Carbon Dioxide → 76369-00-1

Participants

Reaction Steps

Lit. Tetrahedron, 41:5633 (1985). To a stirred solution of 10.0 g (90.0 mmol) pyrrole-2-carboxylic acid in 180 ml dioxane was added dropwise at 0° C. 18 ml concentrated sulphuric acid 2-methylpropene was then condensed into the reaction flask over the course of 1 h, using a dry-ice condenser, and stirring continued for 16 h at 0° C. while the dry-ice condenser was periodically refilled so as to maintain a slow reflux of 2-methylpropene. The reaction mixture was then poured cautiously into an ice cooled mixture of 400 ml ether and 150 ml 2 M sodium hydroxide solution. The phases were separated and the aqueous phase extracted twice more with ether. The combined organic phases were washed successively with 2 M sodium hydroxide solution, water and finally with saturated brine, then dried over sodium sulphate and concentrated in vacuo to afford 9.07 g (60%) of the title compound as a colorless oil which still contained some dioxane. 1H NMR d (250 MHz, CDCl3) 9.60 (1H, br s), 6.90 (1H, m), 6.83 (1H, m), 6.22 (1H, m), 1.56 (9H, s).

Provenance & Evidence