S. S. Ibrahim, H. M. El-Shaaer, A. Hassan
Jan 1, 2002
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Influential Citations
13
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Journal
Phosphorus, Sulfur, and Silicon and the Related Elements
Abstract
2-Methyl-4-oxo-4 H -1-benzothiophenopyran ( 3 ) was prepared together with its thio analoge 4 . A facial conversion of 3 and some 2-methyl-4-oxo-4 H -1-benzopyrans ( 5 ) to 2-oxo-2 H -1-pyrans and 2(1 H )-pyridones was achieved under the influence of some carbon nucleophiles (NCCH 2 R). The behavior of the active methyl group of 3 or 5 toward benzaldehyde, ethyl oxalate, and phthalic anhydride was discussed, where the styryl derivatives 12 , 16 , the pyruvates 20 , 24 , and phthalide 33 were obtained, respectively. Bromination of 12 , 16 , followed by reaction with phenylenediamine and 2-aminothiophenol, led to the formation of quinoxalinyl and benzothiazinyl derivatives. Treatment of the pyruvic acids derived from 20 , 24 with phenylenediamine gave quinoxalinyl derivatives, but with benzaldehyde and aniline, atophan analogues were formed. In addition, compound 33 was isomerized to the corresponding phthalone derivative. Compound 3 was allowed to react with amines, hydrazine, hydroxylamine, thiourea, and guanidine, where opening of the pyrone ring was observed and alkylaminobutene, pyrazole, isoxazole, aminopyrimidine, thioxopyrimidine derivatives were obtained, respectively.