Koyanagi Arisu, Murata Yuki, Hayakawa Shiori, Matsumura Mio, Yasuike Shuji
School of Pharmaceutical Sciences, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan.
Beilstein J Org Chem. 2022 Oct 18;18:1479-1487. doi: 10.3762/bjoc.18.155. eCollection 2022.
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.
2-取代苯并唑衍生物新型高效合成方法的开发备受关注，因为它们是生物活性物质。本文描述了一种合成2-芳基和2-烷基取代苯并唑的简便方法。在二氯乙烷中，2-氨基酚与硫代酰胺在60℃下，以二氯三苯基铋作为促进剂进行反应，在温和的反应条件下以中等至优异的产率得到了各种2-芳基和2-烷基苯并恶唑。该方法也可应用于苯并咪唑和苯并噻唑的合成。本研究首次使用二氯三苯基铋通过脱硫和氯化从硫代酰胺制备苯甲酰氯，以及其在合成2-取代苯并唑中的应用。
