Ethyl bromopyruvate → 2,2-Dimethyl-3,4-dihydro-2H-[1,4]thiazine-3,5-dicarboxylic acid

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Reaction Steps

To a solution of L-penicillamine (298 mg, 2.0 mmol) in water (5 mL) and acetonitrile (5 mL) was added ethyl 3-bromopyruvate (0.25 mL, 390 mg, 2.0 mmol) slowly. To the resulted mixture was added sodium bicarbonate aqueous solution till the pH about 5. Acetonitrile was removed under vacuum and some more water was added. The solution was extracted with methylene chloride. The water phase was separated and freeze-dried under high vacuum. The residue was chromatographed (silica gel, methylene chloride-methanol-acetic acid 100:5:0.3 to 100:10:0.3) to give 150 mg of product (yield 31%). 1HNMR (300 Hz, D3COD) δ (ppm) 6.17 (s, 1H), 4.23 (q, J=7.1 Hz, 2H), 3.79 (s, 1H), 1.48 (s, 3H), 1.31 (t, J=7.1 Hz, 3H), 1.29 (s, 3H). 13CNMR (75 Hz, D3COD) δ (ppm) 173.8, 164.0, 128.0, 102.4, 64.1, 62.2, 41.2, 28.3, 25.2, 14.7 ppm. MS (ESI) m/z 268 (M+Na, 100), 246 (M+1, 5).

Provenance & Evidence