PROBLEM TO BE SOLVED: To provide a novel method for producing a lactone compound as an intermediate of biotin that can increase a yield of a lactone compound as an intermediate of biotin and operability during the production of the lactone compound.SOLUTION: The method for producing a lactone compound represented by the formula as given below comprises cyclizing an amide alcohol compound represented by the formula as given below in the presence of hydrogen chlorine in a solvent including an alkylene glycol monoalkyl ether having the total carbon number of 2 to 12 in the molecule.SELECTED DRAWING: NoneCOPYRIGHT: (C)2018,JPO&INPIT【課題】ビオチンの中間体であるラクトン化合物の収率、および該ラクトン化合物を製造する際の操作性を向上できる、該中間体の新規な製造方法の提供。【解決手段】塩化水素の存在下、下記式で示されるアミドアルコール化合物を、分子中の全炭素数が２～１２のアルキレングリコールモノアルキルエーテルを含む溶媒中で環化させることにより、下記式で示されるラクトン化合物を製造する方法である。【選択図】なし
