| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject compound, by using a pyridine base as a reaction solvent for an intramolecular condensation reaction while suppressing precipitation of crystal of reaction product. SOLUTION: A nitrogen-containing di carboxylic acid diester [e.g. a compound of formula I (R<1> and R<2> are each an alkyl; (a) is 1, 2 or 3; (b) and (c) are each an integer of 0-4), etc.] is dripped in a base (an alkali metal alkoxide and an alkali hydride) and a pyridine base (2-methylpyridine, etc.) as a reaction solvent at 70-150 deg.C with stirring for 1-3 hours, stirred for 1-3 hours after the dripping and an intramolecular condensation reaction is carried out to give an enol type compound. A salt of the compound is subjected to salt decomposition with an acid (hydrochloric acid, etc.) to give the objectiveβ-ketoester. Further the reaction product mixture is added to an aqueous solution of an acid while maintaining the mixture at 5-30 deg.C and a prepared acidic mixture is kept at 90 deg.C to the reflux temperature to give the objective ketone (e.g. a compound of formula II).
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