new avenue for the preparation of [1,2,4]triazolo[1,5-a]pyrimidines containing a (2-hydroxynaphthalen-1-yl)methyl group at position 6. The reaction of 2-trifluoroacetyl-1Н-benzo[f]chromene with 3-amino-5-(methylsulfanyl)-1H-1,2,4-triazole yielded a derivative of a new 4,5,5a,13a-tetrahydro-6H-benzo[5,6]chromeno[3,2-e][1,2,4]triazolo[1,5-a]pyrimidine heterocyclic system. The proposed cascade reaction mechanism includes an aza-Michael reaction, cyclodehydration, and a retro-oxa-Michael reaction.

Authors: Dmitry V. Osipov, Kirill S. Korzhenko1, Vitaly A. Osyanin*, Pavel E. Krasnikov, Yuri N. Klimochkin