ELECTROPHILIC SUBSTITUTION AT AZOMETHINE CARBON-ATOMS - REACTION OF AROMATIC ALDEHYDE HYDRAZONES WITH TRIFLUOROACETIC-ANHYDRIDE
ELECTROPHILIC SUBSTITUTION AT AZOMETHINE CARBON-ATOMS - REACTION OF AROMATIC ALDEHYDE HYDRAZONES WITH TRIFLUOROACETIC-ANHYDRIDE
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DOI：
10.1021/jo00236a026
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发表时间：
1988-01-08
影响因子：
3.6
通讯作者：
YOKOYAMA, T
中科院分区：
文献类型：
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作者：
KAMITORI, Y;HOJO, M;YOKOYAMA, T
芳香醛的二甲腙与三氟乙酸酐在室温下反应，得到高产率的带有三氟乙酰基的产物。这些亲电取代反应通常发生在甲亚胺碳上，尽管在高度富电子的系统中观察到竞争性N-酰化。使用二异丙基腙抑制这种N-酰化完全，导致高产率的C-酰化产物。三氟乙酰腙可以热环化为咪唑和恶二嗪衍生物，并且可以通过酸水解转化为1-三氟甲基1，2-二酮。
Reaction of dimethylhydrazones of aromaticaldehydes with trifluoroacetic anhydride at room temperature affords high yields of products bearing trifluoroacetyl groups. These electrophilic substitution reactions generally occur on the azomethine carbon, although competitive N-acylation is observed in highly electron-rich systems. Use of diisopropylhydrazones suppressed this N-acylation completely, leading to high yields of C-acylated products. The trifluoroacetyl hydrazones can be cyclized thermally to imidazole and oxadiazine derivatives and can be converted into 1-trifluoromethyl 1, 2-diketones by acid hydrolysis.