2,3,5,6-四氨基吡嗪的合成

Synthesis of 2,3,5,6-Tetraaminopyrazine

以亚氨基二乙腈为起始原料,经亚硝化、环合、硝化、还原4步反应得到2,3,5,6-四氨基吡嗪（TAPA）,其结构经NMR、IR、ESI-MS确证,总产率达到26.8%。探讨了环合反应温度对中间产物2,6-二氨基吡嗪-1-氧化物（Ⅲ）和2,6-二氨基-3,5-二硝基吡嗪-1-氧化物（Ⅳ）收率的影响,及不同的硝化体系对产物Ⅳ收率的影响,并讨论了加氢还原反应的影响因素,得出最佳工艺条件为：环合反应温度25℃;硝化反应中,选择硝酸钾和发烟硫酸作为硝化体系;还原反应中,m（Pd/C）∶m（Ⅳ）=1∶15,V（CH3OH）∶V（H2O）=1∶1,反应温度为55℃,氢气压力为0.8-1.2 MPa。该合成路线的优点在于起始原料亚氨基二乙腈廉价易得,中间体易于保存,因而大幅度降低了生产成本。

2,3,5,6-Tetraaminopyrazine（TAPA） with an overall yield of 26.8% was synthesized from iminodiacetonitrile through nitrosation,cyclization,nitration and reduction reactions. All compounds were confirmed by NMR,IR,ESI-MS. The effect of cyclization reaction temperature on the yields of intermediates Ⅲ and Ⅳ,and the effect of different nitration systems on the yield of compound Ⅳ were investigated. In addition,the influence factors affecting the hydrogenation reduction reaction were discussed. The results showed that the temperature of cyclization reaction was 25 ℃,and potassium nitrate and fuming sulphuric acid was the best nitration system. The optimal conditions for the hydrogenation reduction reaction were obtained as follows： the mass ratio of Pd/C to 2,6-diamino-3,5-dinitropyrazine-1-oxide was 1∶15,the volume ratio of methanol to water was 1∶1,the reaction temperature was 55 ℃,and the hydrogen pressure was in the range of 0.8 to 1.2 MPa. The synthetic route has the advantages of commercially available starting material and good stability intermediates,which can greatly reduce the production cost.