Microwave-assisted regioselective synthesis and isomerization of 6-O-vanillyl- and 6-O-iso-vanillyl hexoses and studies of their activities as radical scavengers by EPR spectroscopy

Four 6-O-substituted saccharides, namely 6-O-vanillyl-d-glucose 1, 6-O-vanillyl-d-mannose 2, 6-O-iso-vanillyl-d-glucose 3 and 6-O-iso-vanillyl-d-mannose 4 have been synthesized. Synthesized saccharide derivatives have been subsequently used in Mo(VI)-catalyzed stereospecific isomerizations yielding compounds with potential radical scavenging activity. In order to accelerate intramolecular isomerization rates and conversions microwave irradiation was used. Synthesized products were obtained with excellent stereoselectivity in good conversions and were tested by EPR spectroscopy for radical scavenging activity.

Figure optionsDownload as PowerPoint slide

6-O-(4-Hydroxy-3-methoxybenzyl)-d-glucoseC14H20O8Ee = 100%[α]D=+33.0[α]D=+33.0 (c 1.0, MeOH)Source of chirality: d-glucose

6-O-(4-Hydroxy-3-methoxybenzyl)-d-mannoseC14H20O8Ee = 100%[α]D=+15.0[α]D=+15.0 (c 1.0, MeOH)Source of chirality: d-mannose

6-O-(3-Hydroxy-4-methoxybenzyl)-d-glucoseC14H20O8Ee = 100%[α]D=+31.0[α]D=+31.0 (c 1.0, MeOH)Source of chirality: d-glucose

6-O-(3-Hydroxy-4-methoxybenzyl)-d-mannoseC14H20O8Ee = 100%[α]D=+13.0[α]D=+13.0 (c 1.0, MeOH)Source of chirality: d-mannose