Circular Dichroism and the Anomeric Configuration of C -Glycofuranosyl-2-Phenyl-2 H -1,2,3-Triazoles

Abstract

Circular dichroism spectra of a series of 4-(tetra-hydroxy-tetryl-1-yl)2-phenyl-2H-1,2,3-triazoles were measured and the sign of their Cotton effects was correlated to the absolute configuration of the hydroxyl group alpha to the triazole base moiety. Those having the D-glycero-configuration in their Fischer projection formula show positive Cotton effect and those with the L-glycero-configuration show negative Cotton effect. This correlation was extended for the assignment of the anomeric configuration of the corresponding glycofuranosyl-C-nucleosides.

Circular dichroism as a reliable tool for anomeric assignment of glycosyl‐2‐phenyl‐2H‐1,2,3‐triazole C‐nucleoside analogs. A rule for prediction of their anomeric configuration

“…In addition, these compounds did not obey Hudson isorotation rules 14,15 for optical rotation (the aanomer should have positive or higher specific rotation and the b-anomer have negative or lower specific rotation). The glycofuranosyl C-nucleoside analogs 4 showed similar deviation to Hudson isoratotion rules at the D-line.…”

“…This correlation is in accordance with the correlation obtained by El-Khadem 9,10 for the lower carbon atom analogs. 4 The CD spectra of compounds 1-6 showed single Cotton effect (300-225 nm) at the maximal UV absorption (see Fig. 1 The CD of compound 5, having p-bromine substituent, showed red shift to higher wave length compared to the unsubstituted analog 1 (from 262.6 to 270.4 nm).…”

“…In addition, this CD assignment for 7-10, is in accordance with the correlation previously obtained for D,L-glycofuranosyl C-nucleosides. 4 Therefore, it may be taken as a general criterion for the assignment of 4-(glycofuranosyl, 5 0 -hydroxymethylfuranosyl and pyranosyl)-2-phenyl-2H-1,2,3-triazole C-nucleosides, in general. This may be stated in the form of CD C-nucleoside triazole rule as follows: \glycosyl-2-phenyl-2H-1,2,3-triazole C-nucleosides having positive Cotton effect at their maximal UV absorption are assigned b-D-configuration.…”

“…The development of chiroptical CD spectrometers by facilitating measurements at low wavelength region (down to 163 nm), base line stability, and low noise level 2 has furthered the study of optically active molecules. 3 In a previous publication, 4 the chiroptical properties of a series of D-and L-4-(tetrahydroxytetryl-1-yl)-2-phenyl-2H-1,2, 3-triazoles and the corresponding glycofuranosyl C-nucleoside analogs were studied. The Cotton effect at the maximal UV absorption of the acyclic analogs is correlated with the absolute configuration of the hydroxyl group a to the triazole base moiety.…”

Studies on the dehydrative cyclization of epimeric 4‐(L‐xylo and L‐lyxo‐tetritol‐1‐yl)‐2‐phenyl‐2H‐1,2,3‐triazoles. Circular dichroism and NMR assignment of the formed anomeric C‐nucleoside L‐threofuranosyl triazole analogs

“…13 C NMR spectra were recorded with Bruker 600 MHz instrument at 150.9 MHz. Assignment of peaks were verified by 2D and 1 H- 13 C COSY experiments.…”