Reactions of sulfides with S-330, a potential decontaminant of sulfur mustard in formulations

Because the vesicant sulfur mustard (HD) remains a major chemical threat from either domestic terrorists or countries in conflict, topical preparations are being evaluated as protectants from HD exposure. The objective of this study was to evaluate the effectiveness of chloroamide S-330 as a potential reactive component in topical formulations. Therefore, the rate, mechanism and by-products of the oxidation reactions of sulfides by S-330 in solvent media or specific formulation vehicles were investigated. Using NMR, LC, LC-MS and GC-MS, the reactions of S-330 with HD, dibutyl sulfide (DBS) and methyl phenyl sulfide (MPS) were studied in acetonitrile, chloroform and perfluoropolyether (PFPE) oil. The oxidation of the three sulfides with S-330 was very rapid and completed in <4 min in acetonitrile-water or PFPE oil, but the rates of reaction in chloroform were significantly slower. In a large excess of S-330, the major products resulted from chlorination of the side chains. At a high HD/S-330 ratio, the major product was HD sulfoxide. Under both conditions, only a trace of HD sulfone, also a blistering agent, was observed. Reactions with DBS and MPS primarily gave sulfoxides and sulfones, with less side-chain chlorination. The chloroamide S-330 appeared to be a rapid and effective decontaminant of HD in either polar media or in a PFPE oil. The two alkyl and aryl sulfides are suitable simulants of HD for the initial screening and evaluation of S-330 or other similar oxidizing agents.