Base-promoted expedient access to spiroisatins: Synthesis and antitubercular evaluation of 1 h -1,2,3-triazole-tethered spiroisatin-ferrocene and isatin-ferrocene conjugates

Abstract

The use of sodium hydride provides a convenient access to the synthesis of C-5-functionalized spiroisatins with the absence of the typical drawbacks associated with conventional protocols. The synthesized precursors, viz. N-alkylazido spiroisatins and their unprotected counterparts, were explored in Cu-mediated azide-alkyne cycloaddition reactions to probe the antitubercular structure-activity relationships (SAR) within the isatin-ferrocene-triazole conjugate family. The antitubercular evaluation studies of the synthesized conjugates revealed an improvement in the minimal inhibitory concentration (MIC) with the introduction of ferrocene nucleus, as evidenced by spiroisatin-ferrocene and isatin-ferrocene hybrids. © 2013 American Chemical Society.