Yeni trisiklik glikozil donörler ve glikozilasyon reaksiyonlarına uygulamaları

In this research, D-mannose, D-galactose and D-glucose were used as starting sugars. These experimental researches were based upon glycosyl donors and glycosylation reactions of these basic sugars. As the result of the reaction of D-mannose and anhydrous chloral, 1,2-O-trichloroethylidene-α-D-mannofuranose was obtained. 1,2-O-trichloroethylidene-α-D-mannofuranose was reacted with 2,2-dimethoxypropane to afford 5,6-O-isopropylidene-1,2-O-trichloroethylidene-α-D-mannofuranose. In a further step, as the result of the reaction between 5,6-O-isopropylidene-1,2-O-trichloroethylidene-α-D-mannofuranose with potassium tert-butoxide 1,2,3-O-dichloroethylidene-5,6-O-isopropylidene-α-D-mannofuranose which was a tricyclic glycosyl donor was obtained. This tricyclic glycosyl donor was applied to a glycosylation reaction with methanol and octanol in the presence of a Lewis acid. Similarly, beginning with D-glucose and D-galactose, respectively 5,6-O-isopropylidene-1,2-O-trichloroethylidene-α-D-glucofuranose and 5,6-O-isopropylidene-1,2-O-trichloroethylidene-α-D-galactofuranose were prepared. In addition to D-mannose's sequence of reactions in order to obtain a tricyclic glycosyl donor, these two products were oxidized with pyridinium dichromate. In the next sequence, reduction with sodium borohydride afforded 1,2,3-O-dichloroethylidene-5,6-O-isopropropylidene-α-D-allofuranose and 1,2,3-O-dichloroethylidene-5,6-O-isopropropylidene-α-D-gulofuranose. These products were used to form a tricyclic glycosyl donor. In the next steps glycosyl donors and glycosylation reactions were applied using the same process.