Preparation of 2-Amino-6-methyl-4-propyl-4,5dihydro[1,2,4]triazolo[1,5-a]pyrimidin-5-one

Abstract

以N-正丙基-1H-1,2,4-三唑-3,5-二胺为起始原料与苯甲醛反应合成化合物I；化合物1与3-甲氧基-2-甲基丙烯酸甲酯反应生成化合物II，化合物II脱去苯甲醛保护得到目标产物2-氨基-6-甲基-4-正丙基-1,2,4-三唑[1,5-a]并嘧啶-5-酮(化合物III)。考察催化剂、摩尔比、反应温度对反应的影响，考察苯甲醛的回收利用情况。结果表明：化合物I的最佳工艺条件为冰醋酸催化剂，回流反应，化合物II的最佳催化剂为甲醇钠，115℃反应；酸性条件下脱保护得到目标产物。在最佳工艺条件下，化合物I的收率为96%以上，化合物II的收率达到90%以上，化合物III的收率在95%以上。 Compound I was synthesized from N-propyl-1H-1,2,4-Triazole-3,5-diamine as the starting material with benzene formaldehyde; which was then reacted Methyl (E)-3-Methoxy-2-Methyl propenoate obtain compound II；finally, compound II was then deprotected to obtain target product 2-Amino-6-methyl-4-propyl-4,5-dihydro[1,2,4]triazolo[1,5-a]pyrimidin-5-one (compound III). The reaction was optimized by studying the catalyst, molar ratio, reaction temperature, and the recovery of benzaldehyde was further considered. The results showed that the best process conditions of compound I were ice acetic acid catalyst, reflux reaction, compound II’s best catalyst was sodium methanol, 115˚C reaction, and the target product was obtained under acidic conditions. Under the best process conditions, the yield of compound I is more than 96%, the yield of compound II is more than 90%, and the yield of compound III is more than 95%.