Sodium Dithionite → HCID 58344958, compound

Participants

Reaction Conditions

Reaction Steps

tert-butyl 4-((5-bromo-3-nitropyridin-2-yl)amino)benzylcarbamate (25.0 g, 58.9 mmol), 2-aminonicotinaldehyde (10.2 g, 83.5 mmol), sodium dithionite (31.0 g, 178 mmol), methanol (80 mL), and DMSO (500 mL) were placed in a round-bottomed flask which was allowed to stir at 100° C. for 36 h. After cooling to room temperature the mixture was diluted with ethyl acetate (500 mL) and water (500 mL). The layers were separated, the organic layer was washed with water (2×300 mL) and concentrated to yield the crude product as a black oily solid (29.2 g). Column chromatography (1-5% methanol in dichloromethane) yielded an orange solid which could be further purified by re-crystallization (ethyl acetate/hexanes, 1:1) to yield tert-butyl 4-(2-(2-aminopyridin-3-yl)-6-bromo-3H-imidazo[4,5-b]pyridine-3-yl)benzylcarbamate (11.8 g, 23.8 mmol, 41%) as an off-white solid. Mp. 176-178° C.; 400 M Hz 1H NMR (DMSO-d6) δ: 8.50 (d, J=2.0 Hz, 1H), 8.40 (d, J=2.4 Hz, 1H), 7.99 (dd, J=2.0 Hz and 4.7 Hz, 1H), 7.48 (t, J=5.6 Hz, 1H), 7.40-7.31 (m, 3H), 7.23 (dd, J=2.0 Hz and 7.8 Hz, 1H), 6.97 (s, 2H), 6.40 (dd, J=4.4 Hz and 7.7 Hz, 1H), 4.121 (d, J=6.2 Hz, 2H), 1.41 (s, 9H), MS 495.34, 497.23 [M+H, M+2+H].

Provenance & Evidence