Synthesis and NMR studies of chiral 4-oxazolidinones and rhodanines
摘要:
Sterically hindered N-(o-tolyl) and N-(o-chlorophenyl) substituted 2-thioxo-4-oxazolidinones 1 and-thiazolidinones (rhodanines) 2 forming enantiomers by partial rotation around the C-N bond are synthesized. Their chirality is proven by the presence of diastereotopic protons (or carbon atoms) detected by H-1 or C-13 NMR (1c, 2c). In the presence of (S)-(+)-1-(9-anthryl)-2,2,2-trifluoroethanol as an auxiliary the enantiomers showed H-1 shift differences of 0.01 ppm for otherwise isochronous nuclei.