Intermolecular bromine transfer of 2-amino-7-bromotropone derivatives catalyzed by strong acid.
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概要
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Upon heating acetic acid containg a trace amount of coned sulfuric acid at 120 °C under nitrogen, 2-bromo-7-(2-hydroxyanilino)tropone (<B>1a</B>) gave 6-bromocyclohepta[<I>b</I>][1,4]benzoxazine (<B>2a</B>) as the main product and cyclohepta[<I>b</I>][1,4]benzoxazine, its 6,8-dibromo derivative and trace amounts of other mono-, di-, and tribromo compounds. This reaction became much more complex in the presence of oxygen. A similar bromine transfer was observed for 2-bromo-7-(dimethylamino)-, 7-(2-hydroxy-5-methylanilino)-, and 7-(2-methoxyanilino)tropone although the cite of the intermolecular bromine transfer depended upon the structures of the substrates and the reaction conditions. In contrast, <B>2a</B> and 2-amino-5-bromotropone derivatives were completely stable towards the strong acid. Possible reaction pathways for this bromine transfer reaction are discussed.
- 公益社団法人 日本化学会の論文
著者
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Wakabayashi Hidetsugu
Department Of Chemistry Graduate School Of Material Science Josai University
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Ishikawa Sumio
Departmant of Civil and Environmental Engineering, Yamanashi University
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Nozoe Tetsuo
Tokyo Reseach Laboratory of Kao Soap Co., Ltd.
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Okai Harue
Tokyo Reseach Laboratory of Kao Soap Co., Ltd.
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