Synthesis of Novel Fluoro Phenyl Triazoles Via Click Chemistry with or without Microwave Irradiation and their Evaluation as Anti-proliferative Agents in SiHa Cells

AIMS

Perform the synthesis of novel fluoro phenyl triazoles via click chemistry with or without microwave irradiation and their evaluation as anti-proliferative agents in SiHa cells.

BACKGROUND

Triazoles are heterocyclic compounds containing a five-member ring with two carbon and three nitrogen atoms. They are of great importance since many of them have shown to have biological activity as antifungal, antiviral, antibacterial, anti-HIV, anti-tuberculosis, vasodilator, and anticancer agents.

OBJECTIVES

Synthesize novel fluoro phenyl triazoles via click chemistry and evaluate their antiproliferative activity.

METHODS

First, several fluorophenyl azides were prepared. Reacting these aryl azides with phenylacetylene in the presence of Cu(I) catalyst, the corresponding fluoro phenyl triazoles were obtained by two methodologies, stirring at room temperature and under microwave irradiation at 40ºC. In addition, their antiproliferative activity was evaluated in cervical cancer SiHa cells.

RESULTS

Fluoro phenyl triazoles were obtained within minutes by means of microwave irradiation. The compound 3f, containing two fluorine atoms next to the carbon connected to the triazole ring, was the most potent among the fluoro phenyl triazoles tested in this study. Interestingly, the addition of a fluorine atom to the phenyl triazole structure in a specific site increases its antiproliferative effect as compared to parent phenyl triazole 3a without a fluorine atom.

CONCLUSION

Several fluoro phenyl triazoles were obtained by reacting fluoro phenyl azides with phenylacetylene in the presence of copper sulphate, sodium ascorbate and phenanthroline. Preparation of these triazoles with MW irradiation represents a better methodology since they are obtained within minutes and higher yields of cleaner compounds are obtained. In terms of biological studies, the proximity between fluorine atom and triazole ring increases its biological activity.

Recent Advances in Microwave-Assisted Copper-Catalyzed Cross-Coupling Reactions

Cross-coupling reactions furnishing carbon–carbon (C–C) and carbon–heteroatom (C–X) bond is one of the most challenging tasks in organic syntheses. The early developed reaction protocols by Ullmann, Ullman–Goldberg, Cadiot–Chodkiewicz, Castro–Stephens, and Corey–House, utilizing elemental copper or its salts as catalyst have, for decades, attracted and inspired scientists. However, these reactions were suffering from the range of functional groups tolerated as well as severely restricted by the harsh reaction conditions often required high temperatures (150–200 °C) for extended reaction time. Enormous efforts have been paid to develop and achieve more sustainable reaction conditions by applying the microwave irradiation. The use of controlled microwave heating dramatically reduces the time required and therefore resulting in increase in the yield as well as the efficiency of the reaction. This review is mainly focuses on the recent advances and applications of copper catalyzed cross-coupling generation of carbon–carbon and carbon–heteroatom bond under microwave technology.