C–C recyclizations of some 2,7-disubstituted 6-ethoxycarbonylpyrazolo[1,5-a]pyrimidines
作者:G. G. Danagulyan、A. P. Boyakhchyan、A. G. Danagulyan、H. A. Panosyan
DOI:10.1007/s10593-011-0760-x
日期:2011.6
(including NOESY) NMR spectroscopic data there were formed, along with the cyclization products, noncyclic condensation adducts (as cyano derivatives) from ethyl ethoxymethylenecyanoacetate with 5-aminopyrazoles. In the presence of alcoholic alkaline solution these were also transformed in high yield to 6-carbamoyl-7-hydroxypyrazolopyrimidines. When refluxed for a longer time in 12% aqueous alcoholic alkaline
乙氧基亚甲基乙酰乙酸乙酯和乙氧基亚甲基氰乙酸乙酯在乙醇中与3-取代的3-氨基吡唑和5-氨基-1,2,4-三唑缩合,得到2-取代的6-乙氧基-羰基-7-甲基-和7-氨基-6-乙氧基羰基吡唑并[1,5-a]嘧啶以及7-氨基-6-乙氧基羰基-1,2,4-三唑并[1,5-a]嘧啶。在碱的存在下,它们分别重排为2-取代的6-乙酰基-7-羟基-和6-氨基甲酰基-7-羟基吡唑并[1,5-a]嘧啶,以及6-氨基甲酰基-7-羟基-1,2 ,4-三唑并[1,5-a]嘧啶。根据1形成了H(包括NOESY)NMR光谱数据,以及环化产物,是乙氧基亚甲基氰基乙酸乙酯与5-氨基吡唑的非环状缩合加合物(作为氰基衍生物)。在醇碱性溶液的存在下,它们也以高收率转化为6-氨基甲酰基-7-羟基吡唑并嘧啶。当在12%的乙醇碱性水溶液中回流更长的时间时,6-乙氧基羰基-2,7-二甲基吡唑并[1,5-a]嘧啶和6-乙酰基-7-羟基-2-甲基吡唑并[1