Journal of Physical Chemistry and Electrochemistry Journal homepage: http://journals.miau.ac.ir/jpe Journal of Physical Chemistry and Electrochemistry Vol.2 No. 3(2014) 119-123 Islamic Azad University Marvdasht Branch * Correspondig Author E-mail address: polychemfar@gmail.com Poly(N- bromosuccinimide) (PNBS) as a mild, effcient, non-acidic, polymeric and hetero- geneous catalyst applied for easy conversion of epoxides into thiiranes by treatment with KSCN or (NH 2 ) 2 CS at room temperature Farzaneh Ebrahimzadeh * Department of Chemistry, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran, Abstract Poly (N-bromosuccinimide) (PNBS) as a mild, effcient, non-acidic, polymeric and heterogeneous catalyst was applied for simple conversion of epoxides into thiiranes by treatment with KSCN or (NH 2 ) 2 CS at room temperature. Aliphatic and aromatic epoxides converted into their corresponding thiiranes under mild conditions. All reactions proceeded in short reaction times and afforded the corresponding products in good to excellent yields. The catalyst could be recycled and reused for several times without any deterioration in its activity. Advantages such as easy preparation of the catalyst, simple work up, excellent yields of the products and recyclability of the catalyst makes this method more useful compared to the known methodologies. Keywords: polymer, catalyst, thiirane, epoxide, heterogeneous catalyst 1.Introduction Thiiranes have found applications in pharmaceutical, pesticide and polymer industries. Various methods have been developed for the preparation of these compounds. [1] The most general one is based on the conversion of oxiranes to thiiranes by an oxygen–sulfur exchange reaction [2]. For this purpose, several sulfur-introducing agents, including inorganic thiocyanates [3], 3-methylbenzothiozole-2-thione [4], dimethylthioformamide [5], thiourea [6], and phosphine sulfde [7] have been utilized. Besides a sulfurated reagent, a protic acid such as TFA [4,5,7], or a Lewis acid such as RuCl 3 [8], BiCl 3 [9], TiO(CF 3 COO) 2 [8], TiCl 3 (CF 3 SO 3 ) [10], and InBr 3 [11] is employed. Conversion of epoxides to thiiranes with NH 4 SCN and thiourea in the presence of a suitable catalyst is important in organic chemistry [12]. However, some of these methods suffer from drawbacks such as low yield, rapid increase of pH during the reaction (which leads to ready polymerization of thiirans and lowering of the yield), high acidity of the catalyst or reagent, the non-catalytic nature of the reagents, long reaction times, inconvenient handling and limitation of the substrates