Koenigs-knorr glycosidations with 3,4,6-tri-O-acetyl-2-deoxy-2-[(4,4-dimethyl-2,6-dioxocyclohexylidenemethyl)-amino]-α-d-glucopyranosyl bromide

✍ Scribed by Antonio Gómez-Sánchez; María de Gracia García-Martín; Consolación Gasch

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 729 KB
• Volume: 164
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(87)80134-9

✦ Synopsis

The title compound (2), readily obtained as a fairly stable, crystalline solid from 2-amino-2-deoxy-D-glucose hydrochloride through its iv-protected derivative, 2-deoxy-2-[(4,4-dimethyl-2,6-dioxocyclohexylideneme~yl)amino]-~-glucopyranose, is an excellent donor of the 2-amino-2-deoxy-&D-glucopyranosyl group. The reaction of 2 with methyl, isopropyl, allyl, and cyclohexyl alcohols in the presence of Ag,CO, gave the methyl, isopropyl, allyl, and cyclohexyl B_glyc.osides 3-4 in 71-98% yields. Similar reaction with 1,2:3,4-di-O-isopropylidene-a-D-galactopyranose afforded (39%) the anticipated Plinked disaccharide O-[3,4,6-t&0acetyl-2-deoxy-2-[(4,4-dimethyl-2,6-dioxocyclohexylidenemethyl)amino] -P-Dglucopyranosyll-( 1+6)-l ,2: 3,4-di-0-isopropylidene-cY_D-galactopyranose (7). N-Deprotection of the glycosides 3-7 could be readily achieved by treatment with Cl,-CHCl, or by hydrolysis in the presence of Amberlite IRA-400 (HO-) resin, and the aminoglycosides, or their hydrochlorides, were obtained in very high yields. *Dedicated to Professor B. Helferich on the occasion of the 100th anniversary of his birth.