RESOLUTION AND CONFORMATIONAL-ANALYSIS OF DIASTEREOISOMERIC ESTERS OFCIS-2-(AMINOMETHYL)-1-CARBOXYCYCLOPROPANES AND TRANS-2-(AMINOMETHYL)-1-CARBOXYCYCLOPROPANES

(1R,2S)-, (1S,2R)-, (1R,2R)- and (1S,2S)-2-(Aminomethyl)-1-carboxycycl opropanes, conformationally restricted analogues of the neurotransmitt er gamma-aminobutyric acid (GABA), have been resolved by chromatograph ic separation of the corresponding diastereoisomeric esters which were formed between the cis- and trans-2-(acetamidomethyl)1-carboxycyclopr opanes with (R)-(-)-pantolactone. H-1 NMR, semi-empirical conformation al analysis, ab initio (DFT) structure and NMR shielding tensor calcul ations of the cis-diastereoisomers allowed the absolute configuration assignments of the cis-amino acids. (C) 1998 Elsevier Science Ltd. All rights reserved.