Meisenheimer Rearrangement of Azetopyridoindoles. VII. Ring Expansion of 2-Phenylhexahydroazeto(1',2':1,2)pyrido(3,4-b)indoles by Oxidation with m-Chloroperbenzoic Acid.
作者:Takushi KURIHARA、Yasuhiko SAKAMOTO、Masato TAKAI、Hirofumi OHISHI、Shinya HARUSAWA、Ryuji YONEDA
DOI:10.1248/cpb.43.1089
日期:——
Oxidation of methyl (1, 2-cis)-2-phenyl-1, 2, 4, 5, 10, 10b-hexahydroazeto[1', 2' : 1, 2]pyrido[3, 4-b]indole-1-carboxylate (8a) with m-chloroperbenzoic acid (MCPBA) (3 eq) in methylene dichloride at room temperature unexpectedly gave 4, 10-dioxooctahydroisoxazolo[3, 2-c][1, 4]benzdiazonine (10) (44%), together with the two [1, 2]-Meisenheimer rearrangement products [11 (5%) and 12 (14%)]. The structure of 10 was unambiguously established by an X-ray analysis. On the other hand, the peracid oxidation of the corresponding 1, 2-trans isomer (17) gave hexahydroisoxazolo[2', 3' : 1, 2]pyrido[3, 4-b]indole (18) (37%) via the [1, 2]-Meisenheimer rearrangement of the N-oxide as well as dihydro-β-carboline N-oxide (19) (60%) and methyl cinnamate (20) (61%). The remarkable difference in the results of peracid oxidation between the two isomers (8a and 17) was rationalized on the basis of the molecular energy calculations using a combination of molecular mechanics (MM) and molecular orbitals (MO) methods.
使用二氯甲烷在室温下,将甲基(1, 2-cis)-2-苯基-1, 2, 4, 5, 10, 10b-六氢氮杂吖啶[1', 2' : 1, 2]吡啶[3, 4-b]吲哚-1-羧酸酯(8a)与m-氯过苯甲酸(MCPBA)(3当量)氧化,意外地得到4, 10-二氧代八氢异噁唑[3, 2-c][1, 4]苯二氮烯(10)(44%),同时还生成了两个[1, 2]-梅森海默重排产物[11(5%)和12(14%)]. 通过X射线分析明确确定了10的结构。另一方面,相应的1, 2-反式异构体(17)的过酸氧化通过N-氧化物的[1, 2]-梅森海默重排生成了六氢异噁唑[2', 3' : 1, 2]吡啶[3, 4-b]吲哚(18)(37%),以及二氢-β-卡宾N-氧化物(19)(60%)和肉桂酸甲酯(20)(61%)。基于分子力学(MM)和分子轨道(MO)方法结合的分子能量计算,合理化了两种异构体(8a和17)之间过酸氧化结果的显著差异。