Hydrochloric Acid → 9-Bromo-5-methylsulfonyloxymethyl-6,7-dihydro-1H, 5H-pyrido[1,2,3-de]quinoxaline-2,3-dione

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Reaction Conditions

Reaction Steps

To a solution of 9-bromo-5-hydroxymethyl-6,7-dihydro-1H, 5H-pyrido[1,2,3-de]quinoxaline-2,3-dione (3 g, 9.65 mmol) and triethylamine (1,28 g, 12.67 mmol) in THF (200 mL) was added methanesulfonyl chloride (1.44 g, 12.57 mmol) at -20° C. The mixture was stirred for 1.5 h at the same temperature and triethylamine (0.6 mL) and methanesulfonylchloride (0.4 mL) were added. The mixture was further stirred for 1 h at -20° C. and for 30 min at 0° C. and poured into water (500 mL). The mixture was acidified with 3N hydrochloric acid and extracted with ethyl acetate (500 mL×3). The organic layers were washed with brine, dried over magnesium sulfate, and concentrated. The residue was purified by silica gel column chromatography with 1 to 5% acetic acid/ethyl acetate to give 2.42 g of the title compound (64%): mp 125°~130° C. (dec); 1H NMR (270 MHz, DMSO-d6) δ12.05 (bs, 1H), 7.20 (s, 1H), 7.15 (s, 1H), 4.97~5.06 (m, 1H), 4.28 (d, 2H, J=7.5 Hz), 3.20 (s, 3H), 2.97 (ddd, 1H, J=17.1, 13.5, 4.5 Hz), 2.83 (dm, 1H, J=17.1 Hz), 2.27 (dm, 1H, J=13.5 Hz), 1.81~1.97 (m, 1H).

Provenance & Evidence