反应详情

To a mechanically stirred suspension of (6-methyl-2-p-tolyl-imidazo[1,2-a]pyridin-3-yl)-acetic acid 1a (5.0 g, 17.9 mmol) in THF (50 ml) at 0° C. under nitrogen atmosphere was added dropwise a 1.0 M solution of borane-tetrahydrofuran complex (56 ml, 56 mmol). The mixture was slowly warmed to ambient temperature and stirred for 2 h (nearly homogeneous at this point, slightly hazy). The reaction was quenched with 1.0 N HCl at 0° C., and stirred at ambient temperature for 0.5 h. The solution was concentrated in vacuo in order to remove the volatiles. The resulting solution was basified at 0° C. with 10% NaOH and extracted with dichloromethane (2×250 ml). The organic layers were combined, dried (Na2SO4), and concentrated to afford 4.4 g (93%) of product as a white solid. 1H NMR (400 MHz, CDCl3) δ 1.80 (broad s, 1H), 2.29 (s, 3H), 2.37 (s, 3H), 3.21 (t J=6.2 Hz, 2H), 4.00 (t, J=6.2 Hz, 2H), 6.82 (dd, J=1.5, 8.8 Hz, 1H), 7.14 (d, J=8.0 Hz, 2H), 7.29 (d, J=9.1 Hz, 1H), 7.58 (d, J=8.0 Hz, 2H), 7.84 (s, 1H).

1. customThe reaction was quenched with 1.0 N HCl at 0° C.
2. stirringstirred at ambient temperature for 0.5 h
3. concentrationThe solution was concentrated in vacuo in order
4. customto remove the volatiles
5. customwas basified at 0° C. with 10% NaOH
6. extractionextracted with dichloromethane (2×250 ml)
7. dry with materialdried (Na2SO4)
8. concentrationconcentrated