A facile and convenient method for synthesis of alkyl thiocyanates under homogeneous phase transfer catalyst conditions Ali Reza Kiasat * , Rashid Badri, Soheil Sayyahi Chemistry Department, College of Science, Shahid Chamran University, Ahvaz 61357-4-3169, Iran Received 15 May 2008 Abstract A simple and environmentally friendly method is described for the efficient conversion of alkyl halide to alkyl thiocyanate using tetrabutylammonium bromide (TBAB) as a phase transfer catalyst. The reactions occur in water and furnish the corresponding alkyl thiocyanate in high yields. No evidence for the formation of isothiocyanates as by-product of the reaction was observed and the products were obtained in pure form without further purification. # 2008 Ali Reza Kiasat. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. Keywords: Alkyl thiocyanate; Alkyl halide; Tetrabutylammonium bromide; Phase transfer catalyst; Synthesis of alkyl thiocyanates It is well known that the alkyl thiocyanate [1] plays an important role as an intermediate for the preparation of sulfur-containing organic compounds [2]. They have found a wide variety of applications as insecticides, biocidal, antiasthmatic and starting materials for the preparation of heterocycles. Thiocyanates are also considered to be an important class of compounds found in some anticancer natural products formed by deglycosylation of glucosinolates derived from cruciferous vegetables [3]. Moreover, a-thiocyanatocarbonyl compounds are intermediates for a preferred synthetic route to several types of thiazoles [4]. Thiocyanation is generally carried out via nucleophilic substitution using thiocyanate anions. A number of methods are available for the preparation of alkyl thiocyanates, such as, displacement of leaving groups with thiocyanate ions [5–7]. Thiocyanates can also be obtained from alcohols [8], silyl ethers [9] or amines [10]. However, this displacement frequently requires rather severe reaction conditions because of the low nucleophilicity of the NCS  ion. Hence many drawbacks and low yields have been observed for these thiocyanation methodologies [2,11]. In addition, the thiocyanate group is poorly stable when heated or under acidic conditions. Chromatography on silica gel or prolonged heating over 50 8C can cause intramolecular rearrangement to the thermodynamically favored isothiocyanate isomers [12]. Consequently, the development of new methods that are more efficient and lead to convenient procedures and better yields is desirable. Phase transfer catalysts (PTCs) are powerful reagents in chemical transformations [13,14], the characteristics of which include mild reaction conditions, safety, operational simplicity and selectivity. PTCs are often used in nucleophilic displacement reactions to facilitate reactions between organic reactants and ionic inorganic salts [15]. www.elsevier.com/locate/cclet Available online at www.sciencedirect.com Chinese Chemical Letters 19 (2008) 1301–1304 * Corresponding author. E-mail address: akiasat@scu.ac.ir (A.R. Kiasat). 1001-8417/$ – see front matter # 2008 Ali Reza Kiasat. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. doi:10.1016/j.cclet.2008.07.019