Synthesis, biological activity and molecular modelling studies of tricyclic alkylimidazo-, pyrimido- and diazepinopurinediones.

"since that time a few x-ray structures of a 2a ar in complex with various ligands have been reported in the protein data bank [ ] among which those co-crystallized with xanthines: xac (pdb code: 3rey) and caffeine (pdb code: 3rfm) are of great importance for our research."

"The authors wish to acknowledge Professor James P. Stables for providing pharmacological data through the Antiepileptic Drug Development Program National Institutes of Health. Financial support of this research by the Ministry of Science and Higher Education and National Science Centre, Poland (grant No. 4 P05F 014 18, grant No. NN 405 297 836 and grant DEC-2012/04/M/NZ4/00219) and by the BMBF, Germany (01EW0911) in the frame of ERA-NET NEURON is gratefully acknowledged. We would like to thank Mrs. Inge Renner and Katharina Thiemke for the technical assistance in the biological experiments."