The Stobbe condensation of methyl 4-oxo-1, 2, 3, 4-tetrahydro-2-naphthoate (III) with2, 4-dimethoxybenzaldehyde gave the chalconecarboxylic acid (IV), which was derived to 3-(5-bromo-2, 4-dimethoxybenzyl)-4-methoxy-2-naphthoic acid (XIV) by 6 steps. The compound (XIV) was also prepared from 1-methoxy-2, 3-naphthalenedicarboxylic anhydride (XV) by 4 steps. Cyclizatian reactian of (XIV) emplaying stannic chlaride as a candensing agent resulted in a replacement of bromine atom substituted in the nucleus with hydrogen to form 1, 3, 11-trimethoxy-5(12H)-naphthacenone (I). The whole reaction schema was illustrated in Chart 1.
斯托贝缩合反应中,甲基4-氧-1, 2, 3, 4-四氢-2-
萘酸酯(III)与2, 4-二
甲氧基苯甲醛反应生成了
香豆酸(IV),该化合物经过6个步骤转化为3-(5-
溴-2, 4-二
甲氧基苯基)-4-甲氧基-2-
萘酸(XIV)。化合物(XIV)也可以通过4个步骤从1-甲氧基-2, 3-
萘二酸酐(XV)合成而得。使用
氯化锡作为缩合试剂的环化反应导致核中的
溴原子被氢原子取代,形成1, 3, 11-
三甲氧基-5(12H)-
萘烯酮(I)。整个反应机制如图1所示。