Diastereoisomer-selective inclusion complexation of Cinchona alkaloids with a modified beta-cyclodextrin: fluorescent behavior enhanced by chiral-tether binding. Short communication.
The molecular 1:1 complexation of cinchona alkaloids by mono(6-deoxy-6-{[(R)-1-(hydroxymethyl)propyl]amino})-beta-cyclodextrin (1) in aqueous solution has been investigated by 2D-NMR, fluorescence titration, and fluorescence-lifetime experiments. Generally, with 1 as the host, in contrast to beta-cyclodextrin proper, strong binding of quinine (2; Ka = 84,200 M(-1)) and quinidine (3; Ka = 27,300 M(-1)) at pH 6.8 was observed, as monitored by an increase in fluorescence intensity, with a fair degree of diastereoisomer discrimination (ca. 3:1). To rationalize these results, two possible cooperative complexation modes, including specific H-bonding interactions to the chiral tether of the cyclodextrin portion, are proposed.
Liu
Yu
Y
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, PR China. yuliu@public.tpt.tj.cn
Yang
Ying-Wei
YW
Zhang
Heng-Yi
HY
Hu
Bo-Wen
BW
Ding
Fei
F
Li
Chun-Ju
CJ
D001665:Binding Sites / Q000502:physiology; D002930:Cinchona Alkaloids / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D013050:Spectrometry, Fluorescence / Q000379:methods; D013237:Stereoisomerism; D047392:beta-Cyclodextrins / Q000737:chemistry* / Q000378:metabolism
D002930:Cinchona Alkaloids; D047392:beta-Cyclodextrins; C031215:betadex