1-Piperazinecarboxylic acid, ethyl ester → Ethyl 4-(1,2-benzisothiazol-3-yl)-1-piperazinecarboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of 32 parts of ethyl 1-piperazinecarboxylate, 17 parts of 3-chloro-1,2-benzisothiazole and 45 parts of N,N-dimethylacetamide was stirred for 0.5 hours at 150° C. After cooling to 50° C., the reaction mixture was poured into ice water. The aqueous layer was decanted and the oily layer was stirred in water. The product from the oil layer was extracted with trichloromethane. The extract was dried, filtered and evaporated. The residue was purified by column chromatography over silica gel using a mixture of trichloromethane and methanol (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated, yielding 13 parts (44%) of ethyl 4-(1,2-benzisothiazol-3-yl)-1-piperazinecarboxylate as a residue (int. 3).

Provenance & Evidence