Synthesis of 2-substituted 2,6-dihydro-3-hydroxy-7H-pyrazolo(4,3-d)pyrimidin-7-ones.
作者:HISAO OCHI、TADASHI MIYASAKA
DOI:10.1248/cpb.31.1228
日期:——
2-Substituted 2, 6-dihydro-3-hydroxy-7H-pyrazolo [4, 3-d] pyrimidin-7-ones bearing a methyl, phenyl, p-tolyl, m-tolyl or p-chlorophenyl group at the 2-position were synthesized by the reduction of ethyl 4-nitroso-5-hydroxy-1H-pyrazole-3-carboxylates and subsequent condensation of the resulting ethyl 4-amino-5-hydroxy-1H-pyrazole-3-carboxylates with formamide. Ethyl 4-nitroso-5-hydroxy-1H-pyrazole-3-carboxylates were prepared by nitrosation of ethyl 5-hydroxy-1H-pyrazole-3-carboxylates, which were derived from diethyl oxalacetate and monosubstituted hydrazines such as methyl-, phenyl-, p-tolyl-, m-tolyl-, and p-chlorophenylhydrazines.
2-取代的 2,6-二氢-3-羟基-7H-
吡唑并[4,3-d]
嘧啶-7-酮在 2-位上带有甲基、苯基、
对甲苯基、间
甲苯基或对
氯苯基、通过还原 4-亚硝基-5-羟基-1H-
吡唑-3-甲酸乙酯,然后用甲酰胺缩合生成的 4-
氨基-5-羟基-1H-
吡唑-3-甲酸乙酯,合成了 2-位上带有甲基、苯基、
对甲苯基、间
甲苯基或对
氯苯基的 4-亚硝基-5-羟基-1H-
吡唑-3-甲酸乙酯。4-亚硝基-5-羟基-
1H-吡唑-3-羧酸乙酯是通过 5-羟基-
1H-吡唑-3-羧酸乙酯的亚硝基化反应制备的,而 5-羟基-
1H-吡唑-3-羧酸乙酯来自
草酰乙酸二乙酯和单取代
肼,如甲基
肼、苯基
肼、对
甲苯肼、间
甲苯肼和对
氯苯肼。