Copper(II)- and gold(III)-mediated cyclization of a thiourea to a substituted 2-aminobenzothiazole.

Autor: Schroeder ZW; Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave. W., Waterloo, Ontario, N2L 3C5, Canada., Hiscock LK; Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave. W., Waterloo, Ontario, N2L 3C5, Canada., Dawe LN; Department of Chemistry and Biochemistry, Wilfrid Laurier University, 75 University Ave. W., Waterloo, Ontario, N2L 3C5, Canada.
Jazyk: angličtina
Zdroj: Acta crystallographica. Section C, Structural chemistry [Acta Crystallogr C Struct Chem] 2017 Nov 01; Vol. 73 (Pt 11), pp. 905-910. Date of Electronic Publication: 2017 Oct 13.
DOI: 10.1107/S205322961701381X
Abstrakt: Benzothiazole derivatives are a class of privileged molecules due to their biological activity and pharmaceutical applications. One route to these molecules is via intramolecular cyclization of thioureas to form substituted 2-aminobenzothiazoles, but this often requires harsh conditions or employs expensive metal catalysts. Herein, the copper(II)- and gold(III)-mediated cyclizations of thioureas to substituted 2-aminobenzothiazoles are reported. The single-crystal X-ray structures of the thiourea N-(3-methoxyphenyl)-N'-(pyridin-2-yl)thiourea, C 13 H 13 N 3 OS, and the intermediate metal complexes aquabis[5-methoxy-N-(pyridin-2-yl-κN)-1,3-benzothiazol-2-amine-κN 3 ]copper(II) dinitrate, [Cu(C 13 H 11 N 3 OS) 2 (H 2 O)](NO 3 ) 2 , and bis{2-[(5-methoxy-1,3-benzothiazol-2-yl)amino]pyridin-1-ium} dichloridogold(I) chloride monohydrate, (C 13 H 12 N 3 OS) 2 [AuCl 2 ]Cl·H 2 O, are reported. The copper complex exhibits a distorted trigonal-bipyramidal geometry, with direct metal-to-benzothiazole-ligand coordination, while the gold complex is a salt containing the protonated uncoordinated benzothiazole, and offers evidence that metal reduction (in this case, Au III to Au I ) is required for the cyclization to proceed. As such, this study provides further mechanistic insight into the role of the metal cations in these transformations.
Databáze: MEDLINE
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