Regioselective Thiocyanation of Aromatic and Heteroaromatic Compounds Using [2-(Sulfooxy)ethyl]sulfamic Acid as an Efficient, Recyclable Organocatalyst and Novel Difunctional Brønsted Acid

Abstract

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 2aminoethanol 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.

Sulfamic Acid as Versatile Green Catalyst Used For Synthetic Organic Chemistry: A Comprehensive Update

“…In an effort to address the requirements of green chemistry and cost effectiveness, synthesis of silica-supported [2-(Sulfooxy)ethyl] sulfamic acid (SESA) was described (Scheme 69) and used as a catalyst for the thiocyanation of aromatic and heteroaromatic compounds. [130] The catalyst was found efficient for the thiocyanation of heterocycles, substituted anilines (electronrich and electron-deficient), and N,N-disubstituted aromatic The production of a heterogeneous acidic catalyst consisting of N-propyl sulfamic acid-functionalize polymeric network based on calix[4]resorcinarene was described by Mouradzadegun and Mostafavi [135] (Figure 6). The catalyst was used for the efficient synthesis of 1,8-dioxo-octahydroxanthenes by the condensation reaction of dimedone with various aryl aldehydes under thermal solvent-free conditions (Scheme 77).…”

“…A number of methods were suggested for the synthesis of aryl thiocyanate groups, [129] but most reported methods have specific drawbacks such as using strong acidic or oxidizing agents, high temperature requirements, low yield, long reaction time, and the employment of large amounts of toxic or expensive catalysts. In an effort to address the requirements of green chemistry and cost effectiveness, synthesis of silica‐supported [2‐(Sulfooxy)ethyl]sulfamic acid (SESA) was described (Scheme 69) and used as a catalyst for the thiocyanation of aromatic and heteroaromatic compounds [130] . The catalyst was found efficient for the thiocyanation of heterocycles, substituted anilines (electron‐rich and electron‐deficient), and N,N ‐disubstituted aromatic amines using hydrogen peroxide in the H 2 O/EtOH solvent at room temperature (Scheme 70).…”