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Circular dichroism of 1,3‐dioxane‐type (2′‐naphthyl)methylene acetals of glycosides
Author(s) -
Kurtán Tibor,
Borbás Anikó,
Szabó Zoltán B.,
Lipták András,
Bényei Attila,
Antus Sándor
Publication year - 2004
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.20019
Subject(s) - chemistry , chromophore , methylene , stereochemistry , circular dichroism , crystallography , naphthalene , photochemistry , medicinal chemistry , organic chemistry
The CD spectra are reported for a series of 1,3‐dioxane‐type 4,6‐O‐(2′‐naphthyl)methylene acetals of carbohydrates with and without interacting aromatic protective groups on the C‐1, C‐2, and C‐3 hydroxy groups. In the absence of interacting chromophores, the signs of the 1 B transitions are not sensitive to the configuration of C‐4, while the signs of the weak 1 L a bands are opposite in the galacto and gluco derivatives. The equatorial parallel conformation is found to be the preferred conformation of the 2‐naphthyl group in the solid state by X‐ray diffraction. The intense 1 B a and 1 B b transitions of the naphthalene chromophore allowed a safe configurational assignment by exciton coupled interaction with the aromatic protective groups in para ‐methoxyphenyl‐β‐D‐glycosides. The origin of the observed CEs were deduced and the additivity of the interactions was studied. The direction of the hydrogenolytic cleavage of 4,6‐O‐(2′‐naphthyl)methylene acetal of carbohydrates could also be detected by the 1 B b transition of the 2‐naphthyl chromophore. Chirality 16:244–250, 2004 . © 2004 Wiley‐Liss, Inc.