Reaction of benzaldehyde (1a) with methyl acetoacetate (2) in the presence of morpholine (or piperidine) and AcOH in refluxing C6H6 yielded a new condensation product, 1, 5-dimethoxycarbonyl-2-methyl-4-morpholino (or piperidino)-6-phenyl-1, 3-cyclohexadiene (3a or 10a), along with a usual product, benzylideneacetoacetate (4a). Under the conditions determined as optimum, 3a was prepared in 86% yield. However, reaction of 1a and 2 in the presence of morpholine (or piperidine) in EtOH solution yielded 4a, a poly-substituted cyclohexanone derivative (5a) and a cyclohexenone derivative (7a), while the production of 3a was not detected. Compound 3a (or 10a) was also prepared by an alternative procedure of condensation of 5a or 6a with morpholine (or piperidine) in the presence of TiCl4. Compound 6a was prepared by dehydration of 5a under acidic conditions. Acid hydrolysis of 3a afforded 6'a, which is the C-4 epimer of 6a. The configurations of 3a, 6a and 6'a were assigned on the basis of the proton nuclear magnetic resonance (1H-NMR) spectra. Mechanisms of the formation of 3a are discussed. Some of 3 and related compounds exhibited potent calcium channel-blocking activity.
苯甲醛(1a)与
乙酰乙酸甲酯(2)在
氟化
哌啶(或
哌啶)和
醋酸的存在下,在回流的苯(
C6H6)中发生反应,生成了一种新的缩合产物,即1, 5-二甲氧基羰基-2-甲基-4-
氟化
哌啶(或
哌啶)-6-苯基-1, 3-环
己二烯(3a或10a),同时还获得了常见产物
苯乙烯基
乙酰乙酸酯(4a)。在确定为最佳条件下,3a的产率为86%。然而,在
乙醇溶液中,1a与2在
氟化
哌啶(或
哌啶)存在下反应只生成了4a,一个多取代的
环己酮衍
生物(5a)和一个
环己烯酮衍
生物(7a),而未检测到3a的生成。化合物3a(或10a)也可以通过5a或6a与
氟化
哌啶(或
哌啶)的缩合反应在TiCl4存在下合成。化合物6a是通过在酸性条件下脱
水5a而获得的。3a的酸性
水解产物是6'a,后者是6a的C-4表异构体。3a、6a和6'a的构型是根据氢核磁共振(1H-NMR)谱进行分配的。讨论了3a的形成机制。部分3和相关化合物表现出了强效的
钙通道阻滞活性。