2-DEOXY-2.3-DEHYDRO-SIALIC ACIDS .I. SYNTHESIS AND PROPERTIES OF 2-DEOXY-2.3-DEHYDRO-N-ACYL-NEURAMINIC ACIDS AND THEIR METHYL ESTERS

When 2-chloro-2-deoxy-4.7.8.9-tetra-O-acetyl-N-acetylneuraminic acid was treated with HCl-eliminating agents or when 2.4.7.8.9-penta-O-acetyl-N-acetylneuraminic acid was heated for several hours in dioxan solution and the reaction product was subsequently O-deacetylated, a compound was obtained which gave the resorcinol colour reaction characteristic of sialic acid derivatives. Its methyl ester upon catalytic hydrogenation took up 1 mole of hydrogen per mole and upon oxidation with sodium metaperiodate consumed 2 moles of the oxidant. These properties as well as the elementary analysis and the UV-, IR- and NMR-spectra of the new compound showed that it was 2-deoxy-2.3-dehydro-N-acetylneuraminic acid. The methyl esters of 2-deoxy-2.3-dehydro-N-glycolyl-, 2-deoxy-2.3-dehydro-N-propionyl-, 2-deoxy-2.3-dehydro-N-butyryl-, 2-deoxy-2.3-dehydro-N-benzoyl- and 2-deoxy-2.3-dehydro-N-carbobenzoxy-neuraminic acid were obtained by reactions analogous to those used for the preparation of the methyl ester of 2-deoxy-2.3-dehydro-N-acetylneuraminic acid. © 1969 Springer-Verlag.