3-(2H-1,3-Benzodioxol-5-ylmethyl)-2-(2-methoxyphenyl)-1,3-thiazolidin-4-one

The title molecule, C18H17NO4S, features a 1,3-thiazolidine ring that is twisted about the S—C(methylene) bond. With reference to this ring, the 1,3-benzodioxole and benzene rings lie to either side and form dihedral angles of 69.72 (16) and 83.60 (14)°, respectively, with the central ring. Significant twisting in the molecule is confirmed by the dihedral angle of 79.91 (13)° formed between the outer rings. Linear supramolecular chains along the a-axis direction mediated by C—H⋯O interactions feature in the crystal packing.

The title molecule, C 18 H 17 NO 4 S, features a 1,3-thiazolidine ring that is twisted about the S-C(methylene) bond. With reference to this ring, the 1,3-benzodioxole and benzene rings lie to either side and form dihedral angles of 69.72 (16) and 83.60 (14) , respectively, with the central ring. Significant twisting in the molecule is confirmed by the dihedral angle of 79.91 (13) formed between the outer rings. Linear supramolecular chains along the a-axis direction mediated by C-HÁ Á ÁO interactions feature in the crystal packing.
The use of the EPSRC X-ray crystallographic service at the University of Southampton, England, and the valuable assistance of the staff there is gratefully acknowledged. JLW acknowledges support from CAPES and FAPEMIG (Brazil).
The thiazolidinyl ring in (I), Fig. 1, is twisted about the S1-C3 bond but, the deviations from co-planarity for the five atoms are not great, i.e. the maximum and minimum deviations are 0.109 (1) Å for atom S1 and -0.117 (4) Å for atom C3; the ketone-O1 atom lies 0.244 (2) Å out of the least-squares plane through the five-membered ring. The dioxole ring has an envelope conformation with the C15 atom being the flap atom. The r.m.s. deviation for the 13 non-hydrogen atoms comprising the 1,3-benzodioxole ring is 0.110 Å. With reference to the thiazolidinyl ring, the 1,3-benzodioxole and benzene rings lie to either side and form dihedral angles with this ring of 69.72 (16) and 83.60 (14)°, respectively. The outer rings form a dihedral angle of 79.91 (13)° with each other, indicating that the molecule is highly twisted.
The most prominent feature of the crystal packing is the formation of C-H···O interactions involving the bifurcated carbonyl-O1 atom, Table 1. These lead to linear supramolecular chains along the a axis, Fig. 2.

Experimental
The title compound was synthesized as described in the literature (Neuenfeldt et al., 2011) and crystals were obtained from its EtOH solution.

Refinement
The C-bound H atoms were geometrically placed (C-H = 0.95-1.00 Å) and refined as riding with U iso (H) = 1.2U eq (C).