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US 4,059,595 AGranted
Process for preparing 3-oxy-4H-pyran-4-one derivatives
AssigneeOtsuka Kagaku Yakuhin Kabushiki Kaishi
InventorsTatsuya Shono, Yoshihiro Matsumura
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Abstract
A process for preparing a 3-oxy-4H-pyran-4-one derivative which comprises the steps of: 1. epoxidizing a 3-oxo-3,6-dihydro-2H-pyran derivative with a peroxide to obtain a 4,5-epoxy-3-oxotetrahydropyran derivative, and 2. heating the 4,5-epoxy-3-oxotetrahydropyran derivative.
Claims10
A process for preparing a 3-oxy-4H-pyran-4-one derivative represented by the formula:
- ##STR5## wherein R.sub.1 is hydrogen or straight-chain or branched-chain alkyl having 1 to 10 carbon atoms which comprises the steps of:
- (1) epoxidizing a 3-oxo-3,6-dihydro-2H-pyran derivative represented by the formula:
- ##STR6## wherein R.sub.1 is as defined above and R.sub.2 is hydrogen, straight-chain or branched-chain alkyl having 1 to 6 carbon atoms or straight-chain or branched-chain acyl having 1 to 6 carbon atoms with a peroxide selected from the group consisting of hydrogen peroxide, trifluoroperacetic acid, perbenzoic acid, monochloroperbenzoic acid, monoperphthalic acid, tertiary butylhydroperoxide and di-tertiary butyl peroxide, in the presence of an alkaline substance at a temperature of about -30 to 40.degree. C to obtain a 4,5-epoxy-3-oxotetrahydropyran derivative represented by the formula ##STR7## wherein R.sub.1 and R.sub.2 are as defined above, and (2) heating the 4,5-epoxy-3-oxotetrahydropyran derivative in the presence of an acid catalyst.
A process as defined in claim 11 wherein the heating temperature is in the range of about 50.degree. to 100.degree. C.
Dependencies are inferred from the claim text.