Patent ID: 8822659

Claim:
A method of preparation of at least one pentasaccharide starting from a protected precursor of the formula (1): wherein: R 1 is a branched, linear, or cyclic alkyl group (C 1 -C 20 ); R 2 is independently azide or an amine protected by a carbamate group, in which at least one of the R 2 is an azide and at least one of the R 2 is an amine protected by a carbamate group; R 3 is a branched or linear aliphatic acyl group or a substituted or unsubstituted aromatic acyl; R 4 is a substituted or unsubstituted benzyl group; R 5 is a branched, linear, or cyclic alkyl group (C 1 -C 20 ) or any substituted or unsubstituted aryl group; the process comprising, in order: i) saponifying the ester and methoxycarbonyl groups of the protected precursor compound by reacting the precursor compound with concentrated NaOH, giving rise to a compound of formula (2): ii) O-sulfating free hydroxyls of the compound of formula (2) by reacting the compound of formula (2) with sulphur trioxide-trimethylamine complex, giving rise to a compound of formula (3): iii) selectively reducing the azide groups of the compound of formula (3) by reacting the compound of formula (3) with P(CH 3 ) 3 , giving rise to a compound of formula (4): wherein R 6 is independently NH 2 or an amine protected by a carbamate group, and at least one R 6 is an amine protected by a carbamate group; iv) hydrogenating benzyl groups of the compound of formula (4) by reacting the compound of formula (4) in the presence of hydrogen with Pd(OH) 2 on carbon/20% by weight of Pd, giving rise to a compound of formula (5): v) N-sulfating amines of the compound of formula (5) by reacting the compound of formula (5) with sulphur trioxide-pyridine complex, giving rise to a compound of formula (6):