Glucosamine derivatives

Henry reaction of the (V-acetyl-D-glucosamine derived nitrosugar 1 with 2,3-O-cyclohexylidene-D-glyceraldehyde (2) furnishes a single product 3 in 85-90% yield7. 

Observations on the Acidic Hydrolysis of Some D-Glucosamine Derivatives," A. B. Foster, D. Horton, and M. Stacey, Chem. Ind. (London)., (1956) 175-176. 

Scheme 3.47 D-Glucosamine-derived a-hydroxy sulfonamide ligand for additions of ZnEt2 to aldehydes.

Hexosamine mit stickstoffhaltigen Substituenten. Glucosaminyl-azide (l-Azido-glucosamin-Derivate). A. Bertho und A. Revesz (23) haben a-l-Brom-3.4.6-triacetyl-D-glucosamin-hydrobromid mit Silber-azid umgesetzt. Das (als freie Base erhaltene) 1 -/ -Azido-3-4.6-triacetyl-... 

In a study of the oxidation of 2-amino-2-deoxy-D-glucose (D-glucosamine) derivatives, Neuberger12 obtained better results using sodium metaperiodate (at its accompanying pH of 3 to 4) than with periodic acid at lower pH values and a pH of 4.5 was found by Jeanloz and Forchielli78a to be optimal for these derivatives. 

Tungsten aryloxo complexes have been shown to catalyze the intramolecular metathesis reactions of di- and tri-substituted co-unsaturated glucose and glucosamine derivatives to yield bicyclic carbohydrate-based compounds containing 12- and 14-membered rings [108,214,215]. An example is shown in Eq. 37. The tolerance for amides and esters is noteworthy, as are the yields and the size of the rings that are formed. 

Figure 6.59 Structural modifications of glucosamine-derived urea catalysts screening in the formation of Strecker adduct 12 (Scheme 6.174).

Vasella has applied the concept of anomeric anion stabilization by a nitro group to the /3-D-JV-acetyl-D-glucosamine derivative 177, available in four steps from N-acetyl-n-glucosamine [52] (Scheme 39). Reaction of the tetraethylammonium nitronate derived from 177 with aldehyde 178 provides anti-179 which then undergoes stereoselectively reduction (see Sect. 2.2.1) to provide -C-glycoside 180, intermediate in a synthesis of N-acetyl-neuraminic acid. 

The phenylthionocarbonate procedure was also used for the cyclization of a 5-oxime-ether radical (Scheme 6) [17]. The stereochemical outcome of this reaction is almost identical with that observed for a closely related 6-methoxyhex-5-enyl radical cyclization [12,14]. A related glucosamine-derived radical cyclization has been employed for the synthesis of allosamizoline 13 [18]. Other examples in this area include the cyclization of... 

The complex 12 catalyses the RCM of di- and tri-substituted >-unsaturated protected glucose and glucosamine derivatives yielding bicyclic carbohydrate-based compounds containing 12- and 14-atom rings230. 

In model reactions employing a glucosamine-derived anomeric phosphate, we found that we were able to monitor the appearance of the phosphoroimidazolidate intermediate by mass spectrometry. Similarly, we were able to monitor its disappearance upon slow addition of a famesyl monophosphate salt added via syringe. 

Both anomers of 2-acetamido-2-deoxy-D-glucopyranosyl phosphate have been prepared previously however, the methods used are not easily adapted to obtain glucosamine derivatives carrying 3-hydroxytetradecanoic acid attached to the amino group. 

Since the synthesis of glycolipids involves the synthesis of both the lipid and the oligosaccharide portions, we shall also discuss that part of the recorded lipid synthetic work which has involved the use of carbohydrates. In fact, some of the first-recorded applications of carbohydrate molecules as chiral templates are to be found in the lipid field particularly with the use of 1,2 5,6-di-O-isopropylidene-D-mannitol [33] as a precursor of chiral glycerol derivatives for the synthesis of phospholipids and glycolipids based on glycerol and with the use of glucosamine derivatives for the synthesis of phytosphingosines [34] and since this area has not previously been reviewed, it will be treated with a more historical perspective. 

Thus, the O-benzylated glucosamine derivative 60 was condensed with the spacer-linked L-rhamnoside 61, followed by the removal of the base-labile protecting group at the site of the chain extension to afford the disaccharide acceptor 62. The trisaccharide block 67 was prepared in a similar approach. Thus, condensation of the glucosamine derivative 63 with rhamnoside 64 afforded the disaccharide... 

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