m-Chloroperbenzoic acid → 5-[(2-Ethoxycarbonylethyl)thio]-4-hydroxymethyl-1,2,3-thiadiazole

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Reaction Steps

To a solution of 5-[(2-ethoxycarbonylethyl)thio]-4-[(2-ethoxycarbonylethyl)thiomethyl]-1,2,3-thiadiazole (1.0 g, 3.0 mmol) in dichloromethane (40 mL) was added m-chloroperoxybenzoic acid in several portions at 0° C. until the starting material was disappeared. The mixture was then sequentially washed with saturated aqueous sodium thiosulfate, cold aqueous 1% sodium hydroxide and brine, and was concentrated to dryness. The oxidized product was treated with trifluoroacetic anhydride (2 mL) for 30 min at room temperature. After removal of trifluoroacetic anhydride under the reduced pressure, the mixture was stirred in ethyl acetate/1% sodium hydroxide (30 ml/30 mL) for 30 min. The ethyl acetate layer was concentrated to a volume of 5 mL and methanol (10 mL) was added. Excess sodium borohydride (200 mg) was added in portions at 0° C. while stirring. After 30 min, the reaction was quenched with diluted hydrochloric acid. The mixture was extracted with ethyl acetate and concentrated. The residue was purified by silica gel chromatography (1% methanol/dichloromethane) to provide 225 mg of 5-[(2-ethoxycarbonylethyl)thio]-4-hydroxymethyl-1,2,3-thiadiazole. 1H NMR (CDCl3) δ 1.27 (t, 3H, J=8), 2.71 (t, 2H, J=7), 3.27 (t, 2H, J=7), 4.16 (q, 2H, J=8), 5.03 (s, 2H).

Provenance & Evidence