Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
3-Dicyanomethylene-3-phenylpropionitrile coupled with diazotized aromatic amines (Ar-NH2) to afford hydrazono derivatives. The latter (Ar = C6H5, 4-CH3C6H4, 4-CH3OC6H4, and 4-ClC6H4) were readily cyclized upon reflux in aqueous NaOH to 3(2H) pyridazinimine derivatives, which were readily transformed into their corresponding pyridazinone derivatives on reflux in ethanolic HCl. The pyridazinimines undergo reductive cleavage and recyclization via loss of ammonia to afford the corresponding N-aryl pyrroles on reflux in glacial acetic acid with Zn dust. The pyridazinone derivatives, however, undergo the same reaction but with loss of the aromatic amine moiety to afford only one pyrrolone derivative. The hydrazono derivative (Ar = 2-NCC6H4) was cyclized into pyridazino[3,2-b]quinazolin-6-imine, which is easily converted into pyridazino[3,2-b]quinazolin-6-one on reflux in ethanolic HCl. The latter compound is also obtained from the hydrazo derivatives (Ar = 2-HOOCC6H4 and 2-MeOOCC6H4) by reflux in aqueous NaOH.
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