Substituted 4-(1H-1,2,3-triazol-1-yl)-tetrafluorobenzoates: Selective synthesis and structure

• Convenient method for the synthesis of 1,4-substituted triazolyl tetrafluorobenzoates.
• CuBr (5 mol%), Et3N in CH2Cl2 are optimal for CuAAC.
• Electron donor and electron acceptor substituents in triazolyl cycle are present.
• Molecular structure of 4-Ph(C2HN3)-4-C6F4CO2Et was investigated.
• New NMR procedure for establishment of C-4 substituted 1-aryl-triazoles is elaborated.

Regioselective, simple and fast synthesis of a series of [2 + 3]-cycloaddition products, 2-11, 4-(4-RC2HN3)C6F4CO2Et (2: R = Ph; 3: R = CMe2OH; 4: R = CH2OH; 5: R = CO2Et; 6: R = n-C5H11; 7: R = CH2O-o-C6H4CHO; 8: R = CH2O-p-C6H4NHBoc; 9: R = CH2O-p-C6H4CH2OH; 10: R = CH2O2CC6F5; 11: R = p-C6H4Bu-t), in reaction between ethyl 4-azido-2,3,5,6-tetrafluorobenzoate, 1, and a number of substituted alkynes was elaborated under conditions of copper-catalyzed click chemistry reaction. The optimized conditions include application of CuBr and Et3N in dichloromethane. The structure of compounds 2-11 was investigated in solution by 1D and 2D NMR and IR spectroscopy. The molecular structure of 2 in solid state was established by X-ray analysis.

A number of 1,4-substituted triazolyltetrafluorobenzoates containing both electron donor or electron acceptor substituents was obtained under conditions of copper catalyzed alkyne–azide cycloaddition. The method is tolerant to various groups.Figure optionsDownload as PowerPoint slide