I2/CH3ONa-Promoted Ring-Opening Alkylation of Benzothiazoles with Dialkyl Carbonates

Abstract Dialkyl carbonates were used as the green alkylating reagents in the I2-promoted ring-opening alkylation of benzothiazoles. A variety of benzo[d]thiazole derivatives underwent the alkylation smoothly to provide the diverse N-alkyl-N-(o-alkylthio)phenylformamides in moderate to excellent yields. The synthetic utility of this protocol was verified by gram-scale reaction and further derivatization of the products. The mechanism of the involvement of two molecules of dialkyl carbonates in the formation of sulfur-alkyl and nitrogen-alkyl groups, respectively, was also demonstrated.