A Stereospecific Synthesis of L-Desosamine

1974 ◽  
Vol 52 (1) ◽  
pp. 122-124 ◽  
Author(s):  
Hans H. Baer ◽  
Chung-Wai Chiu
Keyword(s):  
Acid Hydrolysis ◽  
Nitro Group ◽  
Catalytic Hydrogenation ◽  
Glycosidic Bond ◽  
Stereospecific Synthesis ◽  
Borohydride Reduction ◽  
Amino Glycoside ◽  
Hydrolysis Of

L-Desosamine (3,4,6-trideoxy-3-dimethylamino-L-xylo-hexose), the enantiomer of a widely distributed antibiotics component, was synthesized by borohydride reduction of methyl 3,4,6-trideoxy-3-nitro-α-L-erythro-hex-3-enopyranoside followed by catalytic hydrogenation of the nitro group, N,N-dimethylation of the resulting saturated amino glycoside, and acid hydrolysis of the glycosidic bond.

Synthesis of 4-deoxydaunosamine and 4-deoxyristosamine

1980 ◽  
Vol 58 (16) ◽  
pp. 1751-1758 ◽  
Author(s):  
Hans H. Baer ◽  
Hanna R. Hanna
Keyword(s):  
Acetic Acid ◽  
Acid Hydrolysis ◽  
Sodium Borohydride ◽  
Catalytic Hydrogenation ◽  
Sodium Acetate ◽  
Amino Glycoside ◽  
Hydrolysis Of

Treatment of methyl 3,6-dideoxy-2,4-di-O-methylsulfonyl-3-nitro-α-L-glucopyranoside (2) with sodium acetate and acetic acid in acetone gave methyl 4-O-acetyl-2,3,6-trideoxy-3-nitro-α-L-erythro-hex-2-enopyranoside (3) as a kinetic product, and the 2-O-acetyl-3,4,6-trideoxy-3-nitro-α-L-threo-hex-3-eno isomer 4 as the thermodynamically preferred product. Treatment of 2 or 4 with sodium borohydride produced a separable mixture of methyl 2,3,4,6-tetradeoxy-3-nitro-α-L-threo-hexopyranoside (5) and its α-L-erythro epimer (6), the latter being convertible into the former by base-catalyzed epimerization. Acid hydrolysis of 5 and 6 afforded the corresponding free nitro sugars 7 and 8. Catalytic hydrogenation of 5 led to the corresponding amino glycoside, isolated as the acetate 9 or hydrochloride 10; similarly, 6 gave the epimeric amine which was isolated as its acetate 14 or picrate 15. N-Trifluoroacetylation of 9 provided the N-trifluoroacetyl glycoside 12 which was hydrolyzed to give a 49% yield (overall from 2) of 2,3,4,6-tetradeoxy-3-trifluoroacetamido-L-threo-hexose (4-deoxy-N-trifluoroacetyldaunosamine, 13). Analogously, 14 afforded the epimeric N-trifluoroacetyl glycoside 17 which was hydrolyzed to give a 28% overall yield of 2,3,4,6-tetradeoxy-3-trifluoroacetamido-L-erythro-hexose (4-deoxy-N-trifluoroacetylristosamine, 18).

CONSTITUTION OF A DEGRADED POLYSACCHARIDE FROM WHEAT BRAN

1957 ◽  
Vol 35 (2) ◽  
pp. 108-114 ◽  
Author(s):  
J. Schmorak ◽  
C. T. Bishop ◽  
G. A. Adams
Keyword(s):  
Acid Hydrolysis ◽  
Wheat Bran ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Glycosidic Bond ◽  
Cellulolytic Enzyme ◽  
Acidic Polysaccharide ◽  
Hydrolysis Of ◽  
End Group ◽  
Acid Unit

Graded acid hydrolysis of a soluble wheat bran hemicellulose containing L-arabinose (50%), D-xylose (38.5%), and D-glucuronic acid (9.0%) preferentially removed the L-arabinose giving an insoluble acidic polysaccharide in approximately 25% yield by weight. Methylation studies, periodate oxidation data, and hypoiodite end group estimations showed that the degraded polysaccharide was composed of repeating units of 7-8 D-xylopyranose residues joined by β,1 → 4 linkages. To this repeating unit, one D-glucuronic acid unit was attached by a 1 → 2 glycosidic bond. The cellulolytic enzyme of Myrotheciumverrucaria, which is specific for β,1 → 4 glycosidic linkages, hydrolyzed the degraded polysaccharide although it had no effect on the parent hemicellulose

Syothesis of 3-Deoxy-3-nitro-D-xylose

1971 ◽  
Vol 49 (19) ◽  
pp. 3238-3239 ◽  
Author(s):  
Jan Kovář ◽  
Hans H. Baer
Keyword(s):  
Acid Hydrolysis ◽  
Title Compound ◽  
Periodate Oxidation ◽  
Borohydride Reduction ◽  
Hydrolysis Of

Crystalline 3-deoxy-3-nitro-α-D-xylose (5) was obtained in 40% over-all yield by periodate oxidation of 3-deoxy-1,2-O-isopropylidene-3-nitro-α-D-glucofuranose (2) followed by borohydride reduction and acid hydrolysis. In addition to the intermediate 3-deoxy-1,2-O-isopropylidene-3-nitro-α-D-xylofuranose (4), a small amount of an isomer probably having the D-ribo configuration was isolated. The title compound (5) was also obtained by hydrolysis of its methyl β-pyranoside (1).

Stereospecific synthesis of isomeric 4-substituted 9-(2,3-dihydroxybutyl)adenines

1982 ◽  
Vol 47 (1) ◽  
pp. 173-189 ◽  
Author(s):  
Antonín Holý
Keyword(s):  
Acid Hydrolysis ◽  
Sodium Borohydride ◽  
Sodium Salt ◽  
Catalytic Hydrogenation ◽  
Sodium Azide ◽  
Sodium Iodide ◽  
Stereospecific Synthesis ◽  
Isopropylidene Derivative

Reduction of ethyl 2,3-O-isopropylidene-D-tartrate with sodium borohydride afforded (4S, 5S)-2,2-dimethyl-1,3-dioxolane-4,5-dimethanol (Va) which was benzoylated to give monobenzoyl derivative Vd and further transformed into p-toluensulfonyl derivative Ve. Reaction of the compound Ve with sodium salt of adenine followed by methanolysis gave 2,3-O-isopropylidene derivative Vf which on acid hydrolysis afforded 9-(2S, 3S)-(2,3,4-trihydroxybutyl)adenine (Ia). The enantiomer IIa was obtained from 3,4-O-isopropylidene-D-mannitol via (4R, 5R)-2,2-dimethyl-1,3-dioxolane-4,5-dimethanol (VIa) using the same procedure. Reaction of compounds Vf and VIf with p-toluenesulfonyl chloride afforded 4-O-p-toluenesulfonyl derivatives Vg and VIg. These compounds were also obtained from Va and VIa via di-p-toluenesulfonyl derivatives Vc and VIc by reaction with sodium salt of adenine. Treatment of compounds Vg and VIg with sodium iodide gave 4-iodo derivatives Vh and VIh which on reaction with tri-n-butyltin hydride, followed by acid hydrolysis, afforded enantiomeric threo-2,3-dihydroxybutyl derivatives Ib andIIb. Compounds Vg and VIg on treatment with sodium azide, subsequent catalytic hydrogenation of the intermediates Vj and VIj and acid hydrolysis afforded enantiomeric threo-9-(4-amino-2,3-dihydroxybutyl)adenines (Ic,IIc).

Complexes of Nickel(II) and Copper(II) With 5,5,7-Trimethyl-1,4-Diazepane. Preparation and Kinetics of Acid-Hydrolysis

1986 ◽  
Vol 39 (2) ◽  
pp. 239 ◽  
Author(s):  
NF Curtis
Keyword(s):  
Acid Hydrolysis ◽  
Acid Concentration ◽  
Reaction Rates ◽  
Borohydride Reduction ◽  
Kinetics Of Hydrolysis ◽  
Rapid Reaction ◽  
Kinetics Of ◽  
Hydrolysis Of

The cyclic diamine 5,5,7-trimethyl-1,4-diazepane, tmdz, is formed by borohydride reduction of 5,7,7-trimethyl-2,3,6,7-tetrahydro-1H-1,4- diazepine , which is formed by a rapid reaction between ethanediamine and 4-methylpent-3-en-2-one. Salts of the cations [Ni( tmdz )2]2+ and [Cu( tmdz )2]2+ were prepared, and their properties are reported. The kinetics of hydrolysis of [Ni( tmdz )2]2+ and [Cu( tmdz )2]2+ and bis (1,4- diazepane )nickel(II), [Ni( dach )2]2+, in aqueous HCl/NaCl media have been studied. Reaction rates are independent of acid concentration over the ranges used . Ni2+,0.1-1 mol l-1 H+ in 1 mol l-1 Cl -, kobs(25°C) = 9.1(1)×10-7 s-1, kobs(50°C) = 2.0(1)×10-5 s-1,ΔH‡96(2)kJ mol-1,0.08-4 mol l-1, H+ in 4 mol l-1 Cl -, kobs (25°pC) = 2.0(3)°10-7 s-1. Cu2+, 0.04-1 mol l-1 H+, 1 mol l-1 Cl -, kobs (25°C) = 0.028(2) s-1, for the displacement of the second ligand . [Ni( dach )2]2+, 0.1-1 mol l-1 H+, 1 mol l-1 Cl -, kobs (25°C) = 0.051(2) s-1. [Ni( tmdz )2]2+ reacts more rapidly with NaOH/edta : 1 mol l-1 NaOH , 0.1 mol l-1, Na2(edtaH2), kobs (25°C) = 7.3(3)×10-3 s-1, 0.5 mol l-1 NaOH , 0.1 mol l-1 Na2(edtaH2), kobs (25°C) = 4.5(3)×10-3 s-1.

THE STRUCTURAL ANALYSIS OF SOME ACIDIC XYLANS BY PERIODATE OXIDATION

1962 ◽  
Vol 40 (2) ◽  
pp. 348-352 ◽  
Author(s):  
G. G. S. Dutton ◽  
A. M. Unrau
Keyword(s):  
Acid Hydrolysis ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Small Degree ◽  
Degree Of Polymerization ◽  
Borohydride Reduction ◽  
Mild Acid Hydrolysis ◽  
Degree Of Branching ◽  
Hydrolysis Of ◽  
Mild Acid

By determining the amount of formaldehyde produced on periodate oxidation of borohydride-reduced apple- and cherry-wood xylans the degree of polymerization was shown to be 155 and 100 respectively. Acid hydrolysis of the polyols obtained by periodate oxidation and borohydride reduction gave ethylene glycol in amounts indicating that these xylans have a small degree of branching. Mild acid hydrolysis of the polyols demonstrated that in these xylans D-glucuronic acid as well as 4-O-methyl-D-glucuronic acid was present and that some of the former occupied non-terminal positions.

The use of catalytic hydrogenation to intercept carbohydrates in a dilute acid hydrolysis of biomass to effect a clean separation from lignin

2004 ◽  
Vol 26 (5) ◽  
pp. 473-483 ◽  
Author(s):  
J. Michael Robinson ◽  
Caroline E. Burgess ◽  
Melissa A. Bently ◽  
Chris D. Brasher ◽  
Bruce O. Horne ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Catalytic Hydrogenation ◽  
Dilute Acid ◽  
Dilute Acid Hydrolysis ◽  
Hydrolysis Of

Preparation of enantiomeric and racemic 2,3,4,5-tetrahydroxypentyl derivatives of adenine, cytosine and uracil

1982 ◽  
Vol 47 (10) ◽  
pp. 2786-2805 ◽  
Author(s):  
Antonín Holý
Keyword(s):  
Acid Hydrolysis ◽  
Sodium Borohydride ◽  
Catalytic Hydrogenation ◽  
Protecting Groups ◽  
Sodium Salts ◽  
Hydrolysis Of ◽  
Derivatives Of ◽  
Subsequent Acid

1-(Adenin-9-yl)-1-deoxy-DL-ribitol (III), -D-arabitol (IXa), -L-arabitol (XIVa), -DL-xylitol (XXIVa), 1-(cytosin-L-yl)-1-deoxy-D-arabitol (IXb), -L-arabitol (XIVb), 1-(uracil-1-yl)-1-deoxy-D-arabitol (IXc), -L-arabitol (XIVc) and -DL-xylitol (XXIVb) were prepared by reaction of 1-O-p-toluenesulfonyl-2,3:4,5-di-O-isopropylidenealditols Ib, VIIb, XIIb and XXIIb with sodium salts of adenine, N4-benzoylcytosine or 4-methoxy-2-pyrimidone followed by removal of the protecting groups. Condensation of the mentioned sodium salts with methyl 5-O-p-toluenesulfonyl-2,3-O-isopropylidene-β-D-ribofuranoside (IV) with subsequent acid hydrolysis and reduction with sodium borohydride afforded 1-(adenin-9-yl)-1-deoxy-L-ribitol (VIa) and 1-(cytosin-1-yl)-1-deoxy-L-ribitol (VIb). 1-(Adenin-9-yl)-1-deoxy-L-lyxitol (XVII), -L-lyxitol (XVIII) and -2-O-methyl-D-lyxitol (XXI) were prepared analogously. Acid hydrolysis of 5-(adenin-9-yl)-5-deoxy-4-O-benzyl-1,2-O-isopropylidene-α-D-xylofuranose (XXVa), followed by reduction with sodium borohydride and catalytic hydrogenation, gave 1-(adenin-9-yl)-1-deoxy-L-xylitol (XXVIb).

Medium heterocyclic rings from carbohydrate precursors

1968 ◽  
Vol 46 (19) ◽  
pp. 3061-3069 ◽  
Author(s):  
J. F. Stoddart ◽  
W. A. Szarek
Keyword(s):  
Acid Hydrolysis ◽  
Spectral Data ◽  
Borohydride Reduction ◽  
Methyl Derivative ◽  
Partial Acid Hydrolysis ◽  
Physical Evidence ◽  
Quantitative Measurements ◽  
Conformational Properties ◽  
Hydrolysis Of

Chemical and physical evidence is presented to show that the structure of a dianhydride of D-ribose is di-β-D-ribofuranose 1,5′:1′,5-dianhydride. Partial acid hydrolysis of this dimer affords a ribobiose, which is shown to be 5-O-β-D-ribofuranosyl-D-ribose, since examination of the O-methyl derivative of this disaccharide yields 2,3,5-tri- and 2,3-di-O-methyl-D-ribose, and since quantitative measurements of the periodate consumption of the derived glycitol (4 moles of periodate per mole) are consistent with a structure corresponding to 5-O-β-D-ribofuranosyl-D-ribitol. In addition to confirming that both the 1 → 5′- and 1′ → 5- linkages have the β configuration, n.m.r. spectral data for the dianhydride tetraacetate leads to a conformational assignment for this derivative in chloroform at room temperature.Periodate oxidation of the dianhydride, followed by borohydride reduction and acetylation, yields a 2,4,7,9-tetraacetoxymethyl-1,3,6,8-tetraoxacyclodecane. The conformational properties of this compound are discussed.

The structure and function of oestrogens. V. Synthesis of (9,12,12-2H3)- and (11ζ 12,12-2H3)-oestradiol

1983 ◽  
Vol 36 (2) ◽  
pp. 403 ◽  
Author(s):  
DJ Collins
Keyword(s):  
Acid Hydrolysis ◽  
Sodium Borohydride ◽  
Structure And Function ◽  
Borohydride Reduction ◽  
Hydride Reduction ◽  
Biological Studies ◽  
Sodium Borohydride Reduction ◽  
And Function ◽  
Hydrolysis Of

17,17-Ethylenedioxy-3-methoxy(9,12,12-2H3)-9β-oestra-l,3,5(10)-trien-11-one (3) was reduced to the mixture of 11-epimeric alcohols (4) which upon elimination of DHO gave the (12,12-2H2)-9(11)- dehydrooestrone derivative (5b). Treatment of (5b) with (2H6)diborane followed by oxidation afforded the (9,12,12-2H3)alcohol (8a); hydride reduction of the corresponding tosylate then gave 17,17-ethylenedioxy-3-methoxy(9,12,12-2H3)oestra-l,3,5(l0)-triene (7). Acid hydrolysis of (7), followed by demethylation, and reduction with sodium borohydride yielded (9,12,12-2H3)oestradiol (10). Sodium borohydride reduction of (11&12,12-2H3)oestrone (6),prepared in several steps from the 9β,12,12-trideutero ketone (3), gave (11 ξ,12,12-2H3)oestradiol (9). [The two trideuterated oestradiols (9) and (10) were required for biological studies.]

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