Crystal structure and theoretical study of IR and H-1 and C-13 NMR spectra of cordatin, a natural product with antiulcerogenic activity

摘要

Cordatin is a furan diterpenoid with a clerodane skeleton isolated from Croton palanostigma Klotzsch (Euphorbiaceae). This natural product shows Significant antiulcerogenic activity, similar to cimetidine (Tagamet (R)), a compound used for the treatment of peptic ulcers. The crystal structure of cordatin was obtained by X-ray diffraction and its geometrical parameters were compared with theoretical calculations at the B3LYP theory level. The IR and NMR (H-1 and C-13 chemical shifts and coupling constants) spectra were obtained and compared with the theoretical calculations. The B3LYP theory level, with the 6-31G(d,p) and 6-311G(d,p) basis set, provided IR absorption values close to the experimental data. Moreover, theoretical NMR parameters obtained in both gas phase and chloroform solvent at the B3PW91/DGDZVP, B3LYP/6-311+G(2d,p), and B3PW91/6-311+G(2d,p) levels showed good correlations with the experimental results. (C) 2008 Wiley Periodicals, Inc.