Reactions of 7-substituted 1, 3, 9-trimethyl-8, 9-dihydroxanthines (3) with dimethyl acetylenedicarboxylate afforded heteropropellanes (5) in good yields. The reactions with methyl propiolate afforded pyrimidodiazepines (7) as well as propellanes (6) when the xanthines have small substituents at the 7 position. The mechanisms of formation of the products are also discussed.
7-取代的1,3,9-三甲基-8,9-二氢
黄嘌呤(3)与二甲基
乙炔二
羧酸酯反应,以良好的产率得到了杂螺环烷(5)。这些反应中使用
丙炔酸甲酯时,当
黄嘌呤在7位上有较小取代基时,既得到了
嘧啶二氮杂
萘(7),也生成了螺环烷(6)。同时,对产物形成的机理也进行了讨论。