Hydroxyamine hydrochloride → 2-[3-(tert-butylamino)-2-[(E)-hydroxyiminomethyl]quinoxalin-5-yl]-1,5,6,7-tetrahydropyrrolo[3,2-c]pyridin-4-one

Participants

Reaction Steps

A solution of 3-(tert-butylamino)-5-(4-oxo-4,5,6,7-tetrahydro-1H-pyrrolo[3,2-c]pyridin-2-yl)quinoxaline-2-carbaldehyde (307b) (44.0 mg, 0.12 mmol), hydroxylamine hydrochloride (11.7 mg, 0.17 mmol), and TEA (0.024 mL, 0.17 mmol) in MeOH (5.0 mL) was stirred at 60° C. for 1.5 h. The reaction mixture was subsequently cooled to RT, diluted with saturated aq. NaHCO3 (20 mL), and extracted with 5% MeOH/DCM (2×30 mL). The combined extracts were sequentially washed with water (30 mL) and brine (20 mL), dried over Na2SO4, filtered, and concentrated onto silica gel. Chromatographic purification (silica gel, 0-100% EtOAc/hexanes, then 0-10% MeOH/DCM) furnished (E)-3-(tert-butylamino)-5-(4-oxo-4,5,6,7-tetrahydro-1H-pyrrolo[3,2-c]pyridin-2-yl)quinoxaline-2-carbaldehyde oxime (31.0 mg, 0.082 mmol, 68% yield) as an orange solid: 1H NMR (400 MHz, DMSO-d6) δ ppm 12.34 (1H, br. s.), 11.86 (1H, br. s.), 8.34 (1H, s), 8.31 (1H, s), 7.91 (1H, dd, J=7.3, 1.1 Hz), 7.67 (1H, dd, J=8.0, 1.0 Hz), 7.40 (1H, t, J=7.8 Hz), 7.09 (1H, d, J=2.2 Hz), 6.95 (1H, br. s.), 3.43 (2H, td, J=6.8, 2.2 Hz), 2.86 (2H, t, J=6.8 Hz), 1.57 (9H, s). m/z (ESI, +ve) 379.1 (M+H)+.

Provenance & Evidence