Synthesis, molecular structure and biological activity of bromobenzylgermatranes

Abstract

The new series of benzylgermatranes ▪, R=H ( I), 2-Br ( II), 3-Br ( III), 4-Br ( IV), has been obtained to study the influence of a substituent position on coordination of the germanium atom, the values of bond angles and neurotropic activity. Compounds I– IV were prepared by insertion of GeBr 2 into carbon–bromine bond of the corresponding benzylbromide or bromobenzylbromide in refluxing toluene, conversion of benzyl- or bromobenzyltribromogermanes into triethoxy derivatives by alcoholysis, and transalkoxylation with triethanolamine. The crystal structure of compounds I– IV was studied via the X-ray diffraction method. The intramolecular donor–acceptor bond N→Ge in benzylgermatranes (2.175–2.219 Å) is shorter than that in tolylgermatranes (2.212–2.230 Å). Biological investigations have demonstrated that all benzylgermatranes ( I– IV) are low toxic compounds (LD 50>1000 mg kg −1) with high anaesthetic and anti-Corazol activity. Benzylgermatrane ( I), 3-bromobenzylgermatrane ( III) and 4-bromobenzylgermatrane ( IV) improve memory processes and completely prevent animals from retrogradal amnesia (RA) caused by electroshock.