Cyclohepta[<i>b</i>][1,4]benzothiazines and Their Diazine Analogues. 2. Formation and Properties of Cyclohepta[<i>b</i>]quinoxalines
作者:Kimio Shindo、Sumio Ishikawa、Tetsuo Nozoe
DOI:10.1246/bcsj.62.1158
日期:1989.4.15
2-Chloro- or 2-methoxytropone reacts with o-phenylenediamine to give 2-(o-aminoanilino)tropone, which upon heating provides 6H-cyclohepta[b]quinoxaline (10a). Upon acidification, 10a reversibly gives a green cation, 9a. 10a is easily converted, especially under basic conditions, into the oxidative dimer 16a, which reproduces 9a by reduction with Zn in acetic acid. The isopropyl derivatives of these compounds are prepared by the same method from 5-isopropyl-2-methoxytropone. The 5-methyl (21a) and 5,11-dimethyl derivatives 23 are made by the reaction of 2-chloro- or 2-methoxytropone with N-methyl- and N,N′-dimethyl-o-phenylenediamines. However, the methylation of 21a with methyl fluorosulfate affords 5,11-dihydro-8,11-dimethyl-6H-cyclohepta[b]quinoxaline-5,6-sultone. H2O2 oxidation of 10a mainly gives 16a in addition to a small quantity of 6H-cyclohepta[b]quinoxalin-6-one. Compound 21a is stable under basic conditions, but 23 rearranges under alkaline conditions to give, among other unidentified products, N-methyl-N-[o-(methylamino)phenyl]benzamide and 5,10-dihydro-5,10-dimethyl-2-phenazinecarbaldehyde. Reactions of title compounds with alkali and hydrogen peroxide are compared with those of O- and S-analogues.
2-氯或2-甲氧基脱氢松香与邻苯二胺反应生成2-(邻氨基苯基氨基)脱氢松香,随着加热生成6H-环七[b]喹喏啉(10a)。在酸性环境下,10a 可逆地生成绿色阳离子9a。10a 易于转化,特别是在碱性条件下,生成氧化二聚体16a,16a通过与醋酸中的Zn还原可再生9a。这些化合物的异丙基衍生物是通过5-异丙基-2-甲氧基脱氢松香用同样的方法制备的。5-甲基(21a)和5,11-二甲基衍生物23是通过2-氯或2-甲氧基脱氢松香与N-甲基和N,N'-二甲基邻苯二胺反应制得的。然而,用氟甲基硫酸盐对21a进行甲基化反应则得到5,11-二氢-8,11-二甲基-6H-环七[b]喹喏啉-5,6-磺酸酯。10a的H2O2氧化反应主要生成16a,外加少量的6H-环七[b]喹喏啉-6-酮。化合物21a在碱性条件下稳定,但23在碱性条件下发生重排,生成包括N-Methyl-N-[o-(甲基氨基)苯基]苯胺和5,10-二氢-5,10-二甲基-2-苯嗪羧醛在内的其他未鉴定产品。标题化合物与碱和氢过氧化物的反应与O-和S-类比的反应进行比较。