Urea → methyl 4-(5-chloro-1,3-dihydro-2-oxo-2H-benzimidazol-1-yl)-3-methyl-1-piperidinecarboxylate

Participants

Reaction Steps

A mixture of 30 parts of methyl 4-(2-amino-4-chlorophenylamino)-3-methyl-1-piperidinecarboxylate and 10 parts of urea is stirred and heated at 160°-180° C (oil-bath) for 3h. 30. The reaction mixture is cooled and the product is extracted with methylbenzene. The extract is washed successively with water, with a diluted hydrochloric acid solution and again with water, dried, filtered and evaporated. The oily residue is crystallized from a warm mixture of 2,2'-oxybispropane and a small amount of 2-propanol. After cooling, the product is filtered off and dried, yielding methyl 4-(5-chloro-1,3-dihydro-2-oxo-2H-benzimidazol-1-yl)-3-methyl-1-piperidinecarboxylate; mp. 196.2° C.

Provenance & Evidence