SYNTHETIC ANTIGENS - SYNTHESIS OF 4-AMINOPHENYL O-ALPHA-D-MANNOPYRANOSYL-(1-]2)-O-ALPHA-D-MANNOPYRANOSYL-(1-]6)-O-ALPHA-D-MANNOPYRANOSIDE AND A RELATED DISACCHARIDE AND A TRISACCHARIDE

4-Nitrophenyl 2,3-O-isopropylidine-alpha-D-mannopyranoside 2 was condensed with O-(2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl)-(1 --> 2)-3,4,6-tri-O-acetyl-alpha-D-mannopyranosyl bromide 1 and 2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl bromide 11 in the presence of mercuric cyanide. Products were deprotected to yield, respectively, 4-nitrophenyl O-alpha-D-mannopyranosyl-(1 --> 2)-O-alpha-D-mannopyranosyl-(1 --> 6)-alpha-D-mannopyranoside 6 and 4-nitrophenyl O-alpha-D-mannopyranosyl-(1 --> 6)-alpha-D-mannopyranoside 14. The 4-nitrophenyl group of 6 was reduced to give title trisaccharide. Bromide 1 was also condensed with methyl 2,3,4-tri-O-benzyl-alpha-D-mannopyranoside 3 in the presence of silver trifluoromethanesulfonate and tetramethylurea to give protected trisaccharide derivative which was deprotected to furnish, methyl O-alpha-D-mannopyranosyl-(1 --> 2)-O-alpha-D-mannopyranosyl-(1 --> 6)-alpha-D-mannopyranoside 10. The identities of all protected and deprotected compounds were supported by H-1 and C-13 NMR spectral data.