Synthesis and Biological Activities of Camphor Hydrazone and Imine Derivatives

Abstract

Both sonochemical and classical methodologies have been employed to convert camphor, 1,7,7-trimethylbicyclo[2.2.1]heptan-2-one, C₉H₁₆C=O, into a number of derivatives including hydrazones, C₉H₁₆C=N-NHAr <b>3</b>, imines, C₉H₁₆C=N-R <b>7</b>, and the key intermediate nitroimine, C₉H₁₆C=N-NO₂ <b>6</b>. Reactions of nitroamine <b>6</b> with nucleophiles by classical methods provided the desired compounds in a range of yields. In evaluations of activity against <i>Mycobacterium tuberculosis</i>, compound <b>7j</b> exhibited the best activity (minimal inhibitory concentration (MIC) = 3.12 µg/mL), comparable to that of the antitubercular drug ethambutol. The other derivatives displayed modest antimycobacterial activities at 25-50 µg/mL. In in vitro tests against cancer cell lines, none of the synthesized camphor compounds exhibited cytotoxic activities.