Z. Chilmonczyk, J. Cybulski, A. Szelejewska-Woźniakowska
Dec 2, 1996
Citations
0
Influential Citations
14
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract Conformations of piperazine rings in 8-{4-[4-(2-pyrimidyl)-1-piperazinyl]butyl}-8-azaspiro[4.5]-decane-7,9-dione (buspir-one — 1 ) and its two analogues 8-{4-[4-(2-quinolinyl)-1-piperazinyl]butyl}-8-azaspiro[4.5]-decane-7,9-dione (kaspar — 2 ) and 4,4-dimethyl-1-{4-[4-(2-quinolinyl)-1-piperazinyl]butyl}-2,6-piperidinedione (mesmar — 3 ) (Fig. 1) have been studied with the aid of 1 H NMR and 13 C NMR spectra. For free bases the two bands corresponding to piperazine hydrogen atoms in the spectra broaden considerably with a decrease in temperature to divide into four separate bands, indicating the presence of a dynamic exchange process. A similar dynamic process, but for higher temperatures, was observed for buspirone ( 1 ), kaspar ( 2 ) and mesmar ( 3 ) hydrochlorides. Proton and carbon atom resonance lines have been assigned with the aid of 2D COSY and 2D HETCOR two-dimensional spectra.