Condensation of 3-methylbenzoxazolinone with α,β-unsaturated acids |
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Authors: | B. Merdji D. Lesieur C. Lespagnol D. Barbry D. Couturier |
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Abstract: | The reaction between 3-methylbenzoxazolinone and some unsaturated acids in PPA leads to mixtures of compounds, depending on the acid: 6-crotonyl- (or cinnamoyl)-3-methylbenzoxazolinones, 2,3-dihydro-2,5-(or 2,7)dioxo-3-methylcyclopenta[f]benzoxazoles and 6-(3-oxo-indanyl)-3-methylbenzoxazolinones. The structure of the products was established by 13C and 1H nmr spectroscopy and (or) by independent synthesis. Possible mechanisms of the reaction are discussed; when competition is possible as in the last step of the cyclization, the benzene ring shows a higher reactivity than the aromatic nucleus of the benzoxazolinone; the contrary is observed when the benzene ring is p-chloro-substituted. |
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