V.I. Sheichenko, O.P. Sheichenko, O.N. Tolkachev

Some published data on the nomenclature. structure and biologic activity of bisbenzylisoquinoline alkaloids of the isochondodendrine series were discussed. Experimental data of the authors on the conformation study were also given. There were studied the 1H NMR spectra of the isochondodendrine type alkaloids: cycleanine (I), norcycleanine (II), isochondodendrine (III) and isobebeeridine (tetra-O-demethyl cycleanine) (IV), their functional derivatives, their salts and quaternary ammonium compounds and the factors acting on their conformation were also discussed. The alkaloids I, III and IV were shown to possess centrosymmetric structure with the predominant pseudo-axial conformation of the N-methyl group in bases for III and IV. The alkaloids I and II form in acidic media a mixture of three isomeric salts, while III and IV produce predominant di-axial salts. Thus the stereochemistry of N-protonation was shown to be dependent on a number factors: on the substituents in the position 7 and 7´ in tetrahydroisoquinoline nucleus, on the solvents effects of (H2O, CHCl3, PhNO2, D5Py, CD3OD, Me2CO), on the acidity indexes of used acids (HCl, H2SO4, CF3COOH, AcOH) and on the condition of the salts formation. Equation formula for the quantitative calculation of diastereomeric salts ratio is proposed. Minimal potential energies of the studied compounds were calculated and the computer 3D models of the studied molecules have been constructed using the Programs MM2 and Molecular Dynamics (ChemOffice) and other Standard Programs. The list of 57 references are cited.