Abstract
In this report, the recognition points of tryptophan by 2-hydroxypropyl-alpha-cyclodextrin (HPαCD) are presented. This cyclodextrin exhibited greater thermodynamic chiral selectivity towards DL-tryptophan than the hydroxypropylated beta form. FTIR spectroscopy was used to tentatively evidence this chiral discrimination in solid state HPαCDTrp complexes. An inclusion complex was only detected for the HPαCD-DTrp sample, while HPαCD-LTrp immediately decomposed after crystallization, which left a mechanical mixture of tryptophan and cyclodextrin.
Keywords: Chiral recognition, NMR, FTIR, cyclodextrin, tryptophan, thermodynamic chiral selectvity