Crystal structure of 5-{4′-[(2-{2-[2-(2-ammonioethoxy)ethoxy]ethoxy}ethyl)carbamoyl]-4-methoxy-[1,1′-biphenyl]-3-yl}-3-oxo-1,2,5-thiadiazolidin-2-ide 1,1-dioxide: a potential inhibitor of the enzyme protein tyrosine phosphatase 1B (PTP1B)

The title compound, C24H32N4O8S, (I), crystallizes as a zwitterion. The terminal amine N atom of the [(2-{2-[2-(2-ammonioethoxy)ethoxy]ethoxy}ethyl)carbamoyl] side chain is protonated, while the 1,2,5-thiadiazolidin-3-one 1,1-dioxide N atom is deprotonated. The side chain is turned over on itself with an intramolecular N—H...O hydrogen bond. The 1,2,5-thiadiazolidin-3-one 1,1-dioxide ring has an envelope conformation with the aryl-substituted N atom as the flap. Its mean plane is inclined by 62.87 (8)° to the aryl ring to which it is attached, while the aryl rings of the biphenyl unit are inclined to one another by 20.81 (8)°. In the crystal, molecules are linked by N—H...O and N—H...N hydrogen bonds, forming slabs lying parallel to (010). Within the slabs there are C—H...O and C—H...N hydrogen bonds and C—H...π interactions present.