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US 4,289,704 AGranted
Preparation of gamma-pyrones
AssigneePfizer Inc.
InventorsThomas M. Brennan, Daniel P. Brannegan, Paul D. Weeks, Donald E. Kuhla
Life of this patent
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Abstract
2-Methyl-3-hydroxy-4H-pyran-4-one is prepared by contacting 1(2-furyl)-1-ethanol in aqueous solution with two equivalents of a halogen oxidant at room temperature and then heating until the hydrolysis of the formed 4-halo-dihydropyran intermediate is substantially complete. Other valuable related gamma-pyrones are prepared in analogous manner from appropriate alcohols.
Claims2
A process for preparing a compound of the formula ##STR30## wherein R is hydrogen, alkyl of 1 to 4 carbon atoms, phenyl or benzyl;
- R' is hydrogen, alkyl of 1 to 4 carbon atoms or ##STR31## wherein R" is methyl, ethyl or phenyl;
- R"' is hydrogen or alkyl of 1 to 4 carbon atoms;
- and X is bromine, or chlorine which comprises contacting a compound of the formula ##STR32## in a reaction-inert solvent at a temperature of -50.degree. to 50.degree. C. with at least one equivalent of a halogen oxidant selected from the group consisting of chlorine, bromine, bromine chloride, hypochlorous acid, hypobromous acid or mixtures thereof until the reaction is substantially complete.
Dependencies are inferred from the claim text.