Pyridine → 4-Vinylbenzoic acid 2-thioxo-oxazolidin-4-ylmethyl ester

A solution of 4-vinylbenzoyl chloride (21.0 g, 126 mmol) in dry THF (50 mL) was added to a solution of 4-hydroxymethyl-1,3-oxazolidine-2-thione (14.0 g, 105 mmol) in dry THF (250 mL) and pyridine (10.2 mL, 126 mmol) at 0° C. After 12 hours of stirring at room temperature, pyridine hydrochloride was filtered off, and the solvent was evaporated out in vacuo. The residue was purified by silica gel column chromatography eluted with ethyl acetate/acetone (1/1=v/v), followed by recrystallization from a mixed solvent [n-hexane/ethyl acetate (3/1=v/v)] to afford 4-vinylbenzoic acid 2-thioxo-oxazolidin-4-ylmethyl ester as a colorless solid. Yield 73% (24.1 g, 91.5 mmol). 1H NMR (DMSO-d6): δ=4.25–4.77 (5H, >CH—, —CH2—O(CO)—, and —(SC)O—CH2—), 5.45 (d, J=10.8 Hz, 1H, —CH═CH2), 6.03 (d, J=17.8 Hz, 1H, —CH═CH2), 6.84 (dd, J=11.3 and 17.7 Hz, 1H, —CH═CH2), 7.64 (d, J=8.1 Hz, 2H, —C6H4—), 8.01 (d. J=8.1 Hz, 2H, —C6H4—), 10.3 (broad s, 1H, —NH—) ppm. 13C NMR (DMSO-d6): δ=55.0 (CO—CH2—CH<), 65.1 (>CH—), 71.8 (—CH2—O(CO)—), 117.7 (—CH═CH2), 126.5, 128.6, 130.1 (—C6H4—), 136.0 (—CH═CH2), 142.2 (—C6H4—), 165.6 (—O(CO)—C6H4—), 189.3 (>C═S) ppm. IR (KBr): 3185, 1712 (—OCOPh), 1504 (C═S), 1280, 1180, 1110, 971 cm−1.