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

ABSTRACT: Two regiodivergent approaches to intermolecular cyclization of 2-aminobenzothiazoles with ?-ketoesters and amides have been developed, controlled by the reagents employed. With the Brønsted base KOt-Bu and CBrCl3 as radical initiator, benzo[d]imidazo[2,1-b]thiazoles are synthesized via attack at the ?-carbon and keto carbon of the ?-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.

SUBMITTER: Roslan II

PROVIDER: S-EPMC5753174 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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

Roslan Irwan Iskandar II Ng Kian-Hong KH Chuah Gaik-Khuan GK Jaenicke Stephan S

Beilstein journal of organic chemistry 20171218

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 CBrCl3 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 ...[more]

PMID: 29564009

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