Methyl 2-(5-methyl-3-methyl-sulfinyl-1-benzofuran-2-yl)acetate.

The title compound, C(13)H(14)O(4)S, was prepared by oxidation of methyl 2-(5-methyl-3-methyl-sulfanyl-1-benzofuran-2-yl)acetate with 3-chloro-peroxy-benzoic acid. The O atom and methyl group of the methyl-sulfinyl substituent lie on opposite sides of the plane of the benzofuran system. The crystal structure is stabilized by inter-molecular aromatic π-π inter-actions between the benzene rings of neighbouring mol-ecules, with a centroid-centroid separation of 3.841 (3) Å.