High chemoselectivity of CS dipolarophile in 1,3-dipolar cycloaddition of nitrilimines and 1,2,4-triazepin-5-one derivatives: experimental, theoretical and X-ray study
作者:Saida Azzouzi、Malika El Messaoudi、M'hamed Esseffar、Rachid Jalal、Félix H. Cano、María del Carmen Apreda-Rojas、Luis R. Domingo
DOI:10.1002/poc.892
日期:2005.6
Substituted 2,7-dimethyl-3-thioxo-3,4,5,6-tetrahydro-2H-[1,2,4]triazepin-5-one reacts as a dipolarophile with several N-aryl-C-ethoxycarbonylnitrilimines, in equimolar quantities, to give, in all cases, two types of products: diethyl 3-(p-aryl)-2-[N′-(p-aryl)-N′-(2′,7′-dimethyl-5′-oxo-5′,6′-dihydro-2H-[1,2,4]triazepin-3′-yl)-hydrazino]-2,3-dihydro[1,3,4]thiadiazole-2,5-dicarboxylate (3a–3c in 20–25%
取代的2,7-二甲基-3-硫代-3,4,5,6-四氢-2 ħ - [1,2,4]三氮杂-5-酮发生反应作为亲偶极与几个ñ -芳基- Ç -ethoxycarbonylnitrilimines,以等摩尔量计,在所有情况下均提供两种类型的产物:3-乙基(对-芳基)-2- [ N '-(对-芳基)-N '-(2',7'-二甲基-5) '-oxo-5',6'-dihydro-2 H- [1,2,4] triazepin-3'-yl)-hydrazino] -2,3-dihydro [1,3,4] thiadiazole-2,5 -二羧酸酯(3a - 3c,产率为20-25%)和4-(对-芳基)-5-亚氨基-1,4-二氢[1,3,4]噻二唑羧酸乙酯(4a - 4c产率为45-50%)。当使用1:2化学计量比时,有利于产物3(50%)的形成。该反应完全是化学和区域选择性的。通过X射线晶体学测定得到的