Formaldehyde → 4,5,6,7-Tetrahydrothieno(3,2-c)pyridinium chloride

Participants

Reaction Conditions

Reaction Steps

100 gm. of 2-thienylethylamine was charged in a 1 liter reaction vessel equipped with a dean stark assembly for azeotropic removal of water. Dichloroethane (600 ml.) was added and the mixture stirred for 5 minutes. 26.4 gm. paraformaldehyde was added and the reaction mass was heated to reflux. Water formed in the reaction was continuously removed. After 4 hours the reaction mass was cooled to 30° C. and 133 ml. of 6.6N hydrochloric acid solution in dimethyl formamide was added. The reaction mass was heated to 70° C. for 4 hours. The reaction cooled to 15° C. and filtered under suction and washed with dichloroethane. The solid obtained was dried in oven at 50° C. 124 gm (90%) of 4,5,6,7-tetrahydrothieno(3,2-c)pyridine hydrochloride are obtained.

Provenance & Evidence