In this work new derivatives of L-ascorbic acid (Vitamin C ) have been stynthezized . These derivatives have been obtained by the esterfication .Selective esterfication of C-3 and C-2 hydroxyl group required protecting the two hydroxyl group at 5,6-position by conversion of vitamin C to 5,6-O-isopropylidene derivative (10)3- (acetyl salicyloyl)-5,6 –O-isopropylidene-L-ascorbic acid (19) was synthesized by treatment of (10) with acetyl salicyloyl Chloride (18) .2,3-di(acetyl salicyloyl)-5,6 –O-isopropylidene-L-ascorbic acid (20) was synthesized by treatment of (10) with two moles of acetyl salicyloyl Chloride (18) or treatment of (19) with one mole of acetyl salicyloyl Chloride (18).2,3,5,6 -Tetra (acetyl salicyloyl)-5,6-L-ascorbic acid (21) was synthesized by treatment of vitamin C with four moles of acetyl salicyloyl Chloride (18)The purity of the compounds were characterized by thin later chromatography (TLC) and infrared spectroscopy (IR).The drug released study for hydrolysis of compounds (19,20,21) was carried out using different buffer at pH (2,4,6,8,10,12) over 30 hours at different intervals using UV spectroscopy which showed that these compounds were hydrophobic , but a period of 8-13h post starting to be hydrophilic . The released aspirin was increased as the pH is increased and extended time The biochemical tests revealed that the evaluated compounds (19,20,21) showed non competitive inhibition behavior to the activity of acetyl choline esterase (AChE) enzyme while these compounds showed an activation on alkaline phosphatase and acid phosphatase enzymes activity .Bacterial inhibition zone revealed a positive inhibitory impact .The In vivo study was carried out by (1.5 g) oral administration of the three compounds (19,20,21) and measurement of aspirin concentration in rabbits blood after (2,3,4,6,8,10 ) hrs. showing that the highest aspirin concentration was found after 4 hrs. of administration .
