Roger Simonsson

Synthesis of the enantiomers of felodipine and determination of their absolute configuration

Abstract The pure enantiomers of felodipine, 1 , have been synthesized by chromatographic separation of diastereomeric esters with (R)-1-(p-toluenesulfonyl)-3-trityloxypropan-2-ol, 3 , as an easily removable chiral auxiliary. Absolute configurations have been deduced via X-ray crystallography on a (R)-mandelic acid ester, 9B .

Degradation of perfluoroacyl derivatives of tocainide and some of its analogues in the presence of an excess of anhydride reagent

Abstract The perfluoroacylation of tocainide has been studied. The initially formed perfluoroacylamides were found to be degraded by an excess of perfluoroacyl anhydride. The reaction of tocainide with heptafluorobutyric anhydride gave similar results in six different solvents. Comparable amounts of decomposition occurred with trifluoroacetyl and pentafluoropropionyl anhydrides as reagents. Six new products were separated by gas chromatography and their structures tentatively assigned based on comparison with a deuterated analogue and mass spectral analysis including high resolution measurements: dehydrated and dehydrogenated heptafluorobutyryl (HFB)-tocainide, “apparent” pyruvic xylidide which still retains the perfluoro group, dehydrated HFB-tocainide and dehydrogenated HFB-tocainide. In the presence of water, these compounds could be quantitatively converted into HFB-tocainide with loss of tocainides chirality. Studies with some tocainide analogues having a primary amino group and a secondary amide demonstrated that these functional groups are required to give labile HFB derivatives. On the contrary, stable derivatives of tocainide were formed with heptafluorobutyryl chloride and N-methyl-bis(heptafluorobutyramide).