Crystal Growth, Single Crystal Structure, and Biological Activity of Thiazolo-Pyridine Dicarboxylic Acid Derivatives

[Image: see text] Four novel TPDCA derivatives were prepared via a supersaturation method combining TPDCA with water, N-methyl-2-pyrrolidone (NMP), Na(PO(2)H(2)), and ammonia solution: 2(C(9)H(7)NO(5)S)H(2)O (1), (C(9)H(7)NO(5)S)C(5)H(9)NO (2), (C(9)H(7)NO(5)S)Na(PO(2)H(2)) (3), and (C(9)H(5)NO(5)S)(NH(4))(2)(H(2)O) (4). Their crystal structures were determined by single-crystal X-ray diffraction. Compounds (1) and (2) crystallize in the monoclinic space groups P2(1) and P2(1)/c, respectively, whereas compounds (3) and (4) crystallize in the triclinic space group P1̅. Weak and moderate hydrogen bonds were detected in the four compounds. In the biological tests, (1) and (3) exhibited significant antibacterial activity against Escherichia coli and Staphylococcus aureus; in addition, (1) was cytotoxic against leukemia HL-60 cells with the IC(50) value of 158.5 ± 12.5 μM.