Condensation of crystalline methyl 2-azido-4,6-O-benzylidene-2-deoxy-β-d-galactopyranoside with methyl (2,3,4-tri-O-acetyl-α-l-idopyranosyl bromide)-uronate in dichloromethane, in the presence of silver triflate and molecular sieve, provided 54% of methyl 2-azido-4,6-O-benzylidene-2-deoxy-3-O-(methyl 2,3,4,-tri-O-acetyl-α-l-idopyranosyluronate)-β-d- galactopyranoside. The use of methyl (2,3,4-tri-O-acetyl-α-l-idopyranosyl trichloroacetimidate)uronate as glycosyl donor, in the presence of trimethylsilyl triflate, improved the yield to 68%. Regio-selective opening of the benzylidene group with sodium cyanoborohydride followed successively by O-sulfation with the sulfur trioxide-trimethylamine complex, saponification, catalytic hydrogenolysis and selective N-acetylation gave the di-sodium salt of methyl 2-acetamido-2-deoxy-3-O-(α-l-idopyranosyluronic acid)-4-O-sulfo-β-d-galactopyranoside. Condensation of methyl 2-azido-4,6-O-benzylidene-2-deoxy-β-d-galactopyranoside with methyl (2,3,4-tri-O-acetyl-α-d-glucopyranosyl bromide)uronate in dichloromethane, in the presence of silver triflate and molecular sieve, gave methyl 2-azido-4,6-O-benzylidene-2-deoxy-3-O-(methyl 2,3,4-tri-O-acetyl-β-d-glucopyranosyluronate)-β-d-galactopyran oside in 85% yield. The sequence already described then gave the disodium salt of methyl 2-acetamido-2-deoxy-3-O-(β-d-glucopyranosyluronic acid)-4-O-sulfo-β-d-galactopyranoside. © 1989.
SYNTHESIS OF DISACCHARIDE FRAGMENTS OF DERMATAN SULFATE
MARRA, Alberto;
1989
Abstract
Condensation of crystalline methyl 2-azido-4,6-O-benzylidene-2-deoxy-β-d-galactopyranoside with methyl (2,3,4-tri-O-acetyl-α-l-idopyranosyl bromide)-uronate in dichloromethane, in the presence of silver triflate and molecular sieve, provided 54% of methyl 2-azido-4,6-O-benzylidene-2-deoxy-3-O-(methyl 2,3,4,-tri-O-acetyl-α-l-idopyranosyluronate)-β-d- galactopyranoside. The use of methyl (2,3,4-tri-O-acetyl-α-l-idopyranosyl trichloroacetimidate)uronate as glycosyl donor, in the presence of trimethylsilyl triflate, improved the yield to 68%. Regio-selective opening of the benzylidene group with sodium cyanoborohydride followed successively by O-sulfation with the sulfur trioxide-trimethylamine complex, saponification, catalytic hydrogenolysis and selective N-acetylation gave the di-sodium salt of methyl 2-acetamido-2-deoxy-3-O-(α-l-idopyranosyluronic acid)-4-O-sulfo-β-d-galactopyranoside. Condensation of methyl 2-azido-4,6-O-benzylidene-2-deoxy-β-d-galactopyranoside with methyl (2,3,4-tri-O-acetyl-α-d-glucopyranosyl bromide)uronate in dichloromethane, in the presence of silver triflate and molecular sieve, gave methyl 2-azido-4,6-O-benzylidene-2-deoxy-3-O-(methyl 2,3,4-tri-O-acetyl-β-d-glucopyranosyluronate)-β-d-galactopyran oside in 85% yield. The sequence already described then gave the disodium salt of methyl 2-acetamido-2-deoxy-3-O-(β-d-glucopyranosyluronic acid)-4-O-sulfo-β-d-galactopyranoside. © 1989.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
