2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → methyl (5R)-3-[4-(1,1-dioxido-2,3-dihydro-4H-1,4-thiazin-4-yl)-3,5-difluorophenyl]-2-oxo-5-oxazolidinecarboxylate

Participants

Reaction Steps

A solution of methyl (5R)-3-[4-(1,1-dioxidothiomorpholin-4-yl)-3,5-difluorophenyl]-2-oxo-5-oxazolidinecarboxylate (Step 2, 0.73 g, 1.87 mmol) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (1.27 g, 5.6 mmol) in dioxane (9 mL) is heated to 100° C. for two days. The solution is cooled and treated with 20 mL of 10% aqueous Na2SO3 and stirred for 30 minutes. The solution is then diluted with water and extracted three times with ethyl acetate. The combined organic phases are washed with satd NaHCO3 and saline and dried (MgSO4), filtered and concentrated. The crude residue is purified by column chromatography (0→5% ethyl ether-dichloromethane) to provide the title compound (0.28 g, 38%); 1H NMR (300 MHz, CDCl3): δ 3.31–3.35 (m, 2H), 3.89 (s, 3H), 4.00–4.15 (m, 3H), 4.25 (t, 1H), 5.11 (m, 1H), 5.45 (d, 1H), 6.54 (d, 1H), 7.29 (d, 2H).

Provenance & Evidence