Pyrimidine Derivatives and Related Compounds, IX / Preparation of 5-Aminopyrazolo[1,5-a]pyrimidines and of Oxazino[4,5 : 5,6]pyrazolo[1,5-a]pyrimidines, a New Ring System
Open Access
- 1 December 1977
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung B
- Vol. 32 (12) , 1478-1481
- https://doi.org/10.1515/znb-1977-1222
Abstract
Whereas the 5-aminopyrazole derivatives (1 a, b) react with ethyl β-amino-β-trichloro-methylmethylenecyanoacetate (2) in basic media to yield the corresponding 5-aminopyrazolo[1,5-a]pyrimidine derivatives (3a, b), the reaction of la, b with 2 in refluxing acetic acid has afforded oxazino[4,5:5,6]pyrazolo[1,5-a]pyrimidine derivatives. 5-Amino-3-phenyl-4-phenylazopyrazole (12) reacted with 2 in refluxing pyridine to yield the 5-amino-2-phenyl-3-phenylazopyrazolo[1,5-a]pyrimidine derivative (18). On the other hand, the reaction of 12 and 2 in refluxing acetic acid has afforded a mixture of the oxazino[4,5:5′,6′]pyrazolo[1,5-a]pyrimidine derivatives (14) and the pyrazolo[3,4-d]-astriazine derivatives (15). The mechanism of the formation of reaction products is discussed.Keywords
This publication has 0 references indexed in Scilit: