吡啶并吡嗪/咪唑杂环化合物的合成研究

以2,3-二氨基吡啶或2,3,5,6-四氨基吡啶盐酸盐等为原料合成了吡啶并吡嗪、吡啶并咪唑及吡啶并二咪唑氮杂环衍生物。探讨了反应条件对产物收率的影响,初步确定了优化反应条件。对2,3-二甲基吡啶并吡嗪及2,3-二乙基吡啶并吡嗪的合成,氯化铵-甲醇体系具有明显的催化效果。使用4,5-二羟基咪唑烷-2-酮代替乙二醛与2,3-二氨基吡啶反应,可显著提高吡啶并吡嗪的合成收率;对于吡啶并咪唑和2-甲基吡啶并咪唑的合成,以2,3-二氨基吡啶与原甲酸三乙酯或原乙酸三甲酯为原料,在磷钼酸催化下反应,收率达50%以上;对于吡啶并[2,3-b:5,6-b']二咪唑和2,6-二甲基吡啶并[2,3-b:5,6-b']二咪唑的合成,分别以2,3,5,6-四氨基吡啶盐酸盐与原甲酸三乙酯和原乙酸三甲酯为原料在磷钼酸催化下反应,收率可达68.7%和66.5%。

Study on the Synthesis of the Compounds of Pyridopyrazinedione/Imidazole

Several pyridopyrazinedione, pyridinoimidazole and pyridodiimidazole compounds were synthesized from2, 3-diaminopyridine and 2, 3, 5, 6-tetraaminopyridine hydrochloride and the reaction conditions were investigated.NH4Cl-CH3 OH system has significant catalytic effects on the synthesis of 2,3-dimethypyrido [2,3-b] pyrazine and2,3-diethypyrido [ 2,3-b] pyrazine. Replacement of glyoxal with 4,5-dihydroxy-imidazolidin-2-one increased the product yield by its reaction with 2,3-diaminopyridine. Phosphomolybdic acid was a preffered catalyst for the preparation of pyridinoimidazole and 2-methyl pyridinoimidazole. Likewise, 2,3,5,6-tetraaminopyridine hydrochloride was reacted with triethyl orthoformate and trimethyl orthoacetate under catalysis of phosphomolybdic acid gave 2,6-dihydro-pyrido [2,3-b：5,6-b′] diimidazole and 2,6-dimethy-pyrido [2, 3-b：5, 6-b′] diimidazole in yield of 68.7% and66.5%, respectively.