Chiral Recognition of Thiaheterohelicenes by Alkyl β-D-Pyranoside Micelles. Influence of Extension of Helix

• Published in: Chemical & pharmaceutical bulletin Vol. 49; no. 1; pp. 49 - 53
• Main Authors: NAKAGAWA, Hiroko, GOMI, Kanae, YAMADA, Koh-ichi
• Format: Journal Article
• Language: English
• Published: Tokyo The Pharmaceutical Society of Japan 2001; Maruzen
• Subjects: alkyl β-D-pyranoside; Chemistry; chiral recognition; Circular Dichroism; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Heterocyclic Compounds - chemistry; Magnetic Resonance Spectroscopy; micellar effect; Micelles; Micelles. Thin films; Molecular Structure; Pyrans - chemistry; Stereoisomerism; thiaheterohelicene; Molecular rigidity; Structure effect; Circular dichroism spectrum; Glucoside; Steric hindrance; Disaccharide; Hydrogen 1; Sulfur heterocycle; Chirality; Helicene; Glycoside; Micellar solution; NMR spectrum; Recognition
• ISSN: 0009-2363; 1347-5223
• DOI: 10.1248/cpb.49.49

Chiral recognition of alkyl β-D-pyranoside micelles toward [7] and [5] heterohelicenes possessing helical structures was investigated by 1H-NMR and CD (circular dichroism) spectroscopy. In dodecyl maltopyranoside micellar solution, P and M enantiomers of tetrathia[7]heterohelicene (7TH), which have rigid and stable helixes, manifested different chemical shifts in their 1H-NMR spectra due to differences in the diastereomeric interactions, implying that the micelles undergo stronger recognition toward the M enantiomer than the P enantiomer. On the other hand, in octyl glucopyranoside micellar solution, trithia[5]heterohelicene (5TH) and two kinds of its derivatives which are rapidly equilibrated between the enantiomers in solution, gave no distinctly resolved 1H-NMR peaks for either enantiomer even at a lowered temperature. However, these racemic [5]heterohelicenes in the micelles did develop induced CD absorptions owing to a displacement of the equilibrium, suggesting from the signs of their Cotton effects that the micelles prefer the M enantiomer to its antipode in conformity with the 1H-NMR results of 7TH.