Synthesis of 2-Arylbenzothiazoles by DDQ-Promoted Cyclization of Thioformanilides; A Solution-Phase Strategy for Library Synthesis
作者:D. Bose、Mohd. Idrees、Bingi Srikanth
DOI:10.1055/s-2007-965929
日期:2007.3
Several substituted benzothiazoles were synthesized by the intramolecular cyclization of thioformanilides using 2,6-dichloro-3,5-dicyano-1,4-benzoquinone (DDQ) in dichloromethane at ambient temperature in high yields. The resulting 2-arylbenzothiazoles were separated from the reduced DDQ byproduct 4,5-dichloro-3,6-dihydroxyphthalonitrile by treatment of the reaction mixture with a strongly basic ion-exchange resin. This protocol offers a high degree of flexibility with regard to the functional groups that can be placed on the benzothiazole ring or 2-aryl moiety, which in turn generates scaffolds for parallel synthesis.
The graphene oxide-catalyzed coupling and cyclization reactions of primary amines with elemental sulfur was developed to afford various optically property benzothiazoles. This coupling and cyclization strategies proceeded under the oxidant system graphene oxide/O2 and constructed carbon-heteroatom (N, S) bonds with amines and elemental sulfur. Due to benzothiazoles as common chromophores, these products
A convenient access to substituted benzothiazole scaffolds via intramolecular cyclization of thioformanilides
作者:D. Subhas Bose、Mohd. Idrees
DOI:10.1016/j.tetlet.2006.11.105
日期:2007.1
A new and practical method has been developed for the synthesis of substituted benzothiazoles via the intramolecular cyclization of thioformanilides using DDQ in CH2Cl2 at ambient temperature. The reaction proceeds in high yields via the thiyl radical to give novel oxybis-benzothiazole, and offers a high degree of flexibility with regard to the functional groups that can be placed on the benzothiazole
multicomponent tandem cyclization and aromatization approach is introduced for the synthesis of naphthothiazoles and benzothiazoles from α-tetralones and cyclohexenones, respectively. Styrene derivatives were employed to generate one-carbon synthons through C=C bond cleavage, while an ammonium salt served as the nitrogen source and elementalsulfur served both as the sulfur source and oxidant.