SYNTHESIS OF A TREHALOSE HOMOLOG, 6-DEOXY-ALPHA-D-GLUCO-HEPTOPYRANOSYL 6-DEOXY-ALPHA-D-GLUCO-HEPTOPYRANOSIDE, AND THE CORRESPONDING BIS(HEPTOSIDURONIC ACID)

Crystalline 6-deoxy-α-d-gluco-heptopyranosyl 6-deoxy-α-d-gluco-heptopyranoside (8) and (6-deoxy- α-d-gluco-heptopyranosyluronic acid) 6-deoxy-α-d-gluco-heptopyranosiduronic acid (7) were synthesized from α,α-trehalose (1). Reaction of 2,3,4,2′,3′,4′-hexa-O-acetyl-6,6′-di-O-tosyl-α,α-trehalose with sodium dicarbonylcyclopentadienyliron, followed by oxidative hydrolysis or methanolysis, gave the 2,3,4,2′,3′,4′-hexa-acetate of 7 or its dimethyl ester, respectively. O-Deacetylation (Zemplén) then gave 7 and its dimethyl ester. Reduction of the hexa-O-acetyldicarboxylic acid with borane-oxolane complex yielded 8. Alternatively, cyanide displacement of hexa-O-acetyl-α,α-trehalose 6,6′-ditriflate gave the dinitrile hexaacetate of 7, which was O-deacetylated and then hydrolyzed with alkaline hydrogen peroxide to yield 7. 2,3,4,2′,3′,4′-Hexa-O-benzyl-α,α-trehalose 6,6′-ditriflate was similarly converted into the dinitrile, which was hydrolyzed to the corresponding diamide. Treatment of the 2,3,4,2′,3′,4′-hexa-O-acetyl-α,α-trehalosuronic acid 16 with thionyl chloride followed by diazomethane gave a crystalline bisdiazoketone which, however, failed to produce the expected bis(heptosiduronic acid) on attempted Wolff rearrangement. © 1990.