An “on-water” exploration of CuO nanoparticle catalysed synthesis of 2-aminobenzothiazoles
- 13 June 2012
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Green Chemistry
- Vol. 14 (9), 2491-2498
- https://doi.org/10.1039/c2gc35575b
Abstract
An “on-water” one-pot process has been engineered for the preparation of 2-aminobenzothiazole from ortho-halo (–F, –Cl, –Br and –I) substituted unsymmetrical thioureas. For ortho –I and –Br substrates the reactions afford 2-aminobenzothiazoles under metal free condition promoted by base. However, the relatively inert ortho –Cl and –F substrates undergo intramolecular arylthiolation only in the presence of CuO nanoparticles yielding 2-aminobenzothiazoles. This methodology provides easy access to aminobenzothiazoles utilising even the ortho –Cl and –F substrates. The catalyst is recyclable several times without loss of substantial activity. Other remarkable features include the wide range of functional group tolerance, absence of chromatographic purification (for ortho –I and –Br substrates) and providing moderate to excellent yield of the products under mild conditions, thus rendering the methodology as a highly eco-friendly alternative to the existing methods.Keywords
This publication has 79 references indexed in Scilit:
- Regioselective Intramolecular Arylthiolations by Ligand Free Cu and Pd Catalyzed ReactionACS Catalysis, 2012
- An economically and environmentally sustainable synthesis of 2-aminobenzothiazoles and 2-aminobenzoxazoles promoted by waterGreen Chemistry, 2011
- l-Histidine and l-arginine promote Knoevenagel reaction in waterAmino Acids, 2010
- Synthesis of 2-aminobenzothiazole via FeCl3-catalyzed tandem reaction of 2-iodoaniline with isothiocyanate in waterGreen Chemistry, 2010
- Palladium-Catalyzed Synthesis of 2-Substituted Benzothiazoles via a C−H Functionalization/Intramolecular C−S Bond Formation ProcessOrganic Letters, 2008
- Highly Reactive, General and Long-Lived Catalysts for Palladium-Catalyzed Amination of Heteroaryl and Aryl Chlorides, Bromides, and Iodides: Scope and Structure–Activity RelationshipsJournal of the American Chemical Society, 2008
- N‐Arylation of Heterocycles with Activated Chloro‐ and Fluoroarenes using Nanocrystalline Copper(II) OxideAdvanced Synthesis & Catalysis, 2007
- Microwave-Accelerated Solvent- and Catalyst-Free Synthesis of 4-Aminoaryl/alkyl-7-chloroquinolines and 2-Aminoaryl/alkylbenzothiazolesAustralian Journal of Chemistry, 2007
- Anticonvulsant and neurotoxicity evaluation of some 6-substituted benzothiazolyl-2-thiosemicarbazonesIl Farmaco, 2005
- Comparative mobility of halogens in reactions of dihalobenzenes with potassium amide in ammoniaThe Journal of Organic Chemistry, 1971