Spectral characterization of fluconazole

Abstract

Reference 1H, 19F and 13C NMR, mass, IR and Raman spectra are provided to the open literature for the first time for the potent antifungal agent fluconazole, α-(2,4-difluorophenyl)-α-(1 H-1,2,4-triazol-1-ylmethyl)-1 H-1,2,4-triazole-1-ethanol. The 1H, 19F and 13C NMR spectra were analyzed in detail to attribute shifts, including 19F chemical shifts and C-F and F-F coupling constants. The EI mass spectrum, although rich in fragment ions, lacked a molecular ion. FAB and MS/MS experiments were undertaken in support of the structure in order to validate the EI spectrum as a reference mass spectrum. IR and Raman spectra are compared to show the complementary nature of their features and discussed in terms of principal group vibrations. NMR and vibrational data together with assignments are summarized in tabulated form for convenience of use. All these data are consistent with the structure of fluconazole.