Acetic Acid → 5-[4-(2-Hydroxy-2-phenylethoxy)benzyl]-1,3-thiazolidine-2,4-dione

Participants

Reaction Steps

To a mixture of 5-[4-(2-hydroxy-2-phenylethoxy)benzylidene]-1,3-thiazolidine-2,4-dione (1.50 g, 4.39 mmol) in THF (20 ml) was added H2O (20 ml), 1M NaOH (3 ml), cobalt (II) chloride hexahydrate (0.60 mg, 0.003 mmol) and dimethylglyoxime (15 mg, 0.13 mmol). A solution of sodium tetrahydroborate (240 mg, 6.33 mmol) in 0.2M NaOH (3.6 ml) was added. The reaction mixture immediately turned dark but very soon assumed a clear yellow appearance. Acetic acid was added dropwise until the solution turned dark (3 drops). After ca. one hour the reaction lightened. Additional NaBH4, CoCl2 and HOAc were added to produce a deep blue-purple color. When that color faded, more NaBH4 was added. When HPLC analysis indicated that the reaction was complete, it was partitioned between H2O and EtOAc, and the organic phase was washed with brine, dried (Na2SO4), filtered and evaporated in vacuo. The resulting foamy solid was chromatographed, eluting with 50% EtOAc/hexanes. Fractions containing product were combined and evaporated in vacuo to give 1.15 g (76%) of the title compound as a white solid. MS (ESI−) for C18H17NO4S m/z 342.1 (M−H)−.

Provenance & Evidence