The synthesis of a carbohydrate-like dihydrooxazine and tetrahydrooxazine as putative inhibitors of glycoside hydrolases: A direct synthesis of isofagomine

2002 ◽  
Vol 80 (8) ◽  
pp. 857-865 ◽  
Author(s):  
Wayne M Best ◽  
James M Macdonald ◽  
Brian W Skelton ◽  
Robert V Stick ◽  
D Matthew G Tilbrook ◽  
...  
Keyword(s):  
Direct Synthesis ◽  
Glycoside Hydrolases ◽  
Crystalline Solid ◽  
Glycosidase Inhibitors ◽  
Protecting Group ◽  
Mild Acid Hydrolysis ◽  
Catalytic Hydrogenolysis ◽  
Palladium On Carbon ◽  
Mild Acid

The treatment of benzyl 2,3-O-isopropylidene-β-L-xylopyranoside with N-hydroxyphthalimide under Mitsunobu conditions, followed by protecting-group interchange, gave benzyl 4-O-[(tert-butoxycarbonyl)amino]-2,3- O-isopropylidene-α-D-arabinoside. Mild acid hydrolysis and catalytic hydrogenolysis afforded 4-O-[(tert-butoxycarbonyl)amino]-D-arabinose that, upon heating in water, gave the dihydrooxazine [(4R,5S,6R)-5,6-dihydro-4,5-dihydroxy-6-hydroxymethyl-4H-1,2-oxazine] as a crystalline solid. A single-crystal structure determination of this solid showed it to exist in the 5H6 conformation. Reduction of the dihydrooxazine gave the tetrahydrooxazine [(4R,5S,6R)-4,5-dihydroxy-6-hydroxymethyl-3,4,5,6-tetrahydro-2H-1,2-oxazine]. The dihydrooxazine was an effective inhibitor of two β-glucosidases (Ki = 27 and 35 µM). Benzyl 2,3-O-isopropylidene-β-L-xylopyranoside, via the derived imidazylate, was converted into a nitrile that, upon reduction and protecting-group manipulations, gave benzyl 4-C-aminomethyl-4-deoxy-α-D-arabinoside. Treatment of this amine with hydrogen and palladium-on-carbon gave isofagomine.Key words: dihydrooxazine, tetrahydrooxazine, isofagomine, iminosugars, glycosidase inhibitors.

INVESTIGATIONS ON RUBBER-BEARING PLANTS: II. CARBOHYDRATES IN THE ROOTS OF TARAXACUM KOK-SAGHYZ ROD.

1946 ◽  
Vol 24c (2) ◽  
pp. 47-53 ◽  
Author(s):  
Paul R. Gorham
Keyword(s):  
Reducing Sugars ◽  
Analytical Data ◽  
Dry Weight ◽  
Hot Water ◽  
Soluble Carbohydrates ◽  
Mild Acid Hydrolysis ◽  
Rubber Bearing ◽  
One Year ◽  
Mild Acid

The soluble carbohydrates were extracted, by means of hot water, from dried ground roots of Taraxacum kok-saghyz Rod. that had been extracted previously with acetone and benzene. A cleared portion of the extract served for the determination of hexose and, after invertase hydrolysis, sucrose. Another portion was subjected to mild acid hydrolysis before clearing, and served for the determination of total reducing value, whence fructosans, as inulin, were calculated. Separation of the free reducing sugars and sucrose from the fructosans by ethanol extraction proved unsatisfactory. Analyses of 171 one-year old roots from six crosses gave the following average values expressed as per cent dry weight: hexose 1.6, sucrose 4.7, and inulin 41. The analytical data suggest the possibility of selecting and breeding for strains of kok-saghyz capable of high carbohydrate production.

POLYGLYCERYLPHOSPHORIC ACIDS: I. SYNTHESIS OF BIS(L-α-GLYCERYL) PHOSPHORIC ACID

1958 ◽  
Vol 36 (2) ◽  
pp. 243-248 ◽  
Author(s):  
Erich Baer ◽  
Dmytro Buchnea
Keyword(s):  
Phosphoric Acid ◽  
Acid Hydrolysis ◽  
Intermediate Product ◽  
Phenyl Ester ◽  
Mild Acid Hydrolysis ◽  
Protective Groups ◽  
Catalytic Hydrogenolysis ◽  
Mild Acid

Bis(L-α-glyceryl) phosphoric acid has been prepared by synthesis. It was obtained by phosphorylating D-acetone glycerol with phenylphosphoryl dichloride in the presence of pyridine, and freeing the intermediate product, bis(acetone L-α-glyceryl) phosphoric acid phenyl ester, of its protective groups by catalytic hydrogenolysis and mild acid hydrolysis.

SYNTHESIS OF PHOSPHOLIPID METABOLITES: L-α-GLYCERYLPHOSPHORYL-2-AMINO-2-METHYLPROPANOL

1964 ◽  
Vol 42 (11) ◽  
pp. 1547-1551 ◽  
Author(s):  
Erich Baer ◽  
G. Venkat Rao
Keyword(s):  
Fatty Acid ◽  
Acid Hydrolysis ◽  
Phosphorus Oxychloride ◽  
Barium Salt ◽  
Mild Acid Hydrolysis ◽  
Acid Dichloride ◽  
Catalytic Hydrogenolysis ◽  
Mild Acid

A constituent of and possible intermediate in the metabolism of phosphatidyl-2-amino-2-methylpropanols has been synthesized. The fatty-acid-free moiety, i.e. L-α-glycerylphosphoryl-2-amino-2-methylpropanol, was obtained by phosphorylating D-acetone glycerol with phosphorus oxychloride and quinoline, esterifying the acetone L-α-glycerylphosphoric acid dichloride with N-carbobenzoxy-2-amino-2-methylpropanol in the presence of pyridine, removing the acetone group of acetone L-α-glycerylphosphoryl-N-carbobenzoxy-2-amino-2-methylpropanol by mild acid hydrolysis, and freeing the barium salt of L-α-glycerylphosphoryl-N-carbobenzoxy-2-amino-2-methylpropanol from its protective carbobenzoxy group by catalytic hydrogenolysis.

Phosphonolipids. XXIV. Phosphonolipid metabolites. Synthesis of L-α-glyceryl-(N-methyl-2-aminoethyl)phosphonate

1970 ◽  
Vol 48 (9) ◽  
pp. 988-990 ◽  
Author(s):  
Erich Baer ◽  
Sripada K. Pavanaram
Keyword(s):  
Acid Hydrolysis ◽  
Phosphonic Acid ◽  
Mild Acid Hydrolysis ◽  
Catalytic Hydrogenolysis ◽  
Mild Acid

The synthesis of L-α-glyceryl-(N-methyl-2-aminoethyl)phosphonate, a possible intermediate in the biosynthesis and metabolism of L-α-phosphono(N-methyl)cephalins, is described. It was obtained by phosphonylating D-acetone glycerol with (N-carbobenzoxy,N-methyl-2-aminoethyl)phosphonic acid monochloride and triethylamine, and removing the protective isopropylidene and carbobenzoxy groups by mild acid hydrolysis and catalytic hydrogenolysis, respectively.

POLYGLYCERYLPHOSPHORIC ACIDS: I. SYNTHESIS OF BIS(L-α-GLYCERYL) PHOSPHORIC ACID

1958 ◽  
Vol 36 (1) ◽  
pp. 243-248 ◽  
Author(s):  
Erich Baer ◽  
Dmytro Buchnea
Keyword(s):  
Phosphoric Acid ◽  
Acid Hydrolysis ◽  
Intermediate Product ◽  
Phenyl Ester ◽  
Mild Acid Hydrolysis ◽  
Protective Groups ◽  
Catalytic Hydrogenolysis ◽  
Mild Acid

Bis(L-α-glyceryl) phosphoric acid has been prepared by synthesis. It was obtained by phosphorylating D-acetone glycerol with phenylphosphoryl dichloride in the presence of pyridine, and freeing the intermediate product, bis(acetone L-α-glyceryl) phosphoric acid phenyl ester, of its protective groups by catalytic hydrogenolysis and mild acid hydrolysis.

Amino acid sequence of cyanogen bromide fragment CB5 of human hemopexin

1989 ◽  
Vol 54 (3) ◽  
pp. 803-810 ◽  
Author(s):  
Ivan Kluh ◽  
Ladislav Morávek ◽  
Manfred Pavlík
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Acid Hydrolysis ◽  
Cyanogen Bromide ◽  
Polypeptide Chain ◽  
Amino Acid Residues ◽  
Mild Acid Hydrolysis ◽  
Methionine Residue ◽  
Cyanogen Bromide Fragment ◽  
Mild Acid

Cyanogen bromide fragment CB5 represents the region of the polypeptide chain of hemopexin between the fourth and fifth methionine residue (residues 232-352). It contains 120 amino acid residues in the following sequence: Arg-Cys-Ser-Pro-His-Leu-Val-Leu-Ser-Ala-Leu-Thr-Ser-Asp-Asn-His-Gly-Ala-Thr-Tyr-Ala-Phe-Ser-Gly-Thr-His-Tyr-Trp-Arg-Leu-Asp-Thr-Ser-Arg-Asp-Gly-Trp-His-Ser-Trp-Pro-Ile-Ala-His-Gln-Trp-Pro-Gln-Gly-Pro-Ser-Ala-Val-Asp-Ala-Ala-Phe-Ser-Trp-Glu-Glu-Lys-Leu-Tyr-Leu-Val-Gln-Gly-Thr-Gln-Val-Tyr-Val-Phe-Leu-Thr-Lys-Gly-Gly-Tyr-Thr-Leu-Val-Ser-Gly-Tyr-Pro-Lys-Arg-Leu-Glu-Lys-Glu-Val-Gly-Thr-Pro-His-Gly-Ile-Ile-Leu-Asp-Ser-Val-Asp-Ala-Ala-Phe-Ile-Cys-Pro-Gly-Ser-Ser-Arg-Leu-His-Ile-Met. The sequence was derived from the data on peptides prepared by cleavage of fragment CB5 by mild acid hydrolysis, by trypsin and chymotrypsin.

scholarly journals A New Look at the Enterobacterial Common Antigen Forms Obtained during Rough Lipopolysaccharides Purification

2021 ◽  
Vol 22 (2) ◽  
pp. 701
Author(s):  
Tomasz K Gozdziewicz ◽  
Anna Maciejewska ◽  
Alona Tsybulska ◽  
Czeslaw Lugowski ◽  
Jolanta Lukasiewicz
Keyword(s):  
Current Knowledge ◽  
Membrane Integrity ◽  
Gel Filtration ◽  
Common Antigen ◽  
Mild Acid Hydrolysis ◽  
Enterobacterial Common Antigen ◽  
Lipopolysaccharide Endotoxin ◽  
Lipid Moiety ◽  
Detailed Composition ◽  
Mild Acid

Enterobacterial common antigen (ECA) is a conserved antigen expressed by enterobacteria. It is built by trisaccharide repeating units: →3)-α-D-Fucp4NAc-(1→4)-β-D-ManpNAcA-(1→4)-α-D-GlcpNAc-(1→ and occurs in three forms: as surface-bound linear polysaccharides linked to a phosphoglyceride (ECAPG) or lipopolysaccharide − endotoxin (ECALPS), and cyclic form (ECACYC). ECA maintains, outer membrane integrity, immunogenicity, and viability of enterobacteria. A supernatant obtained after LPS ultracentrifugation was reported as a source for ECA isolation, but it has never been assessed for detailed composition besides ECACYC. We used mild acid hydrolysis and gel filtration, or zwitterionic-hydrophilic interaction liquid (ZIC®HILIC) chromatography combined with mass spectrometry for purification, fractionation, and structural analysis of rough Shigella sonnei and Escherichia coli R1 and K12 crude LPS preparations. Presented work is the first report concerning complex characteristic of all ECA forms present in LPS-derived supernatants. We demonstrated high heterogeneity of the supernatant-derived ECA that contaminate LPS purified by ultracentrifugation. Not only previously reported O-acetylated tetrameric, pentameric, and hexameric ECACYC have been identified, but also devoid of lipid moiety linear ECA built from 7 to 11 repeating units. Described results were common for all selected strains. The origin of linear ECA is discussed against the current knowledge about ECAPG and ECALPS.

Pigments of marine animals. XI. Angular naphthopyrones from the crinoid Comanthus parvicirrus timorensis

1971 ◽  
Vol 24 (7) ◽  
pp. 1487 ◽  
Author(s):  
IR Smith ◽  
MD Sutherland
Keyword(s):  
Methyl Ether ◽  
Dry Weight ◽  
Water Soluble ◽  
Spectral Studies ◽  
Mild Acid Hydrolysis ◽  
Marine Animals ◽  
Yellow Colour ◽  
Methoxy Derivative ◽  
Colour Variant ◽  
Mild Acid

Green specimens of the comatulid crinoid, Comanthus parvicirrus timorensis J. Muller, yield to acetone three yellow water-soluble colouring matters, comaparvin sulphate, 6-methoxycomaparvin sulphate, and 6-methoxycomaparvin 5-methyl ether sulphate in approximately 0.1 %, 0.7 %, and 0.7 % yield respectively of the dry weight of the animal, Mild acid hydrolysis yields the corresponding phenols, the structures of which have been deduced largely by spectral studies as very probably 5,8-dihydroxy-10-methoxy-2-n-propyl-4H-naphtho[1,2-b]pyran-4-one (1), the 6-methoxy derivative of (1), and the 6-methoxy methyl ether of (1) respectively. A yellow colour variant of the same species yielded the same colouring matters in slightly different proportions. The calcareous skeleton contains what are probably polyhydroxynaphthoquinones in combined form.

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