Studies with heteroaromatic Aza compounds: A novel synthesis of phthalazines

✍ Scribed by Elnagdi, Mohamed Hilmy ;Ibrahim, Nadia Sobhy ;Sadek, Kamal Usef ;Mohamed, Mona Hassan

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 212 KB
• Volume: 1988
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.198819881014

✦ Synopsis

A new route for the synthesis of phthalazines 6 by reaction of benzylidcnemalononitrile (3) with 4-substituted 2,3-dihydro-5methyl-4pyridazinecarbonitriles 2 is reported.

Synthetic approaches to phthalazines utilize either reaction of ortho-substituted benzenes with hydrazines or cyclization of azinesl-'). A synthesis of phthalazines from reaction of benzene with nitrile imine has also been reported4'. None of these approaches can be utilized easily to produce polyfunctionally substituted phthalazines. For synthesis of polyfunctionally substituted azines of potential biological activity5), we here report the synthesis of several new 5-methyl-3-0~0-4-pyridazinecarbonitrils 2 and their reactions with cinnamonitriles. Thus, we found that the arylhydrazones la-c react with ethyl cyanoacetate in the presence of ammonium acetate to yield the pyridazines 2a-c. Compound 2a was previously synthesized by us') and also, in lower overall yield, by Gewald and Hain7'.

Compounds 2a, b reacted with benzylidenemalononitrile (3) to