PYRIDAZINE DERIVATIVES AND RELATED-COMPOUNDS .5. PYRAZOLO{[}3,4-C]PYRIDAZINE - SYNTHESIS AND SOME REACTIONS

This paper describes the synthesis of three pyrimido{[}1',2':1,5]pyrazolo{[}3,4-c]pyridazines (6,7 and 9) starting from 3-amino{[}3,4-c]pyridazine (1). Pyrimido{[}5',4':5,6]pyrimido{[}1',2':1,5]pyrazolo{[}3,4-c]pyridazine derivative (8) was obtained by condensing 7a with formamide. Reactions of 1 with acetic anhydride, benzoyl chloride, phenacyl bromide and 4-chlorophenacyl bromide gave 3-substituted amino derivatives.