Synthesis of some novel pyrazolo[3,4-d]pyrimidine derivatives

• Author(s): Campos, Ana M. F. Oliveira ; Salaheldin, Abdellatif M. ; Rodrigues, Lígia M.
• Date: 2007
• Persistent ID: http://hdl.handle.net/1822/8647
• Origin: RepositóriUM - Universidade do Minho
• Subject(s): Cyanopyrazoles; Pyrazolo[3,4-d]pyrimidines; Dimroth rearrangement
• Document Type: Article
• Language: English

Description

Reaction of ethyl imidates derived from N-aryl-5-amino-4-cyanopyrazoles with amines or arylhydrazines gave only 4-substituted pyrazolo[3,4-d]pyrimidines, resulting from cyclization followed by Dimroth rearrangement. From the reaction with arylhydrazines, a mixture of the hydrazines and their oxidized forms, the azo products, was obtained. This was proven by an independent synthesis starting from the corresponding 4-chloropyrazolo[3,4-d]pyrimidines as starting material. The structures of the compounds obtained were confirmed by mass spectrometry, 1H and 13C NMR.