Dimethylamine → (6-Dimethylaminomethyl-imidazo[1,2-a]pyridin-3-yl)-acetic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

(6-Formyl-imidazo[1,2-a]pyridin-3-yl)-acetic acid ethyl ester (770 mg, 3.15 mmol) is dissolved in THF (10 ml) and treated with an excess of dimethylamine. The reaction mixture is stirred for 16 hours at room temperature in a stainless steel autoclave. A solution of sodium cyanoborohydride (229 mg, 3.46 mmol, 1.1 equiv) in MeOH (1.0 ml) and glacial acetic acid (1.1 ml) are added, and the solution is stirred for 1 hour at 60° C. The reaction mixture is diluted with water and adjusted to pH 8-9 by the addition of concentrated aqueous NaHCO3 solution. Extraction with EtOAc, washing with brine, drying over Na2SO4 and removal of solvent affords the crude reaction product. Purification via flash chromatography (EtOAc/cyclohexane 4:1, +0.2% NEt3) yields the title compound (242 mg, 29%). 1H NMR (400 MHz, CDCl3): δ=7.76-7.74 (m, 1H), 7.35 (dd, J=9.3/1.0 Hz, 1H), 7.31 (s, 1H), 6.99 (dd, J=9.1/1.7 Hz, 1H), 3.95 (q, J=7.1 Hz, 2H), 3.71 (s, 2H), 3.23 (s, 2H), 2.06 (s, 6H), 1.03 (t, J=7.1 Hz, 3H). MS (ES+): 262 (M+H)+.

Provenance & Evidence