Iron‐Catalyzed Tandem Reactions of 2‐Halobenzenamines with Isothiocyanates Leading to 2‐Aminobenzothiazoles

Abstract

A highly practical method for the synthesis of 2-aminobenzothiazoles has been developed through an iron-catalyzed tandem reaction. The present tandem process allows the assembly of a wide range of 2-aminobenzothiazoles by the reactions of 2-halobenzenamines with isothiocyanates.

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

“…1 H NMR spectra were recorded on a Bruker Avance (400 MHz) spectrometer with TMS as an internal standard in CDCl 3 as solvent. 13 C NMR spectra were recorded on a Bruker Avance (100 MHz) spectrometer in CDCl 3 as solvent. Melting points are uncorrected.…”

“…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].…”

Development of Divergent Synthetic Methods of Pyrimidobenzothiazine and Related Tricyclic Heterocycles

“…Bao and co-workers have reported the formation of 2-amino-benzothiazoles 5 by CuI-catalyzed coupling of 2-haloanilines 4 and isothiocyanates (eq 2) [44] Li and co-workers have revealed that thses 2-aminobenzothiazole formation reactions were assisted by an Fe(III) catalyst [45]. These reactions proceed via nucleophilic addition of aniline to isothiocyanate followed by transition-metal-catalyzed intramolecular S-arylation.…”

“…With these findings [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53], the author investigated the transition-metal (Pd, Cu, Fe, etc.) catalyzed coupling of haloarenes 6aa and heterocumulenes.…”

Transition-metal-free synthesis of imidazobenzothiazines via domino C-S/C-N bond formation

“…In the synthesis of these compounds, tandem C-S/C-N formation shows obvious advances over other methods due to their facile one-pot procedure [34][35][36][37]. In addition, recent advances in tandem reactions with C-X (X=N, S, O) coupling reactions show their great importance in both methodology development [37][38][39][40][41][42] and natural product synthesis [43]. However, these tandem reactions are always carried out in presence of transition metals.…”