The use of 4-hydroxymethyl-1-phenyl-2-pyrazolin-5-one ln the synthesis of new heterocycles of pharmaceutical interest

Condensation of the title compound 1 with malononitrile, ethyl cyanoacetate , cyanoacetophenone, acetophenone, 1,3-diphenylacetone, ethyl acetoacetate and/or diethyl malonate resulted in the formation of derivatives 2a-c, 6a,b and 8a,b. The reaction of 2a with hydrazine hydrate gave the diaminopyrazo le 4. On the other hand condensation of 6a,b with hydrazine hydrate gave th e 1,2-diazepinones 7a,b. Reaction of 1 with o-phenylenediamine afforded the 1,5-benzodiazepine 11. Treatment of 1 with POCl3 afforded the 4-chlorometh yl derivative 12 which underwent condensation with o-phenylenediamine to gi ve 11. Reaction of 12 with aromatic amines and hydrazines gave derivatives 13a,b and 15a,b. The structures of the unknown ring systems have ben confir med by analytical and spectral methods.