Hydroxyamine hydrochloride → 2-bromo-6,7-dihydro-1H-indol-4(5H)-one oxime

関与物質

反応手順

A solution of 2-bromo-6,7-dihydro-1H-indol-4(5H)-one (303a) (222 mg, 1.04 mmol), hydroxylamine hydrochloride (80 mg, 1.14 mmol), and sodium acetate (94 mg, 1.14 mmol) in MeOH (28 mL) was stirred under argon at 50° C. for 22 h. The reaction mixture was then concentrated in vacuo, and the residue was partitioned between saturated aq. NaHCO3 (40 mL) and EtOAc (60 mL). The organic layer was separated, and the aq. layer was extracted with EtOAc (60 mL). The combined extracts were dried over Na2SO4, filtered, and concentrated in vacuo to provide 2-bromo-6,7-dihydro-1H-indol-4(5H)-one oxime (273 mg) as an off-white solid. 1H NMR (400 MHz, CDCl3) δ ppm: (˜2:1 mixture of oxime isomers) Major isomer: 7.99 (1H, br. s.), 6.36 (1H, br. s.), 2.71 (2H, br. s.), 2.63 (2H, br. s.), 1.89-1.98 (2H, m). Minor isomer: 1H NMR (400 MHz, CDCl3) δ ppm 8.14 (1H, br. s.), 6.97 (1H, br. s.), 2.67-2.75 (2H, m), 2.47 (2H, br. s.), 1.99 (2H, br. s.). m/z (ESI, +ve) 228.9/231.1 (M+H)+.

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