2-Acetamido-2-deoxy-0-glucopyranose

Amide derivatives have proved especially useful sugars for study by c.d. spectroscopy. The amide substituent is the same as the chromophore found in proteins, so that its optical properties have been extensively studied both experimentally and theoretically. 2-Acetamido sugars are found in many glycoproteins. The structure of 2-acetamido-2-deoxy-a-D-glucopyranose is given as an example in formula 7. 

Acetamido-2-deoxy-D-galactopyranose (—), and 2-Acetamido-2-deoxy-D-mannopyranose ( ) at Anomeric Equilibrium in Aqueous Solution (redrawn from Ref. 28), and 2-Acetamido-2-deoxy-D-glucopyranose (- -) at Anomeric Equilibrium in Aqueous Solution. (Redrawn from Ref. 29.)... 

Fig. 18.—The Circular Dichroism of a 2-Acetamido-2-deoxy-D-glucopyranose Film. (Redrawn from Ref. 37.)...

Ana,6s (2 AM6S (where I = a-L-iduronic acid, ANA6S = 2-acetamido-2-deoxy-a-D-glucopyranose 6-sulfate, G = / -D-glucuronic acid, and AMes = 2,5-anhydro-D-mannitol 6-sulfate, the last arising from 2-deoxy-... 

CieHss Ou 3 HaO 2-Acetamido-4-0-(2-acetamido-2-deoxy-J -D-glu-copyranosyl)-2-deoxy-/ -D-glucopyranose, trihydrate [N,N -diacetyl-/ -chitobiose, trihydrate] (BCHllT lO)94... 

Figure 7.34 Synthesis of 2-acetamido-2-deoxy-/3-D-galactopyranosyluronic acid-(l —> 4)-2-acetamido-2-deoxy-D-glucopyranose...

Warren and associates (18) have prepared a glycosyl azide derivative (15) of a heptasaccharide. This glycosyl azide was obtained from O-a-D-manno-pyranosyl-( 1 — 6)-0-[a-D-mannopyranosyl-( 1 — 3)-(9-a-D-mannopyrano syl-(l— 6)-0-a-D - mannopyranosyl - (1 — 3)] - O-fi- d - mannopyranosyl -(1 — 4) - O - (2 - acetamido - 2 - deoxy-/ -d-glucopyranosyl) - (1 — 4) - 2 -acetamido-2-deoxy-D-glucopyranose (12) by treatment of its peracetylated derivative 13 with trimethylsilyl trifuoromethanesulfonate, followed by reaction of the intermediary oxazoline 14 with trimethylsilyl azide. Reduction of the glycosyl azide 15 in the presence of Lindlar catalyst gave the glycosyla-mine derivative 16. The condensation of 16 with 1-tert-butyl N-(9-fluoren-... 

Zychlinski prepared 1 -amino-5-deoxy-5-acetamido-2,3,4-tri-6)-acetyl- 3-D-glucopyranose 60 by a synthesis of 11 steps. This amine component undergoes the U-4CRs very well and the products are cleavable by water, but unfortunately they are not very stable. 

Fig. 3. Proton-detected carbon-13 spin-lattice relaxation for the pentasaccharide p-trifluorao-acetamidophenyl-2,6-di-0-[/3-D-galactopyranosyl-(l 4)-0-2-acetamido-2-deoxy-/3-D-glu-copyranosyl]a-D-mannopyranoside. The measurements were performed with the two-dimensional method proposed by Skelton et al. [21], modified to obtain a one-dimensional pulse sequence. The figure shows the measurements for Cl in the 2-acetamido-2-deoxy-glucopyranose residue attached at position 2 on the mannopyranose residue.

The surprising feature of such a structure is the possibility of the occurrence of the /3-d anomer in the crystal. The electron density can be explained by the presence of 22% as the /3-d anomer it is indicated by the height of an unexplained peak near C-l at the correct distance and angle for the /3-D structure. When once-recrystallized 2-acetamido-2-deoxy-a-D-glucopyranose is dissolved, its initial rotation is [a]D +56.5°, as compared to +82° for the a-D and —21.5°... 

The most important result, however, is the binding of the trisaccharide tri-N-acetylchitotriose, as the model proposed for substrate binding and enzymic hydrolysis is based on this compound. The three substituted /3-D-glucopyranose residues are labeled A, B, and C in Fig. 2. Two observations are the same as for 2-acetamido-2-deoxy-D-glucose residue C has the same binding as the /3-d anomer, and the resulting shift of amino acid residue 62 (L-tryptophan) is 0.75 A. The hydrogen bonds between lysozyme and carbohydrates A and B are shown in Fig. 2 and listed in Table IV. Residue A, which is located... 

Compound 45, for example, gave l,l-bis(acetamido)-l-deoxy-octa-0-methylcellobiitol (50), which, by mild hydrolysis, gave 2,3,4,6-tetra-O-methyl-D-glucopyranose (51) and 2,3,5,6-tetra-O-methyl-D-gluco-furanose (52). 

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