Two new maltol glycosides and cyanogenic glycosides from Elsholtzia rugulosa Hemsl.

Two new maltol glycosides, maltol 6'-O-beta-D-apiofuranosyl-beta-D-glucopyranoside and maltol 6'-O-(5-O-p-coumaroyl)-beta-D-apiofuranosyl-beta-D-glucopyranoside, were isolated from Elsholtzia rugulosa Hemsl. along with 11 known compounds including prunasin and amygdalin. The structures were determined on the basis of spectroscopic and chemical evidence.

Facile discrimination of aldose enantiomers by reversed-phase HPLC.

One-pot reactions of aldoses with L-cysteine methyl ester and o-tolyl isothiocyanate yielded methyl 2-(polyhydroxyalkyl)-3-(o-tolylthiocarbamoyl)-thiazolidine-4(R)-carboxylates. Direct HPLC analysis of the reaction mixture and UV detection at 250 nm discriminated D- and L-enantiomers of aldoses. The reaction was applied to the determination of absolute configuration the sugar residues of an aroma precursor.