反应详情

Analogous to the preparation of 5-(2-chloropyridin-3-yl)-1H-indazole,5-(2-chloropyridin-3-yl)-1-methyl-1H-indazole was prepared by heating the mixture of 5-bromo-1-methyl-1H-indazole (1.0 g, 4.7 mmol), 2-chloro-3-pyridine boronic acid pinacol ester (1.2 g, 5.2 mmol), Pd(PPh3)4 (270 mg, 0.23 mmol) and 2M aq. Na2CO3 (6 mL, 12 mmol) in 1,4-dioxane (75 mL) under argon atmosphere for 12 h. Upon work-up as discussed in the preparation of 5-(2-chloropyridin-3-yl)-1H-indazole and purification of the concentrate by flash silica gel column chromatography [Combiflash® companion System® with RediSep® silica gel column 40 g, 30-50% EtOAc/hexanes eluting solvent gradient upon dry loading the concentrate absorbed on silica gel] provided 5-(2-chloropyridin-3-yl)-1methyl-1H-indazole as white solid (0.84 g, 73%). 1H NMR (DMSO-d6): δ 8.41 (dd, 1H, J=1.7 and 4.7 Hz), 8.10 (s, 1H), 7.90 (dd, 1H, J=1.7 and 7.6 Hz), 7.83 (app t, 1H, J=0.6 Hz), 7.72 (dd, 1H, J=0.6 and 8.8 Hz), 7.51 (dd, 1H, J=4.7 and 7.6 Hz), 7.48 (dd, 1H, J=1.7 and 8.8 Hz), 4.07 (s, 3H).LCMS: rt 6.73 min (A), purity 99%, MS (m/e) 244 (MH+).

1. customwas prepared
2. temperatureby heating
3. concentrationconcentrate by flash silica gel column chromatography [
4. customupon dry loading the concentrate
5. customabsorbed on silica gel]