The N-acetyl GM 3 ganglioside (NAcGM 3 ) is an important glycosphingolipid currently used to prepare a new therapeutic cancer vaccine. Some quantities of this ganglioside were obtained by using [1→4] lactone as the trisaccharide protective function. Thus, sialylation of hexabenzyllactose acceptor with 5-acetyl neuraminylthiophenyl donor afforded the (2→ 3) trisaccharide as an α/β (3:1) mixture. The α-anomer was isolated through selective [1→4] lactone formation followed by chromatography. The lactone was hydrogenolyzed, per-O-acetylated, and selectively deacetylated, and a trichloroacetimidate donor was synthesized from the obtained compound. Azidosphingosine glycosylation, followed by azide group reduction and acylation of the resulting amino glycoside with stearic acid provided the protected ganglioside, which was finally subjected to the Zemplen's procedure, before saponification, to obtain the NAcGM 3 in an overall yield of 11.5% at multigram scale.

Gangliosides are membrane-associated glycosphingolipids. N-Acetyl GM3 and N-glycolyl GM3 are two tumor-associated antigens expressed in cancer tissues such as melanoma and mammalian cancer. In order to use these antigens in GM3-based vaccines for patients with early stage cancer, the synthetic version is recommended to avoid the risk of animal virus transmission from the source. However, the isolation of natural gangliosides is of comparative value for the structural characterization. The structures of N-acetyl and N-glycolyl GM3 extracted from dog and horse erythrocytes were evaluated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nuclear magnetic resonance techniques; additionally, the natural N-acetyl ganglioside was compared to a synthetic one. In addition to the main compound with C24:0 fatty acid chain, a minor component with an additional unsaturation in the ceramide chain was detected, in both the dog and the horse gangliosides. This paper shows spectroscopic evidence of the aforementioned compounds.