FT-Raman and FTIR-ATR spectroscopies and DFT calculations of triterpene acetyl aleuritolic acid

•A study investigating the vibrational properties of triterpene acetyl aleuritolic acid (AAA) was carried.•Vibrational wavenumbers were predicted using Density Functional Theory calculations.•Structural information and characterization of AAA.•Study of vibrational spectra of triterpene acetyl aleuritolic acid.•A detailed description of the assignments of vibrational wavenumbers of AAA for Raman and infrared bands.

Triterpenoids comprise an important class of compounds presenting a wide range of biologically important properties. Acetyl aleutitolic acid (AAA) is a triterpenoid isolated from Croton zehntneri, with molecular formula C32H50O4. Its structure has been characterized by NMR spectroscopy, however, there are no papers available regarding its vibrational properties. The Fourier-Transform Infrared with Attenuated Total Reflectance and Fourier-Transform Raman spectra, together with Density Functional Theory calculations of AAA are reported. Vibrational spectra were recorded at 300 K in the regions 600 cm−1 to 4000 cm−1 and 40 cm−1 to 4000 cm−1, for IR and Raman, respectively. Vibrational wavenumbers were predicted using Density Functional Theory calculations with the hybrid functional B3LYP and the basis set 6-31 G(d,p). A complete assignment of vibrational modes is given.