Synthesis of new 4-oxo-1,2,3,4-tetrahydropyrazolo[5,1-с][1,2,4]triazines

Abstract

Alkylation of 7-amino-3-tert-butyl-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carbonitrile led to N1-substituted derivative, which upon treatment with NaH and MeI in DMF was converted to 1-benzyl-3-tert-butyl-7-dimethylamino-4-oxo-1,4-dihydropyrazolo-[5,1-c][1,2,4]triazine-8-carbonitrile. The latter reacted with Grignard reagents to give high yields of new 3-tert-butyl-3-R-4-oxo-1,2,3,4-tetrahydropyrazolo[5,1-c][1,2,4]triazines (R = Alk, Ph). The reaction course and conditions were studied, and spectral characteristics of the products are discussed.