An easy synthesis of 5-functionally substituted ethyl 4-amino-1-aryl- pyrazolo-3-carboxylates: interesting precursors to sildenafil analogues.
3-Oxo-2-arylhydrazononitriles 1a-c react readily with chloroacetonitrile, ethyl chloroacetate, and with phenacyl chloride to give 4-aminopyrazoles 4a-e. The pyrazolo[4,3-d]pyrimidine derivatives 7 and 10 are synthesized via reaction of the aminopyrazole 4b with phenylisothiocyanate and DMFDMA/NH4OAc respectively.
Ghozlan
Said A S
SA
Department of Chemistry, Faculty of Science, Cairo University, Giza, A. R. Egypt. s_ghozlan@yahoo.com
Badahdah
Khadija O
KO
Abdelhamid
Ismail A
IA