DIRECT ENANTIOMER SEPARATIONS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH CHIRAL UREA DERIVATIVES AS STATIONARY PHASES

The chromatographic properties of urea derivatives derived from (S)- and (R)-1-(alpha-naphthyl)ethylamine with (S)-valine, (S)-tert.-leucine, (S)-proline and (S)-indoline-2-carboxylic acid bonded to 3-aminopropylsilica gel as chiral stationary phases were examined by HPLC to investigate the effect of the structure of the amino acid moiety. The specific enantiomer separation of various racemic compounds including alcohols, esters, amines, amino alcohols, carboxylic acids and amino acids was accomplished on these phases using normal mobile phases. The effect of the stereochemical structure in these urea derivatives on chiral recognition is discussed.