Vibrational Spectra and Stable Conformations of (1RS, 5RS, 6SR)-6-Methoxycarbonylamino-(5'-methoxyindolo[2,3-b])bicyclo[3.2.1]oct-2-en

The IR and Raman spectra of (1RS,5RS,6SR)-6-methoxycarbonylamino-(5'-methoxyindolo[2,3-b])bicyclo[3.2.1]oct-2-ene are investigated. Optimized structures and harmonic force fields of stable conformers are calculated with the density functional theory using the B3LYP and BVP86 functionals with a number of basis sets of varied completeness. Based on the calculations, the spectra are interpreted in detail, and the frequencies of the fundamental oscillations of the most stable forms of the compound under study are identified. The theoretical spectra are analyzed and compared to the experimental data.