STUDIES ON SIALIC ACIDS .28. SYNTHESIS OF DISACCHARIDE NUCLEOSIDE DERIVATIVES OF 3-DEOXY-D-GLYCERO-D-GALACTO-2-NONULOSONIC ACID (KDN)

The reaction of benzyl 4,5,7,8,9-penta-O-acetyl-2-bromo- or -chloro-2,3-dideoxy-D-glycero-beta-D-galacto-2-nonulopyranosonate (2, 3) with uridine, 5-fluorouridine, and cytidine under Koenigs-Knorr reaction conditions gave the corresponding (2 --> 5) linked disaccharide nucleoside derivatives, in yields of 32-47%. A similar reaction of 3 with inosine gave the (2 --> N1) linked derivative. These nucleoside analogues were converted into the final target compounds. The configuration at the anomeric position of these compounds was elucidated by means of proton and carbon nuclear magnetic resonance (H-1-, C-13-NMR) analysis, and consideration the rate of hydrolysis of the (2 --> 5) glycosidic linkage.