(S)-2-Carboxyethyl L-cysteinyl sulfone

Abstract

The title compound {systematic name: (2S)-2-azaniumyl-3-[(2-carboxyethane)sulfonyl]propanoate}, C6H11NO6S, forms enantiopure crystals in the monoclinic space group P21 and exists as a zwitterion, with a protonated α-amino group and a deprotonated α-carboxyl group. Both the carboxyl groups and the amino group are involved in an extensive multicentered intermolecular hydrogen-bonding scheme. In the crystal, the diperiodic network of hydrogen bonds propagates parallel to (101) and involves interconnected heterodromic R 4 3(10) rings. Electrostatic forces are major contributors to the structure energy, which was estimated by DFT calculations as E total = −333.5 kJ mol−1.