hydroxylamine-O-sulfonic acid → HCID 16102687, compound

Participants

Reaction Steps

A solution of sodium bicarbonate (316.9 mg, 3.77 mmol) in water (7.5 mL) is added to a solution of ethyl 7-bromo-1-cyclopropyl-2-mercapto-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylate (from above, ˜0.37 mmol) in tetrahydrofuran (7.5 mL) at room temperature. Hydroxylamine-O-sulfonic acid (214.7 mg, 1.90 mmol) is added as a solid and in one portion to this mixture. The resulting amber solution is stirred at room temperature for 2.5 h and quenched by addition of an aqueous solution of 5% hydrochloric acid (50 mL). The solid that formed is collected by filtration, washed with an aqueous solution of 5% hydrochloric acid (3×10 mL), washed with distilled water (3×10 mL), and dried in vacuo to give 17 as a tan solid. This product ids of sufficient purity (≧95% by 1H NMR spectroscopy) to use directly in the next synthetic step. 1H NMR (DMSO-d6): δ 1.00 (m, 2H, c-Pr CH2), 1.20 (m, 2H, c-Pr CH2), 3.79 (s, 3H, OCH3), 3.85 (m, 1H, c-Pr CH), 7.66 (d, J=8.5 Hz, 1H, aromatic H-6), 7.93 (d, J=8.5 Hz, 1H, aromatic H-5), 11.67 (br, 1H). 13C{1H} NMR (DMSO-d6): δ 11.5 (c-Pr CH2), 35.1 (c-Pr CH), 61.9 (OCH3), 107.7, 122.9 (CH, C-5), 123.5 (C—Br, C-7), 127.9 (CH, C-6), 128.0 (C-4a), 136.5 (C-8a), 146.6 (C—OCH3), 164.5, 171.1 (C═O, C-4), 171.2 (br). LCMS m/z calcd for C14H1179BrN2O3S ([M]+) 366. Found 367 ([M+H]+). HRMS m/z calcd for C14H1179BrN2NaO3S 388.9571 ([M+Na]+). Found 388.9577.

Provenance & Evidence