Facile synthesis of some novel pyrrole and pyridazinoquinazolone derivatives

✍ Scribed by Zaghloul E. Kandeel; Ahmad M. Farag; Fathy M. Abdelrazek

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: English
• Weight: 376 KB
• Volume: 6
• Category: Article
• ISSN: 1042-7163
• DOI: 10.1002/hc.520060314

✦ Synopsis

3-Dicyanomethylene

-3-phenylpropionitrib coupled with diazotized aromatic amines (Ar-NHJ to afford hydrazono derivatives. The latter (Ar = C a 5 , 4-C H 3 C a 4 , 4-CH@c&, and 4-C1C6H4) 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 HCI. The pyridazinimines undergo reductive cleavage and recyclization via loss o f ammonia to afford the corresponding N-aryl pyrroles on reflux in glacial acetic acid with Z n 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-6one on reflux in ethanolic HCI. The latter compound is also obtained from the hydrazo derivatives (Ar = 2-HOOCC6H4 and 2-MeOOCCa4) by refztu: in aqueous NaOH.