172471-79-3

Upstream product

• 115196-83-3 methyl 4-azido-3-O-benzyl-4,6-dideoxy-α-D-mannopyranoside 
• 182273-55-8 4-azido-2-O-benzoyl-3-O-benzyl-4,6-dideoxy-α-D-mannopyranosyl chloride 
• 2916-68-9 2-(Trimethylsilyl)ethanol 
• 182273-57-0 2-(trimethylsilyl)ethyl 4-azido-2-O-benzoyl-3-O-benzyl-4,6-dideoxy-α-D-mannopyranoside 

Downstream Products

• 172471-69-1 Acetic acid (2R,3S,4S,5R,6R)-5-azido-2-[(2S,3S,4S,5R,6R)-5-azido-4-benzyloxy-6-methyl-2-(2-trimethylsilanyl-ethoxy)-tetrahydro-pyran-3-yloxy]-4-benzyloxy-6-methyl-tetrahydro-pyran-3-yl ester 
• 182273-60-5 (2R,3S,4S,5R,6R)-5-Amino-2-[(2S,3S,4S,5R,6R)-5-amino-4-benzyloxy-6-methyl-2-(2-trimethylsilanyl-ethoxy)-tetrahydro-pyran-3-yloxy]-4-benzyloxy-6-methyl-tetrahydro-pyran-3-ol 
• 172471-71-5 2-(trimethylsilyl)ethyl 4-azido-3-O-benzyl-4,6-dideoxy-α-D-mannopyranosyl-(1→2)-4-azido-3-O-benzyl-4,6-dideoxy-α-D-mannopyranoside 
• 182273-61-6 C₅₃H₇₂N₂O₁₃Si 

Relevant academic research and scientific papers

Towards the complete synthetic O-Antigen of: Vibrio cholerae O1, serotype inaba: Improved synthesis of the conjugation-ready upstream terminal hexasaccharide determinant

Synthesis of the upstream terminal hexasaccharide part of the lipopolysaccharides (LPS) of Vibrio cholerae O1, serotype Inaba has been improved. The key improvements include but are not limited to optimized conditions for the stereoselectivity of glycosylation reactions involved and fewer number of synthetic steps, compared to previous approaches. Particularly noteworthy is conducting the glycosylation of the very reactive glycosyl acceptor 8-Azido-3,6-dioxaoctanol with the fully assembled hexasaccharide trichloroacetimidate under thermodynamic control. It produced the desired α glycoside with an α:β ratio of 7:1, compared with the ratio of 1.1:1, observed when the coupling was conducted conventionally. Several substances, which were previously obtained in purity acceptable only for synthetic intermediates, were now obtained in the analytically pure state and were fully characterized. The structure of the key trisaccharide glycosyl acceptor was confirmed by single-crystal X-ray structure determination.

Synthesis of four glycosides of a disaccharide fragment representing the terminus of the O-polysaccharide of Vibrio cholerae O:1, serotype Inaba, bearing aglycons suitable for linking to proteins

Methyl 4-azido-3-O-benzyl-4,6-dideoxy-α-D-mannopyranoside was converted into the crystalline 2-(trimethylsilyl)ethyl 4-azido-2-O-benzoyl-3-O-benzyl-4,6-dideoxy-α-D-mannopyranoside. Debenzoylation of the latter, followed by glycosylation of the resulting 2-hydroxy derivative with 2-O-acetyl-4-azido-4,6-dideoxy-α-D-mannopyranosyl chloride, gave the 2-(trimethylsilyl)ethyl glycoside of the corresponding disaccharide (8). Deacetylation of 8, followed by reduction of the resulting 4-azido-2-hydroxy derivative with H2S, gave the corresponding amine 10. The latter was treated with 4-O-benzyl-3-deoxy-L-glycero-tetronic acid to give, after debenzylation and acetylation, the fully protected 2-(trimethylsilyl)ethyl α-glycoside of the disaccharide fragment of the O-PS of Vibrio cholerae O:1, serotype Inaba (13). Compound 13 was transformed into the corresponding 1-trichloroacetimidate which was treated, separately, with methyl 6-hydroxyhexanoate and 2-(2-methoxycarbonylethylthio)ethanol, to give two analogs of 13 possessing a differing linkage arm, namely the methyl esters 16 and 17. Each of 16 and 17 was treated with aqueous sodium hydroxide, followed by a cation-exchange resin, to give the two corresponding carboxylic acids (19 and 22). Alternately, treatment of 16 and 17 with hydrazine hydrate gave the acid hydrazides 20 and 23.