Synthesis Of Benzothiazine And Isoindolinone Catalyzed By Transition Metals

Benzothiazine and isophthalone homologues are important heterocyclics and widely exist in a variety of natural products and bioactive molecules.They are the most crucial heterocyclic frameworks in natural alkaloids which possess many biological activities,as well as the crucial structure motifs of pharmacieal molecules.This paper focuses on the synthesis of benzothiazine and isoindolinone compounds,and consists of the four parts:(1)The recent research on benzothiazine and isoindolinone derivatives has been reviewed.(2)Copper-catalyzed three-component(isothiocyanate,terminal alkyne and ammonia)one-pot tandem cyclization was studied for synthesis of 1,4-benzothiazines.The elimination of aryl thioureas generated in situ leaded to arylcyanamide,which triggered the following double C-S bond formation and intramolecular hydroamination to give 1,4-benzothiazines in moderate to good yields.(3)Pd-catalyzed C-H activation of N-benzyl-N-methylnitrous amide was investigated to furnish isoindolinone derivatives in moderate to good yields using nitroso as a novel traceless directing group.The reaction proceeded via the installation of directing group,carbonylation and elimination.(4)Copper-catalyzed coupling reaction of benzothiazole and diazo compounds was developed.The present process provided an approach for the construction of C-C and C-N bonds to afford benzothiazole derivatives in moderate yields.