%0 Journal Article
%T Regioselective Thiocyanation of Aromatic and Heteroaromatic Compounds Using [2-(Sulfooxy)ethyl]sulfamic Acid as an Efficient, Recyclable Organocatalyst and Novel Difunctional Br£¿nsted Acid
%A Sami Sajjadifar
%A Saaid Karimian
%A Hadi Noorizadeh
%A Hojat Veisi
%J Journal of Catalysts
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/723903
%X A green and simple procedure for the thiocyanation of aromatic and heteroaromatic compounds is described. [2-(Sulfooxy)ethyl]sulfamic acid (SESA) (supported on silica) is easily produced by addition of chlorosulfonic acid to 2-aminoethanol and this catalyst is applied as an efficient, reusable, and heterogeneous catalyst for the thiocyanation of heterocycles, substituted anilines (electron-rich and electron-deficient), and N,N-disubstituted aromatic amines using hydrogen peroxide in the water£¿:£¿ethanol as a solvent at room temperature. The catalyst can be easily recovered and reused for five reaction cycles without considerable loss of activity. 1. Introduction The importance of minimizing the impact that chemical processing has on the environment is growing, with an increased appreciation of the need to reduce pollution and depletion of our finite environmental resources. Optimal use of material and energy and an efficient waste management can be recognized as important factors for environmental protection. To realize this goal, in recent years, significant articles have appeared reporting efficient solvent-free reactions by grinding [1¨C3]. This technique has many advantages such as reduced pollution, low cost, process simplicity, and easier workup. In addition, from the green and environmental acceptability, recently more attention has been paid to the application of inorganic acidic salts in organic synthesis [4, 5]. Solid acids have many advantages such as simplicity in handling, decreased reactor and plant corrosion problems, and more environmentally safe disposal in different chemical processes. Also, wastes and byproducts can be minimized or avoided by using solid acids in developing cleaner synthesis routes. The electrophilic thiocyanation of aromatics and heteroaromatics is an important carbon-heteroatom bond-forming reaction in organic synthesis. Organocatalysis has emerged during the last decade as one of the major issues in the development of catalytic chemical technology [6]. As for conventional catalysis with transition metal complexes, by using organic catalysts large quantities of products are expected to be prepared using a minimal amount of small organic molecules [7, 8]. The recent organocatalytic protocols are particularly attractive because of the mildness of the reaction conditions, operational simplicity, the potential for the development of large-scale production, and the ready availability and low toxicity of the organocatalysts [9, 10]. Organocatalyzed reactions using water as a solvent have attracted a great deal of attention
%U http://www.hindawi.com/journals/jcat/2013/723903/