NEW HETEROCYCLIC SYNTHESES FROM HYDRAZIDOYL HALIDES - CONVENIENT SYNTHESES OF FUSED PYRIMIDINES, PYRIDAZINES, AND QUINAZOLINES

Aminocyanopyrazole derivatives and pyrazolo[2,3-a]quinazolones were obtained in good yields from hydrazidoyl halides and malononitrile. Pyrazolo[3,4-d]pyridazine and pyridazo[4'',5'':1,2]pyrazolo[1,5-a]quinazoline derivatives were synthesized in quantitative yields by reaction of hydrazine hydrate with 2 and 16, respectively. A novel ring system, a 3-substituted tetrahydro derivative of 7-oxo-6H,8H-pyridazo[3'',4'',5''-c''d]-plrazolo[3,4-d]pyrimidine was prepared by reaction of 6 with dimethyl carbonate. Pyrazolo[3,4-d]pyrimidine-4,6-dithiones were obtained in good yields by reaction of 2 with carbon disulfide. The structures of the products were assigned and confirmed on the basis of their elemental analyses, spectral data, and alternate synthesis wherever possible. The structures of the parent fused heterocyclic systems discussed in this work are summarized.