Synthesis of 2-tetrafluoropyridyl-4,5-disubstituted 1,2,3-triazoles.

Khalil Beyki,Reza Heydari,Malek Taher Maghsoodlou

doi:10.1186/s40064-016-3398-4

Abstract

By cycloaddition reaction of sodium azide with chalcone in the presence of CuO as a catalyst in DMF a 1,2,3-triazole are prepared in reaction with pentafluoropyridine to give 2-(tetrafluoropyridin-4-yl)-1,2,3-triazole derivatives in good yields and high regioselectivity. The regioselectivity of the compounds are confirmed by 19F-NMR and other spectroscopy.Graphical

Highlights

Perfluorocarbons have been used as building blocks in the pharmaceutical industry and in material science due to their unique properties (Kenneth 2006; Bruce 2001)
Pentafluoropyridine in which all the hydrogen atoms in pyridine ring have been replaced by fluorine atoms are highly susceptible towards nucleophilic attack owing to the presence of several highly electronegative fluorine atoms and nitrogen hetero atom; the chemistry of pentafluoropyridine is dominated by nucleophilic aromatic substitution processes and new chemistry continues to emerge (Iwao 2009; Reza et al 2008; Mark et al 2013; Van Ba and Donald 2012)
The order of nucleophilic attack for pentafluoropyridine is established to be para > ortho > meta positions, so the reactions of pentafluoropyridine with some nucleophile occur selectively at the para position as this site is most activated towards nucleophilic additions to afford of 4-substited

Summary

Introduction

Perfluorocarbons have been used as building blocks in the pharmaceutical industry and in material science due to their unique properties (Kenneth 2006; Bruce 2001). Baohua Chen and coworker’s reported the synthesis of N-2-aryl-substituted-1,2,3-triazoles and arylation in the last step (Yuanqing et al 2012). We reported the synthesis of 4-substituted2,3,5,6-tetrafluoropyridine derivatives by the reaction of pentafluoropyridine with malononitrile, 1-tetrazole5-thiol, piperazine (Khalil et al 2015), hydroxylated naphtoquinones and hydroxylated antraquinones (Khalil et al 2016). Results and discussion In this research, we describe the synthesis of 2-tetrafluoropyridyl-4,5-disubstituted-1,2,3-triazoles via Diels–Alder cycloaddition reaction of sodium azide and 1,3-diphenylprop-2-en-1-one (chalcone) and nucleophilic substitution reactions with pentafluoropyridine in DMF as solvent.

Results

Conclusion