无外加催化剂条件下邻取代芳香醛与5, 5-二甲基-1, 3-环己二 酮的反应研究

在DMF溶剂中,不外加催化剂使邻取代芳香醛(1)与5,5-二甲基-1,3-环己二酮(2)发生缩合和加成反应生成3,3,6,6-四甲基-4a-羟基-9-芳基-1,8-二氧代-2,3,4,4a,5,6,7,8,9,9a-十氢化-1H-氧杂蒽(3a-3d)。在同样条件下,邻羟基芳香醛与5,5-二甲基-1,3-环己二酮则发生缩合、加成和脱水反应生成3,3-二甲基-9-(5,5-二甲基-3-羟基-2-环己烯-1-酮-2-基)-1-氧代-2,3,4,9-四氢化-1-氧杂蒽(4a-4b)。用单晶X-射线分析法确定了产物3a和4a的晶体结构。

Studies on the uncatalyzed reactions of o-substituted aromatic aldehydes with 5, 5-dimethyl-1, 3-cyclohexanedione

The uncatalyzed reactions of o-substituted aromatic aldehydes with 5, 5-dimethyl-1, 3-cyclohexanedione in DMF were studied. The condensation and addition reaction of o-substituted aromatic aldehydes (1) with 5, 5-dimethyl-1, 3-cyclohexanedione (2) afforded 3, 3, 6, 6-tetramethyl-4a-hydroxyl-9-aryl-1, 8-dioxo-2, 3, 4, 4a, 5, 6, 7, 8, 9, 9a-decahydro-1H-xanthene (3a-3d). However, treatment of o- hydroxyl-aromatic aldehydes with 5, 5-dimethyl-1, 3-cyclohexanedione under the same conditions afforded 3, 3-dimethyl-9-(5, 5-dimethyl-3- hydroxyl-2-cyclohexene-1-one-2-yl)-1-oxo-2, 3, 4, 9-tetrahydro-1H- xanthene (4a-4b). The crystal structures of 3a and 4a were determined by X-ray diffraction analysis.