| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing 4-chromanones and 4-thiochromanones useful as a synthetic intermediate of pharmaceuticals and agrochemicals, inexpensively and easily in a high yield, by the dehydration cyclization of 3-phenoxypropionic acids and 3-phenylthiopropionic acids, respectively. SOLUTION: The method for manufacturing the 4-chromanones and the 4-thiochromanones represented by general formula (III) comprises causing a carboxylic acid represented by general formula (I) to cyclize in the presence of a catalytic amount of a Lewis acid represented by general formula (II) MXm-Ln. In general formulae (I) and (III), R<SP>1</SP>-R<SP>8</SP>are each a group not participating in the reaction; and A is an oxygen or sulfur atom. In general formula (II), M is a metal ion selected from among Bi, Ga, In, Hf and rare earth elements; X is an anion; L is a neutral molecule having coordinating force to M; m is a valence number of the metal M; and n is an integer of 0-10. COPYRIGHT: (C)2004,JPO&NCIPI
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