M. H. Elnagdi, M. Sallam, M. Ilias
Nov 5, 1975
Citations
0
Influential Citations
21
Citations
Journal
Helvetica Chimica Acta
Abstract
3,5-Diamino-4-phenylazo-pyrazoles (1a–1c) react with acetylacetone and with ethyl acetoacetate to yield the corresponding pyrazolo[1,5-a]pyrimidine derivatives 2a–2c and 3a–3c, respectively. Whereas 1a–1c add readily to methyl acrylate yielding the 4,5,6,7-tetrahydropyrazolo[1,5-a]-pyrimidine derivatives 5a–5c, 1a–1c add to methylacrylonitrile or methyl methacrylate only under drastic conditions to yield 5d–5f. The pyrimido[1,2:2′,3′]pyrazolo[1,5-a]pyrimidine derivatives 10a–10c are prepared by the action of acrylonitrile on 2a–2c. Compounds 10a–10c are readily converted into the corresponding oxo derivatives 12a–12c on treatment with acetic acid-hydrochloric acid mixture.