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Abstract
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Efficient, odorless and scalable synthetic protocols have been introduced for the preparation of symmetric
alkyl disulfides by treatment of the corresponding organic halides with thiourea and NaHCO3 in
the presence of commercially available Europhtal catalyst (8020) in both H2O and poly ethylene glycol
(PEG-200) media at 80e90 C. Structurally diverse primary, secondary, allylic and benzylic halides were
examined successfully whereas, the result with tert-butyl bromide was not satisfactory. Also, another
procedure has been introduced for achieving symmetric aryl disulfides in high yields by reacting aryl
halides, thiourea and NaHCO3 in PEG-200 at 115e120 C using CuI along with Europhtal catalysts. The
results showed that the aerobic oxidation of in situ generated thiols proceeded efficiently in the presence
of Europhtal catalyst giving the symmetric disulfide without contamination by symmetric sulfide sideproduct.
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