Preparation of conjugates of uridine with proteins by the imido ester condensation method

1981 ◽  
Vol 46 (4) ◽  
pp. 933-940 ◽  
Author(s):  
Helmut Pischel ◽  
Antonín Holý ◽  
Günther Wagner
Keyword(s):  
Human Serum ◽  
Acid Hydrolysis ◽  
Ester Hydrochloride ◽  
Protein Conjugates ◽  
Condensation Method ◽  
Ester Condensation ◽  
Acid Catalyzed

Reaction of 5'-O-p-toluenesulfonyl-2',3'-O-isopropylideneuridine (I) with sodium 4-cyanophenoxide afforded 2',3'-O-isopropylidene-5'-O-(4-cyanophenyl)uridine (II) which was converted by acid hydrolysis into 5'-O-(4-cyanophenyl)uridine (IIIa). Acid-catalyzed addition of ethanol to compound IIIa gave the imido ester hydrochloride IIIb which on reaction with ammonia or ethylamine was transformed into the amidine derivatives IIIc and IIId. Compound IIIb reacted with human serum albumine or bovine gamma-globuline at pH 9.2 to give protein conjugates with uridine, bound covalently by an amidine bond (IIIe,f).

THE ACID HYDROLYSIS OF GLYCOSIDES: I. GENERAL CONDITIONS AND THE EFFECT OF THE NATURE OF THE AGLYCONE

1964 ◽  
Vol 42 (6) ◽  
pp. 1456-1472 ◽  
Author(s):  
T. E. Timell
Keyword(s):  
Acid Hydrolysis ◽  
Equilibrium Concentration ◽  
Rate Coefficients ◽  
Acidity Function ◽  
Tertiary Alcohols ◽  
Conjugate Acid ◽  
Rate Of Hydrolysis ◽  
Acid Catalyzed ◽  
Opposing Effects ◽  
Hydrolysis Of

First-order rate coefficients and energies and entropies of activation have been determined for the acid-catalyzed hydrolysis of a number of methyl D-glycopyranosides and disaccharides. The relation between the logarithm of the rate coefficients and values for Hammett's acidity function was linear, although different for different acids. All compounds had entropies of activation indicating a unimolecular reaction mechanism. Glucosides of tertiary alcohols were hydrolyzed very rapidly, triethylmethyl β-D-glucopyranoside, for example, 30,000 times taster than the corresponding methyl compound.Increase in size of the aglycone caused a slight increase in the rate of hydrolysis of β-D-glucopyranosides, steric hindrance thus being of no significance. Electron-attracting substituents in the aglycone had little or no influence on the rate of hydrolysis, obviously because they would tend to lower the equilibrium concentration of the conjugate acid, while facilitating the subsequent heterolysis, the two opposing effects more or less cancelling out. These results were discussed in connection with recent studies on the acid hydrolysis of various phenyl glycopyranosides and with reference to the postulated occurrence of an activating inductive effect in oligo- and poly-saccharides containing carboxyl or other electronegative groups at C-5. It was concluded that there is little evidence for the existence of any such effect and that, for example, pseudoaldobiouronic acids should be hydrolyzed at the same rate as corresponding neutral disaccharides.

ChemInform Abstract: Synthesis of Optically Active 2-Chloromethyl-2-oxazolines by the Ortho-Ester Condensation Method Using Triethyl Orthochloroacetate.

ChemInform ◽  
2010 ◽  
Vol 30 (25) ◽  
pp. no-no
Author(s):  
Kazuyuki Kamata ◽  
Hideki Sato ◽  
Emi Takagi ◽  
Isao Agata ◽  
A. I. Meyers
Keyword(s):  
Optically Active ◽  
Ortho Ester ◽  
Condensation Method ◽  
Ester Condensation

Synthesis of 3-amino- and 3-azidoanalogs of 9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA)

1989 ◽  
Vol 54 (2) ◽  
pp. 446-454 ◽  
Author(s):  
Antonín Holý
Keyword(s):  
Acid Hydrolysis ◽  
Sodium Salt ◽  
Catalytic Hydrogenation ◽  
Alkaline Hydrolysis ◽  
Benzoyl Chloride ◽  
Sodium Hydride ◽  
Acid Catalyzed ◽  
Excess Sodium ◽  
Chloride Treatment

1-Azidopropane-2,3-diol (IIb) reacts with p-toluenesulfonyl chloride to give the tosyl derivative IIIa which, on acid catalyzed condensation with 2,3-dihydropyran, afforded 1-azido-2-(tetrahydropyran-2-yloxy-3-(p-toluenesulfonyloxy)propane (IIIb). Treatment of adenine sodium salt with IIIb resulted in the intermediate IV which was transformed by acid hydrolysis to 9-(RS)-(3-azido-2-hydroxypropyl)adenine (V). Catalytic hydrogenation of V led to 9-(RS)-(3-amino-2-hydroxypropyl)adenine (VI). 9-(RS)-(3-Azido-2-hydroxypropyl)-N6-benzoyladenine (VII) was obtained from V by chlorotrimethylsilane/benzoyl chloride treatment. Reaction of the compound VII with dimethyl p-toluenesulfonyloxymethanephosphonate (VIII) in the presence of excess sodium hydride, followed by alkaline hydrolysis, afforded methyl 9-(3-azido-2-phosphonylmethoxypropyl)adenine (IXa) which was transformed to the parent acid IXb by bromotrimethylsilane treatment. Hydrogenolysis of IXb yielded 9-(RS)-(3-amino-2-phosphonylmethoxypropyl)adenine (X).

Synthesis and Acid-Catalyzed Hydrolysis of Some 3-(4-Methoxyphenyl)propyl Glucuronates

2000 ◽  
Vol 65 (10) ◽  
pp. 1609-1618 ◽  
Author(s):  
Monika Poláková ◽  
Dušan Joniak ◽  
Miloslav Ďuriš
Keyword(s):  
Acid Hydrolysis ◽  
Acid Catalyzed ◽  
Model Substances ◽  
Hydrolysis Of

3-(4-Methoxyphenyl)propyl D-glucuronate, 3-(4-methoxyphenyl)propyl methyl 4-O-methyl-α-Dglucopyranosiduronate, 3-(4-methoxyphenyl)propyl 1,2,3,4-tetra-O-acetyl-α-D-glucopyranuronate and 3-(4-methoxyphenyl)propyl 1,2-(S):3,5-di-O-benzylidene-α-D-glucofuranuronate were prepared as a model substances for the ester lignin-saccharide bonds. Rates of acid-catalyzed hydrolysis of the prepared compounds in 1 M HCl in acetonitrile-water 3 : 1 at 20 °C have been measured by LC-DAD analysis and it showed the low stability of the ester bonds towards acid hydrolysis.

scholarly journals Obtaining Fermentable Sugars from a Highly Productive Elm Clone Using Different Pretreatments

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2415
Author(s):  
David Ibarra ◽  
Raquel Martín-Sampedro ◽  
Laura Jiménez-López ◽  
Juan A. Martín ◽  
Manuel J. Díaz ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Fossil Fuels ◽  
Dutch Elm Disease ◽  
Fermentable Sugars ◽  
Alkaline Extraction ◽  
Enzymatic Digestibility ◽  
Dilute Acid Hydrolysis ◽  
Yield Production ◽  
Acid Catalyzed ◽  
Favorable Conditions

The interest of supplying lignocellulosic materials for producing fermentable sugars has recently emerged in order to diminish the negative environmental effects of fossil fuels. In this study, the Ulmus minor clone Ademuz, characterized for its tolerance to Dutch elm disease and its rapid growth, was evaluated as a source of fermentable sugars. For that, different pretreatments, comprising autohydrolysis, dilute acid hydrolysis, acid catalyzed organosolv, and alkaline extraction, were evaluated at two levels of severity (pretreatment temperatures at 160 °C and 180 °C, except for alkaline extraction at 80 °C and 160 °C); and the resulting pretreated materials were enzymatically hydrolyzed for fermentable sugars production. The major extraction of lignin and hemicellulose was achieved during organosolv (48.9%, lignin; 77.9%, hemicellulose) and acid hydrolysis (39.2%, lignin; 95.0%, hemicellulose) at 180 °C, resulting in the major enzymatic digestibility (67.7%, organosolv; 53.5% acid hydrolysis). Contrarily, under the most favorable conditions for autohydrolysis (180 °C) and alkaline extraction (160 °C), lower extraction of lignin and hemicellulose was produced (4.8%, lignin; 67.2%, hemicellulose, autohydrolysis; 22.6%, lignin; 33.1%, hemicellulose, alkaline extraction), leading to lower enzymatic digestibility (32.1%, autohydrolysis; 39.2%, alkaline extraction). Taking into account the sugars produced during enzymatic hydrolysis of pretreated materials and the solubilized sugars from pretreatment liquors, the highest sugars (glucose and xylose) yield production (28.1%) per gram of biomass from U. minor clone Ademuz was achieved with acid catalyzed organosolv at 180 °C.

RAPID PURIFICATION OF TRI-IODOTHYRONINE AND THYROXINE PROTEIN CONJUGATES FOR ANTIBODY PRODUCTION

1975 ◽  
Vol 65 (1) ◽  
pp. 133-138 ◽  
Author(s):  
C. W. BURKE ◽  
R. A. SHAKESPEAR
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Antibody Production ◽  
Guinea Pigs ◽  
High Titre ◽  
Adsorption Chromatography ◽  
Protein Conjugates ◽  
Rapid Purification ◽  
Dialysis Technique

SUMMARY Thyroxine (T4) and tri-iodothyronine (T3) were coupled to human serum albumin (HSA) with carbodi-imide. By adsorption chromatography on Sephadex G-25, fractions containing purified conjugate, but not reversibly-bound T3 or T4, were obtained, and this procedure took 5 h; considerably less than the conventional dialysis technique. Highly specific high-titre antisera were produced in rabbits and guinea-pigs by injection of these fractions in Freund's adjuvant.

Total Synthesis of DL-Glucose, 3-O-Methyl-DL-glucose, and 3-Deoxy-DL-ribo-hexopyranose from 1,6:3,4-Dianhydro-β-DL-allo-hexopyranose, a Product Obtained from Acrolein Dimer

1971 ◽  
Vol 49 (20) ◽  
pp. 3342-3347 ◽  
Author(s):  
U. P. Singh ◽  
R. K. Brown
Keyword(s):  
Total Synthesis ◽  
Acid Hydrolysis ◽  
Sodium Methoxide ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Barium Hydroxide ◽  
Lithium Aluminum ◽  
Methyl Glycoside ◽  
Acid Catalyzed ◽  
Hydrolysis Of

The reaction of butyllithium in ether with 1,6:2,3-dianhydro-4-deoxy-β-DL-ribo-hexopyranose (1), a substance obtained in five steps from acrolein dimer, gave 1,6-anhydro-3,4-dideoxy-β-DL-erythro-hex-3-enopyranose (2). The compound 1,6:3,4-dianhydro-β-DL-allo-hexopyranose (3), obtained from 2, was converted by reaction with aqueous barium hydroxide followed by hydrolysis of the product, to DL-glucose 5. Treatment of 3 with sodium methoxide in methanol followed by acid hydrolysis of the 1,6-anhydro intermediate 6, gave 3-O-methyl-DL-glucose (7). The same intermediate, 6, along with the methyl glycoside 8, could be obtained by the acid-catalyzed reaction of 3 with methanol. Lithium aluminum hydride reacted with 3 to form 1,6-anhydro-3-deoxy-β-DL-ribo-hexopyranose (9), which was hydrolyzed readily to 3-deoxy-DL-ribo-hexopyranose (10).Yields were excellent throughout. All products obtained from the oxirane 3 were those resulting only from trans diaxial opening of the oxirane ring.

Sign in / Sign up

Export Citation Format

Share Document