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

• Main Author: Campos, Ana M. F. Oliveira
• Publication Date: 2007
• Other Authors: Salaheldin, Abdellatif M., Rodrigues, Lígia M.
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/1822/8647
• topic: Cyanopyrazoles; Pyrazolo[3,4-d]pyrimidines; Dimroth rearrangement; Science & Technology

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.