(4R)-(−)-2-Thioxothiazolidine-4-carboxylic Acid (Raphanusamic Acid)

The title acid, C₄H₅NO₂S₂, crystallized in the non-centrosymmetric space group P2₁2₁2₁ with one molecule as the asymmetric unit. Two hydrogen bonds occur, namely, N—H...O, with a donor–acceptor distance of 2.850 (2) Å, and O—H...S (resonance induced), with a donor–acceptor distance of 3.318 (2) Å; both H atoms involved are ordered. These two types of bonds link a given molecule to four neighbors, the molecules linked being of space-group symmetry types 1 and 3, or 2 and 4. These two subsets of molecules alternate in layers along c. Three significant C—H...O interactions occur, one of which crosslinks the subsets just described to produce a three-dimensional network of linked molecules. The absolute structure is determined.

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