Ethanol → 4-(4-(furan-3-yl)phenoxy)benzenesulfonyl-tetrahydro-2H-1,4-thiazine-3-carboxylic acid

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Reaktionsschritte

A mixture of 0.45 g (1.0 mmol) of 3(S)-4-(4-(4-bromophenoxy)benzenesulfonyl-tetrahydro-2H-1,4-thiazine-3-carboxylic acid and 0.11 g (1.0 mmol) of 3-furan boronic acid (J. Org. Chem. 1984, 49, 5237-5243) in 2 mL of benzene, 2 mL of 2M aq. sodium carbonate, and 1.5 mL of ethanol was deoxygenated with a stream of argon for 15 minutes, and then 115 mg (0.1 mmol) of tetrakis(triphenylphosphine)palladium was added and the mixture was heated at 80° C. for six days. After cooling to room temperature, the mixture was partitioned between ethyl acetate and pH 4 citrate buffer. The aqueous layer was extracted twice with ethyl acetate, and the combined organic layers were washed with brine, dried over sodium sulfate, and concentrated. The residue was purified by chromatography on silica gel, eluting with a gradient from dichloromethane to 5% methanol in dichloromethane, to provide 3(S)-4-(4-(4-(furan-3-yl)phenoxy)benzenesulfonyl-tetrahydro-2H-1,4-thiazine-3-carboxylic acid (0.317 g, 67%) as a sticky solid foam. FAB+MS Calcd for M+Cs+=606.0021. Obs 606.0036; 1H NMR (CDCl3) δ 7.72-7.43 (m, 6H), 7.04 (d, 2H, J=8.46 Hz), 7.00 (d, 2H, J=8.82 Hz), 6.67 (s, 1H), 4.51 (s, 1H), 4.1-3.9 (bm, 1H), 3.7-3.6 (bm, 1H), 3.2-3.1 (bm, 1H), 2.42 (bd, 1H, J=12.87 Hz), 1.61 (s, 3H), 1.38 (s, 3H)

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