Pyrazolo[1,5-a]pyrido[3,4-e]pyrimidin-6-ones. I. Synthesis and in vitro antimicrobial evaluation.

A series of pyrazolo[1,5-a]pyrido[3,4-e]pyrimidin-6-ones (9-36) was prepared by a simple synthetic procedure based on the reaction of ethyl 7-dimethylaminovinyl pyrazolo[1,5-a]pyrimidin-6-carboxylates (1-8) and reagents (a-n) containing a primary amino group. When this set of compounds was subjected to "in vitro" antimicrobial screening, it showed no significant activity.

New 2,3-substituted 4,7-dihydro-6-(1'H-pyrazol-3'-yl)pyrazolo[1,5-a] pyrimidin-7-ones and related compounds: synthesis and benzodiazepine receptor binding study.

The reaction between two series of 7-dimethylaminovinyl pyrazolo[1,5-a]pyrimidines 4(a-r) 7a, 7d, 7f, 7(h-j) and hydrazine in acetic acid is investigated. The structure of 4,7-dihydro-6-(1'H-pyrazol-3'-yl)pyrazolo[1,5-a]pyrimidin-7- ones 5(a-r) and 7-methyl-6-(1'H-pyrazol-3'-yl)pyrazolo[1,5-a]pyrimidines 8a, 8d, 8f, 8(h-j) are attributed to the isolated products and the pathway of this reaction is suggested. The in vitro benzodiazepine receptor (BzR) affinity of the title compounds are determined by testing their ability to displace 3H-flunitrazepam from its specific binding in bovine brain membranes.