Cyclohepta[<i>b</i>][1,4]benzothiazines and Their Diazine Analogues. 1. Formation and Reactions of Cyclohepta[<i>b</i>][1,4]benzothiazines
作者:Kimio Shindo、Sumio Ishikawa、Tetsuo Nozoe
DOI:10.1246/bcsj.58.165
日期:1985.1
title benzothiazine (9). Although 9 was stable under basic conditions, its N-methyl cation reversibly afforded the ring-opened 2-[o-(methylamino)phenylthio]tropone in alkali. Oxidation of 9 with hydrogen peroxide in methanol underwent a rearrangement reaction to afford (exclusively) phenothiazine and its 1-formyl derivative. A similar H2O2 oxidation of 10-methoxycyclohepta[b][1,4]benzothiazine gave
2-Chlorotropone 与邻氨基苯硫醇反应得到 2-(o-氨基苯硫基)tropone,它很容易在稀甲醇 HCl 中环化得到标题苯并噻嗪 (9)。虽然 9 在碱性条件下是稳定的,但它的 N-甲基阳离子在碱中可逆地提供开环的 2-[o-(甲氨基)苯硫基]tropone。在甲醇中用过氧化氢氧化 9 进行重排反应以提供(仅)吩噻嗪及其 1-甲酰基衍生物。10-甲氧基环庚烷[b][1,4]苯并噻嗪的类似H2O2氧化主要产生甲基吩噻嗪-1-羧酸酯和3-甲酰基-1-甲氧基吩噻嗪。用过氧化氢进一步氧化这些产物,产生它们的 S-氧化物和 S,S-二氧化物。这些环庚苯并噻嗪的反应性将与 O- 和 N- 类似物的反应性联系起来讨论。