Triethylamine → N-Methyl-N'-(4,5,6,7-tetrahydro-1-benzothiophen-4-yl)urea

Participants

Reaction Steps

A mixture of 1.89 grams (0.01 mole) of 4,5,6,7-tetrahydrobenzo[b]thiophen-4-amine hydrochloride in 20 ml. of dry benzene is stirred while 1.05 grams (0.01 mole) of triethylamine and 01.7 ml. (excess) of methyl isocyanate are added successively. Addition of the latter gives rise to an exotherm, and the mixture becomes very pasty. The mixture is kept at 45° C. for 1 hour, and after cooling to room temperature, the solid is collected, washed thoroughly with benzene and then with water. On drying, this gives 1.7 grams (81%) of product, melting point 183° C. to 186° C. Recrystallization from acetone gives 1.23 grams, melting point 187.5° C. to 189° C.

Provenance & Evidence