Patent ID: 8173802

Claim:
A method for producing a piperidin-4-one derivative represented by formula (III-a) or formula (III-b), (wherein R represents benzyl group, R 2 and R 4 each independently represents a hydrogen atom or an organic group, R 11 and R 12 each independently represents a hydrogen atom, hydrocarbon group, acyl group or heterocyclic group, and R 11 and R 12 may together form ethylene group, and X means an alkylene group having 2 to 5 carbons), wherein the method comprises allowing ethyleneglycol to react with benzylamine so as to produce 3-benzyl-[1,5,3]dioxazepane, then allowing 3-benzyl-[1,5,3]dioxazepane to react with an acetone derivative represented by formula (II) (wherein R 2 , R 4 and X mean the same as above), in the presence of at least one substance selected from the group consisting of a protonic acid, Lewis acid, acid halide and dialkyl sulfate.