Acetone → 2,4Dimethyl-3-acetyl-5-isopropyl pyrrole

Participants

Reaction Steps

Aqueous hydriodic acid (10 ml) and 2 ml of 50% hypophosphorous acid were cooled and stirred while 10 ml of acetic anhydride was slowly added. 2,4-Dimethyl-3-acetyl-pyrrole (548 mg) was dissolved in the solution, 0.6 ml of acetone added, and the mixture was stirred for 1/2 hr. by which time a yellow precipitate had formed and redissolved and the solution had turned yellow; the final temperature was 37° C. It was poured into 100 ml of water and 30 ml of ammonium hydroxide kept at 20° C. The nearly colourless product separated as plates (662 mg, 92%). At 138° C. these changed to cubes which either melted at 165° C. or turned to irregular needles, m.p. 171°-173° C. For analysis, it was recrystallized from aqueous ethanol as colourless plates, m.p. 165.5° C. or 171.5°-173° C.

Provenance & Evidence