REACTIVITY OF 7-(2-DIMETHYLAMINOVINYL)PYRAZOLO[1,5-A]PYRIMIDINES - SYNTHESIS OF PYRAZOLO[1,5-A]PYRIDO[3,4-E]PYRIMIDINE DERIVATIVES AS POTENTIAL BENZODIAZEPINE RECEPTOR LIGANDS .1.

A series of 7-methylpyrazolo[1,5-a]pyrimidines were reacted with dimet hylformamide dimethylacetal to give the corresponding dimethylaminovin yl derivatives. These were reacted with ammonium acetate affording, th rough a ring closure, a number of 6-methylpyrazolo[1,5-a]pyrido[3,4-e] pyrimidines bearing various substituents on the pyrazole ring. The ace tyl-2-hydroxy-7-methylpyrazolo[1,5-a]pyrimidine was used as starting m aterial for obtaining some O-alkyl derivatives. Catalytic transfer hyd rogenation of oxy-6-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine led t o the 2-hydroxy derivative.