Synthesis of 2-Aryl-2,3-dihydro-4-styrylpyrimidodiazepines in the Reaction of 4,5,6-Triaminopyrimidine and 2,4,5,6-Tetraaminopyrimidine with Diarylidenacetones

摘要

New 6-amino and 6,8-diamino-2-aryl-2,3-dihydro-4-styryl-1H-pyrimido[4,5-b][1,4]diazepines were obtained in the reaction of 2,4,5,6-tetraaminopyrimidine 1a and 4,5,6-triaminopyrimidine 1b with one equivalent of the diarylideneacetones 2 in absolute ethanol with acetic acid as the catalyst. Structure analysis of 6-amino and 6,8-diamino-2-aryl-2,3-dihydro-4-styryl-1H-pyrimido[4,5-b][1,4]diazepines 3a-i, determined by detailed nmr measurements, reveals a high regioselectivity of this reaction.