Chloroacetone → 2-Methylindolizine

Temperature

95 °C

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.

1. extractionsubsequently extracted
2. additionThe aqueous phase was treated with 0.6 g of sodium bicarbonate
3. extractionextracted with diethyl ether (3×30 mL)
4. customto remove the residual α-picoline
5. concentrationthe mixture was concentrated
6. customto give
7. extractionExtracting the mixture with diethyl ether

ORD record

ord-580fcc2ba20547b9be469703835b07cb

Source dataset

uspto-grants-2010_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07776107B2