It is the same structure as for procainamide, differing only by the placement of a mesyl sulfonamide moiety to the anilino nitrogen.

The reaction between Benzocaine (Ethyl 4-Aminobenzoate) [94-09-7] (1) and mesyl chloride [124-63-0] gives the sulfonamide, Ethyl 4-(Methylsulfonamido)benzoate [7151-77-1].

Base saponification followed by the removal of the water from the reaction mixture gives 4-[(Methylsulfonyl)amino]benzoic acid sodium salt (2).

Amide formation with N,N-Diethylethylenediamine [100-36-7] (3) then concludes the synthesis of Sematilide (4).

This article about an organic compound is a stub.