Chelate synthesis of pyrazolyl(ethoxycarbonyl)ketene aminals,the precursors of functionalized pyrazolo[1,5-c]pyrimidines

A scheme for the preparation of novel synthetic reagents. pyrazolyl(ethoxycarbonyl)ketene aminals, from acetyl(ethoxycarbonyl)ketene (N-benzoyl)aminalvia its difluoroboron chelate is suggested. The possibility of cyclization of the ketene aminals obtained into functionally substituted pyrazolo[1,5-c]pyrimidines is shown.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2211–2214, December, 1994.This work was carried out with the support of the International Science Foundation (ISF, Grant No. M5Q 000), and a part of the work was supported by the Russian Foundation for Basic Research (Project No. 94-03-08964).