DETERMINATION OF CONFIGURATION OF MONOSACCHARIDES BY HPLC ON DIASTEREOISOMERIC 1-DEOXY-1-(N-ACETYL-α-METHYLBENZYLAMINO)ALDITOL ACETATES

Abstract

Acyclic diastereoisomers, 1-deoxy-1-(N-acetyl-α-methylbenzylamino)alditol acetates, are readily obtained by reductive amination of sugars with chiral α-methylbenzylamine in the presence of sodium cyanoborohydride. Ten pairs of enantiomers of common monosaccharides are resolved by an adsorption HPLC on the diastereoisomers.

On the Chemical Constituents of Dipsacus asper

“…In the 1 H-and .7 (C-12a)] suggested the presence of a 4-hydroxymethyl-1,3-dioxolane moiety, and this was further confirmed by long-range correlations from H-13a to both C-7a and C-14a, and H-14a to C13a in HMBC spectrum. For unit B, the 13 C-and 1 H-NMR spectroscopic data were almost identical to those of loganin 15) except for downfield shifts of C-7b (ϩ3.0 ppm) and H-7b, as a result of a deshielding effect due to esterification of the C-7b OH-group. Consequently, unit A and unit B are linked by an ester bond between C-7b and C-11a, this being confirmed by HMBC analysis.…”

“…The combined Table 4). The active fraction XD-B-3 (30 g) was applied to a Sephadex LH-20 column using Identification of Sugars According to the reported procedures in the literature, 15) the identification of the sugar was determined by comparison of the retention times of derivatives of sugars obtained upon the hydrolysis mixture with those of standard samples using HPLC, which were performed with an Inertsil sil-100A column (250ϫ4.6 mm, 5 mm, Dikma) eluting with n-hexane/ethanol (95 : 5); flow rate 1.2 ml/min; detection at 230 nm, 0.04 aufs. The retention times of the derivatives of the sugars were as follows: Dglucose 40.0 min, L-glucose 39.0 min.…”

New Constituents from the Leaves of Morinda citrifolia

“…Its molecular formula was determined as C 16 [4][5][6] The b-anomeric configuration for the glucose was judged from its large 3 J H1,H2 coupling constant (Jϭ7.9 Hz). HMBC correlations (between C-1/H-1Ј and H-1/C-1Ј) and a NOESY correlation (H-1/H-1Ј) (Fig.…”

“…These fractions were also purified repeatedly by preparative HPLC (Capcellpak C18 UG 80, 30ϫ250 mm) to give 2 (12.3 mg), 5 (16.8 mg), 7 (7.6 mg), 8 (2.7 mg), 9 (4.3 mg), 10 (3.7 mg), 11 (4.1 mg), 12 (4.4 mg), 13 (8.0 mg), 14 (9.8 mg), 15 (7.4 Table 2. Determination of the Absolute Configuration of the Glucose Unit of Citrifoside (1) [4][5][6] A solution of 1 (5 mg) in 1 M HCl (dioxane-water, 1 : 1, 2 ml) was heated at 100°C for 2 h. The reaction mixture was concentrated, dissolved in water, passed through a Waters Sep-Pak Light C18 cartridge, and evaporated to furnish the glucose residue. After dissolving in water (1 ml), the solution of (S)-a-methylbenzylamine (5 mg) and 2-picoline-borane complex 25) (14 mg) in EtOH (1 ml) was added.…”

Fargosides A-E, Triterpenoid Saponins from Holboellia fargesii.

“…The monosaccharides, including their configurations, were identified by HPLC analysis following their conversion to the 1-[(S )-N-acetyl-a-methylbenzylamino]-1-deoxy-alditol acetate derivatives. 6,7) The interglycosidic linkage and the position of the sugar moiety attached to the aglycon were determined unambiguously by HMBC spectrum. The correlation between H-1 (d 5.27) of Xyl and C-2 (d 84.0) of Glc indicated that Xyl was linked to C-2 of Glc.…”