To a 0° C. solution of N-methylbenzothiohydrazide (10 mmol) in DCM (20 mL) and pyridine (1 mL) was added 2-(chlorosulfonyl)acetyl chloride (5 mmol) dropwise. The mixture was kept at rt for 2 h before it was poured into water (20 ml). The organic layer was separated, dried and evaporated and the resulting residue was purified by column chromatography to give compound 68 as yellowish solids (0.8 g). 1H-NMR (CDCl3) δ 10.5 (m, 1H), 7.4 (m, 10H), 4.4 (m, 1H), 3.4-3.8 (m, 8H) ppm; ESMS calcd for C18H20N4O3S3:436.1; found: 437.2 (M+H+).
