RESUMO
The 1-octyl, 1-pentadecyl, 1-hexadecyl, 1-heptadecyl, and 1-octadecyl diesters of (6-deoxy-alpha-D-gluco-heptopyranosyluronic acid) 6-deoxy-alpha-D-gluco-heptopyranosiduronic acid, a new homolog of trehalosuronic acid, were prepared by two procedures. One procedure involved conversion of the peracetylated acid into its dichloride, reaction of the latter with the alkanols, and acid-catalyzed deacetylation of the products, whereas the other consisted of reaction of alkyl mesylates with the potassium salt of the unprotected acid.
Assuntos
Fatores Corda/síntese química , Configuração de Carboidratos , Sequência de Carboidratos , Fatores Corda/química , Dados de Sequência MolecularRESUMO
Crystalline 6-deoxy-alpha-D-gluco-heptopyranosyl 6-deoxy-alpha-D-gluco- heptopyranoside (8) and (6-deoxy-alpha-D-gluco-heptopyranosyluronic acid) 6-deoxy-alpha-D-gluco-heptopyranosiduronic acid (7) were synthesized from alpha, alpha-trehalose (1). Reaction of 2,3,4,2',3',4'-hexa-O-acetyl- 6,6'-di-O-tosyl-alpha, alpha-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-alpha, alpha-trehalose 6,6'-ditriflate gave the dinitrile hexa-acetate 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-alpha, alpha-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-alpha, alpha-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.