Formaldehyde → 3-(Dimethylaminomethyl)-7-azaindole

Participants

Reaction Steps

A mixture of 1H-pyrrolo[2,3-b]pyridine (18.07 g, 0.153 mol), dimethylamine hydrochloride (13.11 g, 0.161 mol) and paraformaldehyde (4.92 g, 0.164 mol) in n-butanol (500 ml) was heated at reflux for 35 minutes. The mixture was allowed to cool overnight and the precipitated solid collected by filtration. The filtrate was evaporated and the residue triturated with ethyl acetate to afford a second solid. The solids were combined, suspended in saturated aqueous potassium carbonate solution (500 ml) and extracted with dichloromethane (twice). The combined extracts were washed with saturated potassium carbonate (250 ml) then saturated sodium chloride solution (500 ml), dried (magnesium sulphate) then evaporated to a small volume, with the product crystallising out of solution during evaporation. Diethyl ether was added and the title compound collected as a solid (18.13 g, 67%). 1H NMR (360 MHz, DMSO-d6) δ2.19 (6H, s), 3.61 (2H, s), 7.03 (1H, dd, J1 =5, J2 =8 Hz), 7.36 (1H, d, J=2 Hz), 8.00 (1H, dd, J1 =2, J2 ==8 Hz), 8.20 (1H, dd, J1 =2, J2 =5 Hz), 11.47 (1H, broad s).

Provenance & Evidence