Hydrochloric Acid → 3-Carboxy-1,4-dimethyl-1H-pyrrole-2-acetic acid

Participants

Reaction Conditions

Reaction Steps

To 1200 parts of cold water (about 5° C.) there are added 292 parts of 3-oxo-pentanedioic acid and the reaction mixture is further cooled to -5° C. 1770 Parts of methanamine 35% in water are then added slowly while stirring and cooling to a temperature between -5° C. and 5° C. The reaction mixture is further cooled to about -15° C. Then 370 parts of 1-chloro-2-propanone are added portionwise under vigorous cooling. An exothermic reaction takes place and the temperature of the mixture raises to about 15° C. It is again cooled to about 0° C. and further stirred at this temperature for about 16 hours. The reaction mixture is then poured onto a mixture of 4000 parts of ice and 2200 parts of concentrated hydrochloric acid solution (10.5 N) and stirring is continued for 20 minutes. The product is filtered off and dried in vacuo at 50° C. over CaCl2, yielding 335 parts (85%) of 3-carboxy-1,4-dimethyl-1H-pyrrole-2-acetic acid, mp. 192.8°-194.6° C. dec.

Provenance & Evidence