Determination of absolute configuration in 4-aryl-3, 4-dihydro-2(1H)-pyrimidones by high performance liquid chromatography and CD spectroscopy.

The absolute configuration of three 4-aryl-3, 4-dihydro-2(1H)-pyrimidones (Biginelli compounds, DHPMs) was established by comparison of the typical circular dichroism (CD) spectra of individual enantiomers with reference samples of known absolute configuration. The enantiomers were obtained by semipreparative separation of racemic mixtures on a Chiralcel OD-H chiral stationary phase. The method was used to establish the enantiopreference of various lipases in biocatalytic kinetic resolution experiments employing activated DHPM esters.

Sleep alterations in ischemic stroke.

In 19 patients with cerebral infarctions in the middle cerebral artery territory, investigations of sleep using a mobile EEG recording system were performed. Sleep was found to be markedly altered compared to a normal group. Although an increase of time in bed and sleep period time was observed, total sleep time did not rise in a parallel manner, so that a distinct reduction of the sleep efficiency index was found. This increase of quantitative parameters was particularly caused by a higher amount of NREM time, whereas REM sleep was found to be deeply suppressed. Regarding the different NREM sleep stages, stage 0 (time spent awake during the night) and stage 1 had increased, whereas stage 4 was reduced. Interhemispheric differences were noticed referring to the sleep period time, which was found to be increased particularly in right-sided infarctions (because of an increase of NREM time) and a reduction of REM sleep in lesions of the right hemisphere (worsening of the REM to NREM ratio). Slow-wave sleep (stage 4), on the contrary, was found to be decreased in infarctions of the left hemisphere. These results support the hypothesis of a REM-inducing and regulating function of the right hemisphere and will lead to a new understanding of sleep-controlling mechanisms.