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Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and β-ketoamides

Two regiodivergent approaches to intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and amides have been developed, controlled by the reagents employed. With the Brønsted base KOt-Bu and CBrCl(3) as radical initiator, benzo[d]imidazo[2,1-b]thiazoles are synthesized via attack at t...

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Detalles Bibliográficos
Autores principales: Roslan, Irwan Iskandar, Ng, Kian-Hong, Chuah, Gaik-Khuan, Jaenicke, Stephan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Beilstein-Institut 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5753174/
https://www.ncbi.nlm.nih.gov/pubmed/29564009
http://dx.doi.org/10.3762/bjoc.13.270
Descripción
Sumario:Two regiodivergent approaches to intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and amides have been developed, controlled by the reagents employed. With the Brønsted base KOt-Bu and CBrCl(3) as radical initiator, benzo[d]imidazo[2,1-b]thiazoles are synthesized via attack at the α-carbon and keto carbon of the β-ketoester moiety. In contrast, switching to the Lewis acid catalyst, In(OTf)(3), results in the regioselective nucleophilic attack at both carbonyl groups forming benzo[4,5]thiazolo[3,2-a]pyrimidin-4-ones instead.