Synthesis of 2-aminobenzothiazole via FeCl3-catalyzed tandem reaction of 2-iodoaniline with isothiocyanate in water

Abstract

An FeCl 3 -catalyzed tandem reaction of 2-iodoaniline with isothiocyanate in water is described, which provides an environmentally benign, efficient, and practical route for the generation of 2-aminobenzothiazole. This present tandem process shows broad substrate scope in the presence of octadecyltrimethylammonium chloride as a phase-transfer catalyst. In addition, the reaction media can be recovered and recycled without loss of efficiency.

Iron Catalysis in Organic Synthesis

“…616 DABCO (1,4-diazabicyclo-[2.2.2]octane) was added as base, and the reaction was performed in water at 80°C in the presence of octadecyltrimethylammonium chloride (PTC-4).…”

A practical synthesis of 2-aminobenzothiazoles via the tandem reactions of 2-haloanilines with isothiocyanates catalyzed by immobilization of copper in MCM-41

“…Recently, the transition-metal-catalyzed tandem reactions of 2-halobenzenamines and isothiocyanates for the synthesis of 2-aminobenzothiazoles have received considerable attention because of their efficiency and low costs. For example, Wu and coworkers described a copper-catalyzed tandem reaction between 2-halobenzenamines and isothiocyanates using the CuI (10 mol %)/1,10-phenanthroline (20 mol%) catalytic system to prepare 2-aminobenzothiazoles [10]; Li and Ding's groups reported ironcatalyzed tandem reactions of 2-halobenzenamines and isothiocyanates leading to 2-aminobenzothiazoles [13,14]. Meanwhile, the ligand-free copper-catalyzed tandem reactions of 2-halobenzenamines and isothiocyanates were also reported [15,16].…”

Water-Mediated Synthesis of Benzazole and Thiourea Motifs by Reacting Naturally Occurring Isothiocyanate with Amines

“…[12] Ding et al synthesized 2-aminobenzothiazole derivatives using copper(I)-catalyzed tendem addition-cyclization reaction in toulene [13] and FeCl 3 in water with a phase-transfer catalyst, base (DABCO), and ligand. [14] Li et al synthesized the same core using FeF 3 or CuBr catalyst. [15] Copper-based catalysts have also been applied for similar transformations in water.…”