Chiral discrimination of 2‐arylalkanoic acids by (1S,2S)‐1‐aminoindan‐2‐ol and (1S,2S)‐2‐aminoindan‐1‐ol: Correlation of the relative configuration of the amino and hydroxy groups with the pattern of a supramolecular hydrogen‐bond network in the less‐soluble diastereomeric salt

Abstract

AbstractThe diastereomeric resolution of 2‐arylalkanoic acids with enantiopure trans‐1‐aminoindan‐2‐ol and trans‐2‐aminoindan‐1‐ol were studied. Enantiopure trans‐1‐aminoindan‐2‐ol had a moderate resolving ability for 2‐arylalkanoic acids having a naphthyl group as an aryl substituent at the α‐position, while enantiopure trans‐2‐aminoindan‐1‐ol had a moderate‐to‐high resolving ability for a wide variety of the acids having a methyl group as an alkyl substituent at the α‐position. The crystal structures of the corresponding less‐soluble salts revealed that a reinforced columnar hydrogen‐bond network was formed in the less‐soluble salts with trans‐1‐aminoindan‐2‐ol, while a rather stable hydrogen‐bond sheet was generated with the assistance of water molecules in the less‐soluble salts with trans‐2‐aminoindan‐1‐ol. These results suggest that not only the relative configuration but also the position of the hydrogen‐bonding groups in resolving agents have a considerable effect on the structure of the less‐soluble salts. The difference in favorable hydrogen‐bond structure determined the adaptivity to the structural feature of target racemic 2‐arylalkanoic acids in the resolution by trans‐1‐aminoindan‐2‐ol and trans‐1‐aminoindan‐2‐ol, respectively. Chirality 15:564–570, 2003. © 2003 Wiley‐Liss, Inc.