Title:
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Approaches to azatropones
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Previous work towards the synthesis of azatropones has been reviewed. Various routes to benz[f]azatropones and benz[f]azatropolones have been investigated. The acyloin reaction on methyl-N-[2-methoxycarbonylethyl]-anthranilate led to a variety of products, in which the presence of the desired seven membered ring ketol could only be inferred. Claisen condensation of diethyl oxalate with ethyl-N-[o-ethoxycarbonylmethylphenyl]-N-toluene-p-sulphonylglycine led unexpectedly to a known substituted oxindole as well as to other products. The possible mechanism is discussed. Claisen condensation of diethyl malonate with methyl-N-ethoxycarbonylmethyl-N-toluene-p-sulphonyl anthranilate, uder two different sets of reaction conditions, led to two different byt related indolone derivatives of unusual structure, the evidence for which is discussed: a mechanism for their formation is proposed. Some brominated derivates of 2,3,4,5-tetraahydrobenz[f]azepin-5-one have been synthesised, together with sundry oxidation, dehydrobromination, and dehydrogenation products. An attempt to synthesise benz[f]azepin-3-one gave a known dimeric product containing the quinoline nucleus: presumably by a mechanism involving an unusual type of benzoin reaction. Attempts to prepare dibenz[b,e]azepin-4-one are described. Suggestions for further work in this field are made.
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