Diethyl trans-2,5-bis-(4-methoxy-benzyl-sulfan-yl)-1,4-dimethyl-3,6-dioxopiperazine-2,5-carboxyl-ate.

The title compound, C(28)H(34)N(2)O(8)S(2), was synthesized as part of a project to develop synthetic routes to analogues of sporidesmins, a class of secondary metabolite produced by the filamentous fungi Chaetomium and Pithomyces sp. The complete molecule is generated by crystallographic inversion symmetry: the methoxy group is essentially coplanar with the benzene ring to which it is bonded, a mean plane fitted through the non-H atoms of the aromatic ring and the meth-oxy group having an r.m.s. deviation of 0.0140 Å. Similarly, the ester group is also essentially planar (r.m.s. deviation of a plane fitted through all non-H atoms is 0.0101 Å). There is only one independent C-H⋯O inter-action, which links together adjacent mol-ecules into a two-dimensional sheet in the bc plane.