Kinetic study on the anelation of heterocycles.<b>2.</b>pyrido[2,3-<i>b</i>]pyrazine and pyrido[3,4-<i>b</i>]pyrazine derivatives synthesized by the hinsberg reaction
作者:María Inés Abasolo、Daniel Bianchi、Fabián Atlasovich、Carlos Gaozza、Beatriz M. Fernández
DOI:10.1002/jhet.5570270208
日期:1990.2
reactions to give 2-methylpyrido[2,3-b]pyrazin-3(4H)-one (3a) and 3-methylpyrido[2,3-b]pyrazin-2(1H)-one (4a) respectively. On the other hand, when the same procedure was applied to 3,4-diaminopyridine results were not so encouraging for the formation of 2-methylpyrido[3,4-b]pyrazin-3(4H)-one (3b) and 3-methylpyrido[3,4-b]-pyrazin-2(1H)one (4b). Kinetic studies were performed in aqueous buffers (pH -0.89 to
据报道,通过Hinsberg反应的吡咯并[2,3- b ]-和[3,4- b ]吡嗪衍生物II的区域选择性合成从2,3和3,4-二氨基吡啶开始,过量的丙酮酸或丙酮酸乙酯为反应物。在室温下使用无水甲醇和氯仿作为溶剂,可促进吡咯并[2,3- b ]吡嗪衍生物的良好收率(高于90%),从而促进区域选择性反应,从而生成2-甲基吡啶并[2,3 - b ]吡嗪-3 (4 H)-one(3a)和3-甲基吡啶并[2,3- b ]吡嗪-2(1 H)-one(4a) 分别。另一方面,当将相同的方法应用于3,4-二氨基吡啶时,生成2-甲基吡啶并[3,4- b ]吡嗪-3(4 H)-one(3b)和3的结果并不那么令人鼓舞。-甲基吡啶并[3,4- b ]-吡嗪-2(1 H)一(4b)。动力学研究是在水性缓冲液中进行的(pH -0.89至11.5)和不同的有机溶剂,试图提高收率并实现区域选择性。紫外分光光度法跟踪反