Hexose → (2R,3R,4S,5S)-2,3,4,5-tetrahydroxyhexanal

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Reaction Steps

Saponin 13 gave m/z1243.6110 for C59H96NaO26 by HRFABMS. Negative-ion FABMS indicated the loss of one pentose, one hexose, two deoxyhexoses, and one glucuronic acid residue. Acid hydrolysis of 13 furnished the aglycone and monosaccharide components, glucuronic acid, galactose, rhamnose and arabinose by TLC analysis. The sugars of 13 were evidenced by five anomeric proton and carbon signals in 1H and 13C NMR spectra (Table 4). By 13C NMR, the two methyl carbon signals at δ 18.80 and 18.00 and proton signals at δ 1.24 and 1.28 (3H each, d, J=6.5 Hz) indicated that 13 contained two 6-deoxy sugars. By 13C NMR, all of the monosaccharides were pyranoses. The anomeric configurations were fully defined from their 3JH1-H2 coupling constants as well as from NOE correlations observed in the ROESY spectrum (Hosny et al., 1999).

Provenance & Evidence