Lead Optimization of Dimethyl(2-phenoxyethyl)sulfonium p-Toluenesulfonate for the Development of an Anti-allergic Agent

Derivatives of dimethy-2-phenoxyethylsulfonium p-toluenesulfonate (1) were evaluated for anti-allergic activity to develop the drug for treatment of type I allergic diseases as a lead optimization step. The IgE-induced passive cutaneous anaphylaxis (PCA) of rats was inhibited upon oral administration by 3-ethoxy, 3-phenoxy, and 2, 3-diethoxypropoxyphenoxy derivatives. The lead compound 2-[4-(3-ethoxy-2-hydroxypropoxy)phenoxy]ethyldimethyl- sulfonium p-toluenesulfonate (11) was selected as a candidate for preclinical study by considering its toxicity and cholinergic activity.