| 摘要 |
PROBLEM TO BE SOLVED: To produce an oxo-tetrahydrochroman-carboxylic acid compound which is an intermediate for a compound useful as an intermediate for medicines without producing by-products and without requiring extracting operations by reacting a specific cyclohexane-dione compound with a halogenopyruvic acid ester. SOLUTION: One mol of a cyclohexane-1 3-dione compound represented by formula I (R1 to R3 are each H or a hydrocarbon) is reacted with preferably 0.85-1.05 mol of a halogenopyruvic acid ester in the presence of a basic compound (e.g. sodium hydroxide) preferably at 5-30 deg.C and the resultant compound is then hydrolyzed and dehydrated to produce a 4-oxo-4,5,6,7- tetrahydrochroman-3-carboxylic acid compound represented by formula II. The amount of the basic compound used is preferably 0.95-1.05 equiv. based on the compound represented by formula I. The amount of an aqueous medium is preferably 300-400 pts.wt. based on 100 pts.wt. of the compound represented by formula I.
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