A critical view on antimalarial endoperoxide QSAR studies.

Malaria is one of the most dangerous diseases in developing countries. The chemotherapy of malaria has been based on drugs developed more than half a century ago. These drugs are continuously losing their efficacy, mainly due to multi-drug resistance developed by the malaria-causing parasite. In the last three decades, artemisinin and artemisinin-like compounds have proven to be efficient alternatives to the chemotherapeutic control of malaria. These facts have led to an increasing interest in the development of Quantitative Structure Activity Relantioship (QSAR) models for these compounds. This work presents a critical view on some QSAR models, and shows that, due to lack of a rigorous selection of the descriptors entering the models, most of them are unable to accurately indicate the molecular cause of biological activity. Some reasons for the weakness of the published models are discussed.

DFT studies of structure and vibrational frequencies of isotopically substituted diamin uranyl nitrate using relativistic effective core potentials.

The infrared and Raman spectra of UO(2)(NH(3))(2)(NO(3))(2) with (14)NH(3)/(15)NH(3) isotopic substitution were measured. The structure was optimized and the vibrational spectrum was calculated by DFT (B3LYP/6-31G(d)) methodology using relativistic effective core potential for U atom. The results for force constant and vibrational frequencies support the experimental assignments and the proposed model, mainly in the far-infrared region, where the metal-ligand bond and lattice vibrations are observed. Based on the theoretical findings and the observed spectra a structure of distorted D(2h) symmetry with the nitrate group acting like bidentate ligands for the UO(2)(NH(3))(2)(NO(3))(2) is proposed.