Suplatast tosilate

Suplatast tosilate (INN) is an inhibitor of cytokine T helper cells. Overstimulation of these Th2 cells can lead to an allergic reaction, so the drug is used as an antihistamine. It has also been used in the treatment of Kimura's disease.

Synthesis

 * Suplatast synthesis.svg

Acylation of 1-(4-aminophenoxy)-3-ethoxypropan-2-ol (1) with 3-methylthiopropionyl chloride (2) gives the amide (3). Methylation of the thioether using methyl tosylate (4) yields suplatast as its toluenesulfonic acid salt.