THE BROMINOLYSIS OF CARBOHYDRATE IODIDES: I. ACETYLATED 6-DEOXY-6-IODO AND 2-DEOXY-2-IODO GLYCOSIDES

1964 ◽  
Vol 42 (3) ◽  
pp. 539-546 ◽  
Author(s):  
R. U. Lemieux ◽  
B. Fraser-Reid
Keyword(s):  
Acetic Acid ◽  
Methoxy Group ◽  
Glacial Acetic Acid ◽  
Main Product ◽  
Zinc Dust ◽  
Potassium Acetate ◽  
Borohydride Reduction ◽  
Silver Acetate ◽  
Sodium Borohydride Reduction ◽  
Dust Reduction

Reaction of methyl 6-deoxy-6-iodo-α-D-glucopyranoside triacetate with an excess of bromine in glacial acetic acid; N in potassium acetate, gave a 1.1:1 mixture of the products resulting from replacement of the iodine by bromine and by acetoxy group, respectively. When 2 moles of silver acetate were present per mole of bromine, the reaction was much more rapid and only methyl α-D-glucopyranoside tetraacetate was formed. The brominolysis of methyl 2-deoxy-2-iodo-α-D-mannopyranoside triacetate proceeded at a useful rate only when catalyzed by silver acetate. The main product of the reaction appeared to be methyl 3-acetoxy-2-bromo-2-deoxy-α-D-arabino-hexopyranoside triacetate. The compound could be converted by way of sodium borohydride reduction to methyl 2-bromo-2-deoxy-α-D-altropyranoside and by way of zinc dust reduction to methyl 2-deoxy-α-D-erythro-hexopyranoside-3-ulose diacetate. About 20% of the reaction proceeded with migration of the methoxy group to the 2-position to yield 2-O-methyl-D-glucose tetraacetate. The mechanisms of these reactions are discussed.

scholarly journals Eine neue Methode zur Herstellung und Reinigung von 5-Methyltetrahydrofolsäure / A New Method for Preparation and Purification of 5-M ethyltetrahydrofolic Acid

1973 ◽  
Vol 28 (11-12) ◽  
pp. 650-652
Author(s):  
Harold Rüdiger ◽  
Reinhard Siede
Keyword(s):  
Acetic Acid ◽  
Folic Acid ◽  
Ion Exchange ◽  
Sodium Borohydride ◽  
Sodium Salt ◽  
Barium Salt ◽  
Borohydride Reduction ◽  
Methyl Derivative ◽  
Crude Product ◽  
Sodium Borohydride Reduction

Abstract 5-Methyltetrahydrofolic acid is prepared from folic acid by sodium borohydride reduction, reac­ tion with formaldehyde and reduction to the methyl derivative by sodium borohydride. The crude product is precipitated as barium salt which after having been converted to the sodium salt by ion exchange is adsorbed to QAE-Sephadex and eluted by different acetic acid gradients in subsequent chromatographies. This method allows to process gram quantities on reasonably small columns

Synthesis and Structure of 1-Substituted Benzopyrano- [4’,3’-c]benzo[3”,4”-ƒ]-2,8-dioxabicyclo[3.3.1]nonane

2006 ◽  
Vol 61 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Ilia Manolov ◽  
Caecilia Maichle-Moessmer ◽  
Elke Niquet
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Condensation Reaction ◽  
Potassium Acetate

AbstractThe base catalyzed condensation reaction between 4-hydroxycoumarin and 3-acetylcoumarin (3-benzoylcoumarin) in water at reflux led to the formation of 1-methyl (1-phenyl)- benzopyrano[4’,3’-c]-benzo[3”,4”-ƒ ]-2,8-dioxabicyclo[3.3.1]nonane (2a, b) as final products. When 4-hydroxycoumarin and 3-acetylcoumarin reacted in a glacial acetic acid in the presence of potassium acetate the final product was 7-[3-acetyl-2-oxo-3,4-dihydro-2H-[1]benzopyran-4-yl]methyl- 6H,14H,14bH-bis-([1]benzopyrano)[4,3-b:4’,3’-d]pyran-6,14-dione (4). 4-Hydroxycoumarin and 4-(5-bromo-2-hydroxyphenyl)-3-buten-2-one were condensed in water at reflux and 1- methylcoumarino-[4’,3’-c]-bromobenzo[3”,4”-ƒ ]-2,8-dioxabicyclo[3.3.1]nonane was a final product (3).

scholarly journals Zwitterionic Acetylated Cellulose Nanofibrils

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3147 ◽  
Author(s):  
Jowan Rostami ◽  
Aji P. Mathew ◽  
Ulrica Edlund
Keyword(s):  
Acetic Acid ◽  
Schiff Base ◽  
Reaction Time ◽  
Structural Changes ◽  
Glacial Acetic Acid ◽  
Cellulose Nanofibrils ◽  
Periodate Oxidation ◽  
Hydroxyl Groups ◽  
Borohydride Reduction ◽  
Short Reaction Time

A strategy is devised to synthesize zwitterionic acetylated cellulose nanofibrils (CNF). The strategy included acetylation, periodate oxidation, Schiff base reaction, borohydride reduction, and a quaternary ammonium reaction. Acetylation was performed in glacial acetic acid with a short reaction time of 90 min, yielding, on average, mono-acetylated CNF with hydroxyl groups available for further modification. The products from each step were characterized by FTIR spectroscopy, ζ-potential, SEM-EDS, AFM, and titration to track and verify the structural changes along the sequential modification route.

Alkaline Degradation of Inulin and Its Structural Implications

1967 ◽  
Vol 13 (4) ◽  
pp. 261-269 ◽  
Author(s):  
J N BeMiller ◽  
T R Steinheimer ◽  
Earl E Allen
Keyword(s):  
Calcium Hydroxide ◽  
Sodium Borohydride ◽  
Main Product ◽  
Alkaline Degradation ◽  
Borohydride Reduction ◽  
Hydroxide Solution ◽  
Controlled Conditions ◽  
Sodium Borohydride Reduction ◽  
Clinical Measurements ◽  
Different Sources

Abstract Alkaline degradation of inulin under controlled conditions shows that not all molecules in an inulin preparation are nonreducing and, thus, alkali-stable and suitable for clinical measurements. Reducing "inulin" molecules are degraded by the normal beta-alkoxy carbonyl mechanism, and the main product of degradation in calcium hydroxide solution is "α"-D-glucosaccharinic acid. An inulin preparation can be made alkali- stable by sodium borohydride reduction. There appears to be a difference in the alkali lability of inulin and other fructan preparations obtained from different sources.

scholarly journals Lead Tetra-Acetate/Schiff Tests in Histochemistry

1954 ◽  
Vol s3-95 (31) ◽  
pp. 323-325
Author(s):  
W. G. BRUCE CASSELMAN
Keyword(s):  
Acetic Acid ◽  
Acid Solution ◽  
Glacial Acetic Acid ◽  
Acetic Acid Solution ◽  
Potassium Acetate ◽  
Lead Tetra Acetate

Certain polysaccharides, such as starch and glycogen, do not give consistently positive or negative reactions with all lead tetra-acetate/Schiff techniques. This depends upon the conditions under which the oxidant is used. A simple glacial acetic acid solution of lead tetra-acetateis least active but most specific. Added potassium acetate acts as a catalyst. Dilution with water not only increases the activity of the reagent but also decreases the specificity of the test.

A COMPARISON OF THE PROPERTIES OF PENTAACETATES AND METHYL 1,2-ORTHOACETATES OF GLUCOSE AND MANNOSE

1955 ◽  
Vol 33 (1) ◽  
pp. 109-119 ◽  
Author(s):  
R. U. Lemieux ◽  
Carol Brice
Keyword(s):  
Acetic Acid ◽  
Hydrochloric Acid ◽  
Zinc Chloride ◽  
Main Product ◽  
Stannic Chloride ◽  
Aqueous Acetic Acid ◽  
Silver Acetate ◽  
Silver Carbonate ◽  
Ethyl Mercaptan ◽  
Glucose Pentaacetate

The rates of exchange of acetate—concurrent with anomerization—between the C1-acetoxy groups of the pentaacetates (0.05 M) of D-glucose and D-mannose and stannic trichloride acetate (0.05 M) in chloroform containing stannic chloride (0.05 M) were determined at 40 °C. using isotopically labelled acetate. 1,2-trans-α-D-Mannose pentaacetate underwent exchange seven times more rapidly than the β-1,2-cis-anomer but eight times less rapidly than 1,2-trans-β-D-glucose pentaacetate. The latter compound was 450 times more reactive than the α-1,2-cis-anomer. In accordance with these results, the D-mannose pentaacetate underwent mercaptolysis in ethyl mercaptan containing zinc chloride at rates intermediate to those found for the D-glucose pentaacetates. The main product from the mannose pentaacetates was in each case ethyl 1,2-trans-α-D-1-thiomannopyranoside tetraacetate (60–70% yield). Tetra-O-acetyl-β-D-glucopyranosyl chloride with silver acetate gave β-D-glucose pentaacetate when the reaction was carried out in dry acetic acid but gave 2,3,4,6-tetra-O-acetyl-α-D-glucose in 90% aqueous acetic acid. Tetra-O-acetyl-β-D-glucopyranosyl chloride with methanol and silver carbonate gave a sirupy product with the properties expected for methyl 1,2-ortho-O-acetyl-α-D-glucopyranose triacetate. The substance was hydrolyzed by 0.005 N hydrochloric acid in 95% dioxane 18 times more rapidly than the corresponding derivative of β-D-mannose. The significance of these observations toward an understanding of the effect of configuration on reactivity is discussed.

Steroidal α,β-epoxyketones. IV. Synthesis of the isomeric 6β-Bromo-4,5-epoxycholestan-3-ones

1965 ◽  
Vol 18 (7) ◽  
pp. 1049 ◽  
Author(s):  
DJ Collins ◽  
JJ Hobbs
Keyword(s):  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Sodium Borohydride ◽  
Hydrogen Bromide ◽  
High Yield ◽  
Borohydride Reduction ◽  
Compound Xiii ◽  
Alkaline Hydrogen Peroxide ◽  
Sodium Borohydride Reduction

6β-Bromocholest-4-en-3-one (I) was converted to 6β-bromo-4α,5-epoxy-5α-cholestan-3-one (II) with alkaline hydrogen peroxide. 5,6β-Dibromo-5α-cholestane- 3β,4β-diol (X) with alkali gave 6β-bromo-4β,5-epoxy-5β-cholestan-3β-ol (IXa), which was oxidized to non-crystalline 6β-bromo-4β,5-epoxy-5β-cholestan-3-one (XIII), characterized as the crystalline 3,3-dimethyl ketal (XIIa). Cleavage of (II) with hydrogen bromide in acetic acid gave 4,6β-dibromocholest-4-en-3-one (V) via the isomeric bromohydrins (IVa) and (IVb). Compound (XIII) yielded (V) directly. Sodium borohydride reduction of (I) gave cholesterol in high yield, while reduction with lithium tri-t-butoxyaluminium hydride afforded cholest-4-en-3-one (52%), cholesterol (30%), and cholest-4-en-6β-ol-3-one (7%).

STUDY OF HALOGENATED HYDROXYPHENAZINES

1957 ◽  
Vol 35 (12) ◽  
pp. 1423-1433 ◽  
Author(s):  
Paul E. Gagnon ◽  
Karl F. Keirstead ◽  
Brian T. Newbold
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Thermal Decomposition ◽  
Acetic Acid ◽  
Absorption Spectra ◽  
Glacial Acetic Acid ◽  
Zinc Dust ◽  
Sodium Perborate ◽  
Chemical Evidence

The properties of chlorotrihydroxydihydrophenazine were thoroughly investigated. Oxidations with sodium perborate or hydrogen peroxide in glacial acetic acid gave chloro-trihydroxyphenazine-5,10-dioxide. Methylation gave a monomethyl derivative and acetylation yielded mono-, di-, and tri-acetyl derivatives. Benzoylation gave a tetrabenzoyl compound. Bromination gave a monobromo derivative. Nitrosation produced a mononitroso and nitration a mononitro compound. Degradation by zinc dust distillation and thermal decomposition yielded phenazine. Molecular weight and absorption spectra determinations supported the chemical evidence that the compound was 1-chloro-2(or 3),6,8-trihydroxydihydrophenazine. 1,4,9-Trichloro-2(or 3),6,8-trihydroxydihydrophenazine, 1,4,9-trichloro-2(or 3, or 8),6-dihy-droxydihydrophenazine, and 1-bromo-2(or 3),6,8-trihydroxydihydrophenazine were similarly identified.

THE BROMINOLYSIS OF CARBOHYDRATE IODIDES: II. A SYNTHETIC ROUTE TO 2,5-ANHYDROSUGARS

1964 ◽  
Vol 42 (3) ◽  
pp. 547-549 ◽  
Author(s):  
R. U. Lemieux ◽  
B. Fraser-Reid
Keyword(s):  
Acetic Acid ◽  
Hydrogen Chloride ◽  
Potassium Acetate ◽  
Quantitative Yield ◽  
Equimolar Mixture ◽  
Silver Acetate ◽  
Synthetic Route ◽  
Fold Excess

Reaction of methyl 2-deoxy-2-iodo-β-D-glucopyranoside triacetate with a 20-fold excess of bromine and a 10-fold excess of silver acetate in a 10% solution of potassium acetate in acetic acid gave a near-quantitative yield of an equimolar mixture of the anomeric forms of 1,3,4,6-tetra-O-acetyl-2,5-anhydro-1-methoxy-D-mannose. Treatment of the mixture with methanolic hydrogen chloride gave the dimethylacetal of 2,5-anhydro-D-mannose (chitose).

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