GABA-B AGONISTS - ENANTIOMERIC RESOLUTION OF 4-AMINO-3-(5-CHLOROTHIEN-2-YL)BUTYRIC ACID AND ANALOGS ON CHIRAL CROWN-ETHER STATIONARY-PHASE

The enantiomeric resolution of 4-amino-3-(5-chlorothien-2-yl)butyric a cid, an analogue of baclofen [4-amino-3-(4-chlorophenyl)butyric acid], was examined by HPLC using a chiral stationary phase consisting of a crown ether and perchloric acid-methanol as the mobile phase. Optimiza tion of the separation was achieved by variation of temperature, pH an d eluent composition. The absolute configuration may be assigned by co mparison with authentic enantiomers of baclofen of known absolute conf iguration. The best results obtained were alpha = 1.15 and R(s) = 2.72 at 20 degrees C with HClO4 (pH 1.3)-CH3OH (90:10). The study was exte nded to analogues, viz., 3-(substituted thienyl) and 3-(substituted fu ranyl)-4-amino acids.