One-pot synthesis of 2-arylated and 2-alkylated benzoxazoles and benzimidazoles based on triphenylbismuth dichloride-promoted desulfurization of thioamides

Autor: Arisu Koyanagi, Yuki Murata, Shiori Hayakawa, Mio Matsumura, Shuji Yasuike
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Beilstein Journal of Organic Chemistry, Vol 18, Iss 1, Pp 1479-1487 (2022)
Druh dokumentu: article
ISSN: 1860-5397
DOI: 10.3762/bjoc.18.155
Popis: The development of novel and efficient synthesis methods for 2-substituted benzazole derivatives is of interest as they are biologically active substances. Herein, a simple method for the synthesis of 2-aryl- and 2-alkyl-substituted benzazoles is described. The reaction of 2-aminophenols with thioamides at 60 °C in the presence of triphenylbismuth dichloride in 1,2-dichloroethane as a promoter afforded various 2-aryl- and 2-alkylbenzoxazoles in moderate to excellent yields under mild reaction conditions. This method could also be applied to the synthesis of benzimidazoles and benzothiazoles. This study presents the first use of triphenylbismuth dichloride to produce benzimidoyl chloride from thioamides by desulfurization and chlorination, as well as its application to the synthesis of 2-substituted benzazoles.
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