Chloroacetone → 2-Methylindolizine

Participants

Reaction Conditions

Reaction Steps

A mixture of α-picoline (5 g, 53.8 mmol) and chloroacetone (5 g, 53.8 mmol) was heated at 90-100° C. for 4 h. The reaction mixture was then poured into a chloroform/water mixture (50:50 mL) and subsequently extracted. The aqueous phase was treated with 0.6 g of sodium bicarbonate and then extracted with diethyl ether (3×30 mL) to remove the residual α-picoline. A further 8.1 g (96.4 mmol) of sodium bicarbonate were added to the aqueous phase, and the mixture was concentrated to give a mixture of white precipitate and water. Extracting the mixture with diethyl ether gave 5.6 g of 2-methylindolizine 1 in the form of white crystals; m.p.: 57-58° C. 1H NMR (CDCl3): δ 7.77-7.74 (m, 1H), 7.23 (d, J=8.9 Hz, 1H), 7.06 (s, 1H), 6.58-6.53 (m, 1H), 6.36-6.31 (m, 1H), 6.21 (s, 1H), 2.31 (s, 3H), 13C NMR (CDCl3): δ 132.8, 124.8, 124.6, 118.2, 116.5, 111.1, 109.4, 99.7, 12.4.

Provenance & Evidence