(Z)-5-(3,4,5-Trimethoxystyryl)-2,3-dihydrothieno[3,4-b][1,4]dioxine

Abstract

In the title compound, C17H18O5S, an analogue of the potent anticancer agent combretastatin A-4, the alkene C=C bond has a cis conformation and the C—C=C—C torsion angle is 9.0 (3)°. The dihedral angle between the benzene and thiophene rings is 54.07 (4)°. The dioxene ring adopts a half-chair conformation, with the C atoms of the methylene groups displaced by −0.325 (2) and 0.341 (3) Å from the plane of the other atoms. The C atoms of the two meta-methoxy groups are close to being coplanar with their attached benzene ring [displacements = −0.025 (2) and −0.196 (2) Å], whereas the C atom of the para-methoxy group is significantly displaced [by −1.107 (2) Å]. In the crystal, C—H...O hydrogen bonds link the molecules into [0-11] chains, which feature two different types of R22(6) loops.