Synthesis and antioxidant studies of novel N-substituted benzyl/phenyl-2-(3,4-dimethyl-5,5-dioxidopyrazolo[4,3-c][1,2]benzothiazin-2(4H)-yl)acetamides

Two new series of twenty-two N-substituted benzyl/phenyl-2-(3,4-dimethyl-5,5-dioxidopyrazolo[4,3-c][1,2]benzothiazin-2(4H)-yl)acetamides were synthesized by synergism of the dihydropyrazolo[4,3-c][1,2]benzothiazine 5,5-dioxide moiety with side chain of carboxamides. The routes of formation for these products have been discussed. All the compounds were characterized by NMR, mass and elemental analysis. Structures of compounds 6d and 6l have been elucidated by X-ray crystallography. The synthesized compounds were screened to the preliminary evaluation for their anti-oxidant activities and most of the compounds were found to possess moderate to significant radical scavenging activity. Furthermore, these compounds could be useful as a template for future development through modification or derivatization to design more potent biologically active compounds. [Two series of novel carboxamides based upon pyrazolobenzothiazine ring system have been synthesized and evaluated for antioxidant activity. Many compounds were found to be good scavengers of superoxide anion radical. Moreover, the compounds may also possess the bioactivities of parent ring system and thus, are useful as template for further development of new bioactive molecules.].