Anomeric effects involving a carbon–sulphur bond: the X-ray crystal structure of methyl (Z)-2-methoxy-3-methyl-2-(N-methylanilino)-4-oxothiazolidin-5-ylidene-ethanoate

Abstract

In the X-ray crystal structure of the title compound (6) the C(2)–S(1) bond is antiperiplanar to two lone pairs from the 2-methoxy-and 2-(N-methylanilino)-groups and is lengthened to 1.880(2)Å. The second lone pair on the 2-methoxy oxygen atom is antiperiplanar to the endocyclic C–N bond. The crystallographic evidence for anomeric interactions between oxygen or nitrogen lone pairs and C–S bonds is discussed and the latter appear to be stronger. Crystal data for (6): C₁₅H₁₈N₂O₄S, M_r= 322.4, triclinic, P, a= 8.344(1), b= 10.045(5), c= 10.905(2)Å, α= 106.52(3), β= 109.99(1), γ= 97.10(2)°, Z= 2, D_c= 1.34 g cm^–3, µ(Mo-K_α)= 0.59 mm^–1, final R-value = 0.039 for 1 981 reflection with I3σ(I).