METHOD FOR PRODUCING 4-METHYLCYCLOPENTENONE DERIVATIVE

摘要

PROBLEM TO BE SOLVED: To provide a new compound 4-methyl-2-cyclopenten-1-one-5-carboxylic acid ester derivative useful as an intermediate for medicines, a method for producing the same, a new compound 2-halo-4-methylcyclopentan-1-one-5- carboxylic acid ester derivative which is a synthetic intermediate therefor and a method for producing the same. SOLUTION: The 4-methyl-2-cyclopenten-1-one-5-carboxylic acid ester derivative is produced as follows. A 3-methylcyclopentan-1-one-2-carboxylic acid ester derivative readily preparable from a raw material derived from a relatively inexpensive and easily available natural product is halogenated to thereby produce the 2-halo-4-methylcyclopentan-1-one-5-carboxylic acid ester derivative. The resultant derivative is further passed through a dehydrohalogenation reaction thereof. COPYRIGHT: (C)2004,JPO