- Reactions of p-Coumaric acid with nitrite: Product isolation and mechanism studies
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p-Coumaric acid (1) is an abundant plant phenolic acid, a dietary chemoprotectant, and an antioxidant. The chemoprotective properties of I were demonstrated in vitro by its reaction with NaNO2 in H2O over a range of pH values. The reaction pathway of I with nitrite is dependent on pH. 4-Hydroxybenzaldehyde (3, 16%), 1′,4-dihydroxybenzeneacetaldehyde oxime (5, 59%), and 4-hydroxy-1′-oxo-benzeneacetaldehyde aldoxime (7, 26%) and 7-hydroxy-1,2(4H)-benzoxazin-4-one (11, 6%) were each formed at pH 2, whereas 4-(2-oxido-1,2,5-oxadiazol-3-yl)phenol (13) was formed at pH 3 (6%) and pH 7 and 10 (both 1%). Products were isolated and characterized by NMR and MS spectral analyses. Formation of benzoxazinone (11) requires the 4-phenolic functional group and the conjugated propenoic acid side chain of p-coumaric acid. The mechanism for nitrosation at pH 2 was examined by reacting I in H218O/NaNO2.
- Torres y Torres, Janelle L.,Rosazza, John P. N.
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p. 1486 - 1492
(2007/10/03)
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- The Unambiguous Syntheses of the 2,5-Diphenyloxazole Metabolites
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The syntheses of the six possible monoxydroxy derivatives and the N-oxide of 2,5-diphenyloxazole are described.Attempts towards the synthesis of 2,5-diphenyloxazol-4(5H)-one are also reported.
- Jacobsen, Noel W.,Philippides, Athena
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p. 1335 - 1338
(2007/10/02)
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