The synthesis and N.M.R. spectroscopy of derivatives of 6-amino-6-deoxy-D-galactose-6-15N

Derivatives of 6-amino-6-deoxy-D-galactose-6-¹⁵N have been synthesized by reaction of the 6-deoxy-6-iodo (1) or 6-O-p-tolylsulfonyl derivative of 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose with potassium phthalimide-¹⁵N. The reaction of 1 also yielded an elimination product, 6-deoxy-1,2:3,4-di-O-isopropylidene-β-L-arabino-hex-5-enopyranose. The structures of the 6-amino-6-deoxy-D-galactose derivatives and their precursors were characterized by proton- and ¹³C-n.m.r. spectroscopy, with confirmation of the ¹³C assignments by selective proton decoupling. Selective broadening of the C-1, C-4, C-5, and C-6 resonances of 6-amino-6-deoxy-1,2:3,4-di-O-isopropylidene-α-D-galactopyranose by low concentrations of cupric ion was observed, and studied by computerized measurements of the ¹³C linewidths. The application of this broadening to ¹³C-spectral assignments of amino sugar derivatives is indicated.     

Active, water-insoluble derivatives of D-glucose oxidase and alginic acid, chitin, and Celite

Treatment of 2-benzimidazolemethanol (4) with methanesulfonyl chloride and pyridine in chloroform afforded 2-(chloromethyl)-1-(methylsulfonyl)benzimidazole (6), which was also prepared by methanesulfonylation of 2-(chloromethyl)benzimidazole. Methanesulfonylation of α-(2-benzimidazolyl)benzyl alcohol (8) in chloroform yielded 2-(α-chlorobenzyl)-1-(methylsulfonyl)benzimidazole. 1-(Methylsulfonyl)-2-benzimidazolemethanol was obtained on methanesulfonylation of 4 pyridine at 0°, and α-[1-(methylsulfonyl)-2-benzimidazolyl]benzyl alcohol (12) was prepared from 8 by using the same reaction conditions. The reaction of 1-acetyl-2-(chloromethyl)-benzimidazole with silver methanesulfonate in benzene gave 1-acetyl-O-(methylsulfonyl)-2-benzimidazolemethanol. Compound 6 has some antitumor activity in the KB cell-culture system, and some antibacterial activity in the Staphylococcus aureus test-system; it is also active in preventing anaphylactic shock in a mouse test-system.     

Nitrous acid deamination of amino-oligosaccharide alditols and their per-O-methylated derivatives

Per-O-methylated amino-oligosaccharide alditols prepared from lacto-N-tetraose, lacto-N-fucopentaose I, and the mixed populations of oligosaccharide chains from α₁-acid glycoprotein and hog gastric mucin have been used as model substrates to assess the scope of the reaction sequence, N-deacetylation-nitrous acid deamination followed by derivatization, in the fragmentation of complex amino-oligosaccharides. G.l.c.-mass spectrometry has been used as the major tool in the characterization of products.     

The structure of d-threo-2,5-hexodiulosonic acid and derivatives in solution

The structure of d-threo-2,5-hexodiulosonic acid (1) and various derivatives in solution was determined by ¹³C-n.m.r. spectroscopy to be a hydrated, pyranose form. The structures of the methyl ester of 1 and of its 5-(dimethyl acetal) were confirmed by chemical means and by X-ray structure analysis.     

The behavior of some aldoses with 2,2-dimethoxypropane-N,N-dimethylformamide-p-toluenesulfonic acid. II. At 80 degrees

Four aldohexoses were individually subjected to the reagent mixture and temperature cited in the title; in each case, the 2,2-dimethoxypropane was present in only a small molar excess and the p-toluenesulfonic acid was used in trace amounts. D-Mannose (1) afforded the known 2,3:5,6-di-O-isopropylidene-D-mannofuranose (2) in significantly higher yield than when the reaction was conducted at room temperature. The other three aldoses, however, gave products markedly different from those formed under the milder conditions. 2-Acetamido-2-deoxy-D-mannose (3) gave a mixture of products from which methyl 2-acetamido-2-deoxy-2,3-N,O-isopropylidene-5,6-O-isopropylidene-α-D-mannofuranoside (4), 2-acetamido-2-deoxy-2,3-N,O-isopropylidene-5,6-O-isopropylidene-D-mannofuranose (5a), and methyl 2-acetamido-2-deoxy-5,6-O-isopropylidene-α-D-mannofuranoside (6a) were isolated. 2-Acetamido-2-deoxy-D-galactose (11) gave compounds identified as methyl 2-acetamido-2-deoxy-5,6-O-isopropylidene-β-D-galactofuranoside (12a) and methyl 2-acetamido-2-deoxy-4,6-O-isopropylidene-β-D-galactopyranoside (13a). 2-Acetamido-2-deoxy-D-glucose (16) afforded methyl 2-acetamido-2-deoxy-5,6-O-isopropylidene-β-D-glucofuranoside (17a) and methyl 2-acetamido-2-deoxy-4,6-O-isopropylidene-β-D-glucopyranoside (18a). Evidence in support of the structures assigned to these new derivatives is presented.     

1H- and 13C-n.m.r.-spectral study of synthetic methyl d-manno-oligosaccharides

¹H- and ¹³C-n.m.r. spectra for 16 synthetic methyl manno-oligosaccharides were recorded, and the signals for the anomeric protons and anomeric carbon atoms in branched manno-pentaosides and -hexaosides were assigned, based on the data for methyl manno-biosides and -triosides. These n.m.r. data identified the branching pattern of high-mannose types of glycans of glycopeptides with those of unambiguously synthesized manno-oligosaccharides, and confirmed the structures proposed for such glycans.     

Cleavage of the (1 goes to 3)-2-acetamido-2-deoxy-beta-D-glucopyranosyl linkage present in keratan sulfate. The A and B isoenzymes of human liver hexosaminidase (EC 3.2.1.30)

The disaccharide 2-acetamido-2-deoxy-beta-D-glucopyranosyl-(1 goes to 3)-D-[1-3H]-galactitol, prepared from keratan sulfate, was rapidly hydrolyzed by the A and B isoenzymes of normal human liver hexosaminidase (EC 3.2.1.30), and by the B isoenzyme prepared from the liver of a patient who had died of Tay-Sachs disease. The disaccharide substrate was also hydrolyzed by extracts of normal, cultured-skin fibroblasts, and fibroblasts of patients with Tay-Sachs disease, whereas it was not hydrolyzed by fibroblast extracts of patients with Sandhoff disease. Thus, effective degradation of keratan sulfate, secondary to a defect of the beta subunits present in the A and B isoenzymes of hexosaminidase, may contribute to the appearance of skeletal lesions in patients affected by Sandhoff disease.     

The application of 13C-n.m.r. spectroscopy to products derived from sucrose

Glycogen has been isolated from the livers of rats which had been fasted and then intubated with d-glucose. The structure of the glycogen, as determined by iodine staining and enzymic methods, was shown to be very similar to that from control animals. There were slight differences in the iodine-staining properties, but not as marked as that previously reported in the literature.     

Dioxolane and dioxane acetal derivatives of D-allose: Condensation of 3-O-benzyl-D-allose with acetaldehyde

Condensation of 3-O-benzyl-D-allose with acetaldehyde forms a complex mixture from which potentially useful mono- and di-O-ethylidene derivatives were isolated and identified. Compounds isolated and identified after conversion of unsubstituted hydroxyl groups into the corresponding acetates included 1,2-di-O-acetyl-3-O-benzyl-4,6-O-ethylidene-β-D-allopyranose; 5,6-di-O-acetyl-3-O-benzyl-1,2-O-(R)-ethylidene-α-D-allofuranose; and two 3-O-benzyl-1,2:5,6-di-O-ethylidene-α-D-allofuranoses, both having the R configuration in the 1,2-O-ethylidene ring. Furanose and pyranose conformations were determined by n.m.r. analysis, and the location and configuration of each acetal ring was established. The benzyl ether group in the furanose derivatives was removed by catalytic hydrogenation with subsequent formation of 3-O-acetyl analogs.     

Reactions of 3-(1-arylhydrazono-L-threo-2,3,4-trihydroxybutyl)-1-methyl-2-Quinoxalinones

The 1-methyl derivatives (3 and 4) of 3-(1-phenyl- (1) and 3-(1-p-bromophenylhydrazono-L-threo-2,3,4-trihydroxybutyl)-2-quinoxalinone (2) were prepared by methylation. Periodate oxidation of 3 gave 1-methyl-3-[1-(phenylhydrazono)glyoxal-1-yl]-2-quinoxalinone (5), which, on reduction with sodium borohydride, gave the corresponding 3-[2-hydroxy-1-(phenylhydrazono)ethyl] derivative (8). Reaction of 5 with hydroxylamine or benzoylhydrazine gave the corresponding 2-oxime (6) and 2-(benzoylhydrazone) (7), respectively. Acetic anhydride causes one molecule of 3 or 4 to undergo elimination of two molecules of water, with simultaneous acetylation and ring closure to afford pyrazoles 9 and 10, respectively. Pyrolysis of the triacetate of 3 led to the elimination of acetic acid from the sugar and the hydrazone residue, to give the 3-[5-(acetoxymethyl)-1-phenylpyrazol-3-yl] derivatives (9). Acetic acid was found to effect the same rearrangement, but without acetylation, of 1, 2, and 3 to give the 3-[5-(hydroxymethyl)] derivatives 11, 12, and 13, respectively. The structure of these pyrazoles was confirmed by a series of reactions, including methylation and acetylation. The n.m.r. and i.r. spectra of the compounds were investigated.     

Synthesis of a branched d-glucotetraose,the repeating unit of the extracellular polysaccharides of Grifola umbellate,Sclerotinia libertiana,Porodisculus pendulus,and Schizophyllum commune fries

The synthesis of d-glucotetraose, 3-O-[3-O-β-d-glucopyranosyl-β-d-glucopyranosyl]-6-O-β-d-glucopyranosyl-α (and β)-d-glucopyranose, the repeating unit of the extracellular polysaccharides of Grifora umbellata, Sclerotinia libertiana, Porodisculus pendulus, and Schizophyllum commune Fries, is described.