Friedel–Crafts cyclisations. Part III. Synthesis of derivatives of 2(1H)-quinolone (carbostyril) by aluminium chloride-catalysed cycloeliminations of cinnamanilide and related compounds
Friedel–Crafts cyclisations. Part III. Synthesis of derivatives of 2(1H)-quinolone (carbostyril) by aluminium chloride-catalysed cycloeliminations of cinnamanilide and related compounds
复制标题
第三部分：通过氯化铝催化环消除肉桂苯胺和相关化合物合成 2(1H)-喹诺酮（喹诺酮）衍生物。
DOI：
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发表时间：
1972
期刊：
影响因子：
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通讯作者：
G. Williams
中科院分区：
文献类型：
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作者：
K. M. Johnston;R. Luker;G. Williams
为了将肉桂苯胺转化为 2(1H)-喹诺酮（喹诺酮），使用 3 mol。相当于优选催化剂为氯化铝；然而，从4-苯基-3.4-二氢-2(1H)-喹诺酮得到的2(1H)-喹诺酮收率低，表明肉桂苯胺中β-芳基的损失可能几乎与环化同时发生。 N-芳基核中的对硝基或对甲氧基以及肉桂酰基部分中的α-氯取代基可防止环化。然而，对氯肉桂酰苯胺环化为 4-苯基-2(1H)-喹诺酮，同时失去氯化氢。环消除的范围通过从 2',4',5'-三氯肉桂苯胺形成 5,6,8-三氯-2(1H)-喹诺酮来表明。尽管甲基的迁移不伴随邻位肉桂酰苯胺的环化，但通过将邻甲基移动至相邻的间位允许2',6'-二甲基肉桂酰苯胺环化。
For the conversion of cinnamanilide into 2(1H)-quinolone (carbostyril) the use of 3 mol. equiv. of the catalyst, aluminium chloride, is desirable; the low yield of 2(1 H)-quinolone obtained from 4-phenyl-3.4-dihydro-2(1H)-quinolone however, indicated that loss of the β-aryl group from cinnamanilide probably occurs virtually simultaneously with the cyclisation. Cyclisation was prevented by either a p-nitro- or a p-methoxy-group in the N-aryl nucleus, and also by an α-chloro-substituent in the cinnamoyl moiety. p-Chlorocinnamanilide was cyclised, however, to 4-phenyl-2(1H)-quinolone with loss of hydrogen chloride. The scope of the cycloelimination was indicated by the formation of 5,6,8-trichloro-2(1H)-quinolone from 2′,4′,5′-trichlorocinnamanilide. Although migration of a methyl group did not accompany the cyclisation of o′-methylcinnamanilide, cyclisation of 2′,6′-dimethylcin-namanilide was permitted by shift of an ortho-methyl group to the adjacent meta-position.