Synthesis of M + 4 Stable Isotopomers of Ergometrine and Ergometrinine.

The priority ergot alkaloids ergometrine and ergometrinine are highly toxic mycotoxins naturally occurring in different types of grains (i.e. rye, wheat, rice), as well as grain-based foods and, therefore, have gained increasing importance for food safety over the last years. The application of HPLC-MS/MS for the analysis of ergot alkaloids in food presupposes the availability of isotopically labelled internal standards. Thus, a multistep synthesis was developed for ergometrine-(N-13CD3) and its epimer ergometrinine-(N-13CD3) with a mass shift of four units compared with the parent compounds. The synthesis is based on the preparation of stable isotope labelled lysergic acid that was coupled with (S)-alaninol. The chemical synthesis of both compounds has been achieved in six steps with an overall yield of 1 % (ergometrine-(N-13CD3)) and 0.6 % (ergometrinine-(N-13CD3)), respectively. Structural identification was performed by MS analysis as well as 1H and 13C NMR.

Resolution of 1-(2-naphthyl)ethanol by a combination of an enzyme-catalyzed kinetic resolution with a fluorous triphasic separative reaction.

[reaction: see text] Kinetic resolution of a fluorous ester rac-1 with Candida antarctica B lipase provided a mixture of enantioenriched alcohol (R)-2 and fluorous ester (S)-1. The mixture was subjected to a fluorous triphasic reaction to give both enantiomers of 1-(2-naphthyl)ethanol 2 in high ee without chromatographic separation or fluorous-organic liquid-liquid extractive purification.

Combining lipase-catalyzed enantiomer-selective acylation with fluorous phase labeling: a new method for the resolution of racemic alcohols.

Lipase-catalyzed acylation of racemic alcohols with a highly fluorinated acyl donor allows their kinetic resolution accompanied by the simultaneous enantiomer-selective fluorous phase labeling. Both the tagged and the untagged enantiomer can be separated without chromatography by a very efficient partition between a fluorous and an organic phase. The method has been successfully applied to the resolution of typically racemic secondary alcohols of low molecular weight. The fluorous label can be recovered quantitatively.

Separation of Enantiomers by Extraction Based on Lipase-Catalyzed Enantiomer-Selective Fluorous-Phase Labeling.

No chromatography is necessary to separate a racemic alcohol into its enantiomers. A highly fluorinated acyl residue was tranferred in an enantiomer-selective manner onto a racemic alcohol in the presence of a lipase [Eq. (1)]. The labeled enantiomer was separated from the unlabeled one by a simple but very efficient partition between fluorous and organic phases.