Benzyl 2-azido-2-deoxy-β-d-galactopyranoside was converted into benzyl 2-azido-4,6-O-benzyl-2-deoxy-β-d-galactopyranoside via benzylidenation, p-methoxybenzylation, acid hydrolysis, benzylation, and selective oxidation. Condensation of 1,2,3,4,6-penta-O-acetyl-β-d-galactopyranose with benzyl 2-azido-4,6-di-O-benzyl-2-deoxy- β-d-galactopyranoside in the presence of trimethylsilyl triflate gave crystalline benzyl 2-azido-4,6-di-O-benzyl-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl-β-d-gal actopyranosyl)-β-d-galactopyranoside (76%), which was converted into benzyl 2-azido-4,6-di-O-benzyl-2-deoxy-3-O-(2,6-di-O-benzyl-β-d-galactopyr anosyl)-β-d-galactopyranoside and condensed with 3,4,6-tri-O-acetyl-2-azido-2-deoxy-α-d-galactopyranosyl bromide in the presence of silver silicate on alumina and molecular sieve 4 Å to give 61% of benzyl O-(3,4,6-tri-O-acetyl-2-azido-2-deoxy-β-d-galactopyranosyl)- (1→4)-O-(2,6-di-O-benzyl-β-d-galactopyranosyl)-(1→3)-2- azido-4,6-di-O-benzyl-2-deoxy-β-d-galactopyranoside. Reduction with sodium borohydride followed by N-acetylation, O-deacetylation, and catalytic hydrogenolysis then gave O-(2-acetamido-2-deoxy-β-d-galactopyranosyl)-(1→4)-O-β-d- galactopyranosyl-(1→3)-2-acetamido-2-deoxy-d-galactopyranose, the desialylated human Cad-antigenic determinant. © 1986.
CHEMICAL SYNTHESIS OF THE DESIALYLATED HUMAN CAD-ANTIGENIC DETERMINANT
MARRA, Alberto;
1986
Abstract
Benzyl 2-azido-2-deoxy-β-d-galactopyranoside was converted into benzyl 2-azido-4,6-O-benzyl-2-deoxy-β-d-galactopyranoside via benzylidenation, p-methoxybenzylation, acid hydrolysis, benzylation, and selective oxidation. Condensation of 1,2,3,4,6-penta-O-acetyl-β-d-galactopyranose with benzyl 2-azido-4,6-di-O-benzyl-2-deoxy- β-d-galactopyranoside in the presence of trimethylsilyl triflate gave crystalline benzyl 2-azido-4,6-di-O-benzyl-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl-β-d-gal actopyranosyl)-β-d-galactopyranoside (76%), which was converted into benzyl 2-azido-4,6-di-O-benzyl-2-deoxy-3-O-(2,6-di-O-benzyl-β-d-galactopyr anosyl)-β-d-galactopyranoside and condensed with 3,4,6-tri-O-acetyl-2-azido-2-deoxy-α-d-galactopyranosyl bromide in the presence of silver silicate on alumina and molecular sieve 4 Å to give 61% of benzyl O-(3,4,6-tri-O-acetyl-2-azido-2-deoxy-β-d-galactopyranosyl)- (1→4)-O-(2,6-di-O-benzyl-β-d-galactopyranosyl)-(1→3)-2- azido-4,6-di-O-benzyl-2-deoxy-β-d-galactopyranoside. Reduction with sodium borohydride followed by N-acetylation, O-deacetylation, and catalytic hydrogenolysis then gave O-(2-acetamido-2-deoxy-β-d-galactopyranosyl)-(1→4)-O-β-d- galactopyranosyl-(1→3)-2-acetamido-2-deoxy-d-galactopyranose, the desialylated human Cad-antigenic determinant. © 1986.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
