Synthesis of Casein-Related Peptides and Phosphopeptides. X. A Modified Method for the Synthesis of Ser(P)-Containing Peptides Through 4-Bromobenzyl Phosphate Protection

1991 ◽  
Vol 44 (3) ◽  
pp. 389 ◽  
Author(s):  
JW Perich ◽  
RB Johns
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Peptide Synthesis ◽  
Acid Solutions ◽  
Isobutyl Alcohol ◽  
Modified Method ◽  
Step Procedure ◽  
One Step ◽  
Phosphate Protection

The three 4-halobenzyl phosphoramidite reagents di (4-fluorobenzyl) N,N- diisopropylphosphor-amidite, di (4-chlorobenzyl) N,N- diisopropylphosphoramidite and di (4-bromobenzyl) N,N-diethylphosphoramidite were prepared and used for the efficient phosphite-triester phosphorylation of isobutyl alcohol. While all three 4-halobenzyl groups were cleaved at similar rates from the 4-halobenzyl phosphorotriesters by 4 M HCl/dioxan or 50% CF3CO2H/CH2Cl2, the 4-bromobenzyl group had greater stability than either the 4-fluorobenzyl or 4-chlorobenzyl groups in formic acid or 1 M HCl /acetic acid solutions. The protected 4-bromobenzyl derivative, Boc-Ser(PO3BrBzl2)-OH, was prepared by a novel one-step procedure which featured di-4-bromobenzyl N,N- diethylphosphoramidite as phosphitylating agent. This derivative was used for the synthesis of Boc-Glu ( OBzl )-Ser(PO3BrBzl2)- Leu-OBzl by the Boc mode of peptide synthesis with 98% formic acid being used for the cleavage of the Boc group. Palladium-catalysed hydrogenolysis of the protected Ser(PO3BrBzl2) tripeptide in formic acid gave zwitterionic Glu -Ser(P)-Leu in high overall yield.

Synthesis of Casein-Related Peptides and Phosphopeptides. IX. A Modified Method for the Synthesis of Ser(P) Peptides by Using Ppoc-Ser(PO3bzl2)-OH

1991 ◽  
Vol 44 (3) ◽  
pp. 377 ◽  
Author(s):  
JW Perich ◽  
PF Alewood ◽  
RB Johns
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Hydrogen Chloride ◽  
Peptide Synthesis ◽  
Stability Study ◽  
Solution Phase ◽  
Alternative Procedure ◽  
Modified Method ◽  
Step Procedure ◽  
Phosphate Groups

Benzyl phosphate groups were found to be sensitive to acid conditions, and a stability study with dibenzyl isobutyl phosphate under various acid conditions is described. While extensive acidolytic debenzylation of the dibenzyl phosphorotriester occurred on treatment with either 4 M hydrogen chloride/ dioxan or 50% trifluoroacetic acid/dichloromethane, only minor benzyl loss occurred with the use of formic acid or 1 M hydrogen chloride/acetic acid. Minimization of benzyl phosphate loss during the synthesis of a Ser(PO3Bzl2)-containing tripeptide was effected by the use of 98% formic acid (or 1 M hydrogen chloride/acetic acid) for the cleavage of the Boc group from Boc -Ser(PO3Bzl2)- Leu-OBzl . In an alternative procedure, the protected 2-phenylisopropyloxycarbonyl derivative, Ppoc -Ser(PO3Bzl2)-OH was prepared by an efficient four-step procedure and was used in a solution-phase peptide synthesis for the high yielding preparation of Boc-Glu ( OBzl )-Ser(PO3Bzl2)- Leu-OBzl . The protected Ser(PO3Bzl2) tripeptide was deprotected by palladium- catalysed hydrogenolysis in formic acid and gave Glu -Ser(P)-Leu in near-quantitative yield.

Steroid and bile acids amide conjugates with D-glucosamine

2011 ◽  
Vol 76 (1) ◽  
pp. 65-74
Author(s):  
Zdena Nováková ◽  
Jana Tomanová ◽  
Lucie Štěrbová ◽  
Pavel Drašar
Keyword(s):  
Acetic Acid ◽  
Bile Acids ◽  
Acid Chloride ◽  
Acetyl Chloride ◽  
Glucosamine Hydrochloride ◽  
Negative Results ◽  
Step Procedure ◽  
One Step ◽  
New Type

New type of amide conjugates of steroid and bile acids with D-glucosamine 1 and 2 were prepared. Title compounds are prepared via acid chloride or using N-[({[(1E)-1-cyano-2-ethoxy-2-oxoethylidene]amino}oxy)(dimethylamino)methylidene]-N-methylmethanaminium tetrafluoroborate as condensation agent. They were examined for gelation properties with negative results. Per-O-acetylated D-glucosamine hydrochloride was prepared in one step procedure from D-glucosamine hydrochloride by acetylation in a mixture of acetyl chloride and acetic acid.

Hydrophobic hydration in aqueous acetic acid and formic acid solutions probed by high pressure

2002 ◽  
Vol 98 (1-4) ◽  
pp. 177-182 ◽  
Author(s):  
Ming-Shan Lin ◽  
Chun-Min Feng ◽  
Hsiang-En Kao ◽  
Yu-Chun Huang ◽  
Hai-Chou Chang ◽  
...  
Keyword(s):  
High Pressure ◽  
Acetic Acid ◽  
Formic Acid ◽  
Hydrophobic Hydration ◽  
Aqueous Acetic Acid ◽  
Acid Solutions

NON-SUPPRESSIBLE INSULIN-LIKE ACTIVITY AND SULPHATION ACTIVITY IN SERUM EXTRACTS OF NORMAL SUBJECTS, ACROMEGALICS AND PITUITARY DWARFS

1976 ◽  
Vol 81 (1) ◽  
pp. 28-42 ◽  
Author(s):  
U. Schlumpf ◽  
R. Heimann ◽  
J. Zapf ◽  
E. R. Froesch
Keyword(s):  
Molecular Weight ◽  
Growth Hormone ◽  
Acetic Acid ◽  
Large Scale ◽  
Normal Subjects ◽  
Step Procedure ◽  
Chromatographic Procedure ◽  
One Step ◽  
Insulin Like Activity

ABSTRACT Non-suppressible insulin-like activity (NSILA) is a term used for a variety of substances in serum, excluding insulin, which promote glucose uptake of adipose tissue and diaphragm in vitro. NSILA-S is a peptide with a molecular weight of 7000 which is soluble in acid ethanol and which has been purified on a large scale from human serum. This study describes a simple chromatographic one step procedure by which NSILA-S can be extracted and quantitatively measured in individual sera. Using Sephadex G-75 equilibrated with 1 m acetic acid, NSILA-S was detected only in one peak containing small molecular peptides. NSILA-S obtained with this one step chromatographic procedure exerted all the effects of purified NSILA-S including sulphation activity on the rat cartilage. All chromatographic fractions with NSILA-S also had sulphation activity. Both, NSILA-S and sulphation activity were increased in acromegalics and decreased in pituitary dwarfs. It is suggested that one molecule in serum is responsible for both activities which are, at least in part, under the control of growth hormone.

scholarly journals Electrochromic Performance and Capacitor Performance of α-MoO3 Nanorods Fabricated by a One-Step Procedure

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 783
Author(s):  
Ying Duan ◽  
Chen Wang ◽  
Jian Hao ◽  
Yang Jiao ◽  
Yanchao Xu ◽  
...  
Keyword(s):  
Growth Parameters ◽  
Average Diameter ◽  
Fast Response ◽  
Cycle Stability ◽  
Electrochromic Devices ◽  
Step Procedure ◽  
One Step ◽  
Supercapacitor Performance ◽  
First Time ◽  
Prepared Nanorods

In this paper, we propose for the first time the synthesis of α-MoO3 nanorods in a one-step procedure at mild temperatures. By changing the growth parameters, the microstructure and controllable morphology of the resulting products can be customized. The average diameter of the as-prepared nanorods is about 200 nm. The electrochromic and capacitance properties of the synthesized products were studied. The results show that the electrochromic properties of α-MoO3 nanorods at 550 nm have 67% high transmission contrast, good cycle stability and fast response time. The MoO3 nanorods also exhibit a stable supercapacitor performance with 98.5% capacitance retention after 10,000 cycles. Although current density varies sequentially, the nanostructure always exhibits a stable capacitor to maintain 100%. These results indicate the as-prepared MoO3 nanorods may be good candidates for applications in electrochromic devices and supercapacitors.

Durability of Red Mud Based Geopolymer Paste in Acid Solutions

2016 ◽  
Vol 866 ◽  
pp. 99-105 ◽  
Author(s):  
Smita Singh ◽  
M.U. Aswath ◽  
R.V. Ranganath
Keyword(s):  
Mechanical Properties ◽  
Acetic Acid ◽  
Fly Ash ◽  
Red Mud ◽  
Acetic Acid Solution ◽  
Strength Loss ◽  
Acid Solutions ◽  
Test Results ◽  
Acid Attack ◽  
Geopolymer Paste

The present investigation is on the effect of red mud on the mechanical properties and durability of the geopolymer paste in sulphuric and acetic acid solution. Red mud and fly ash were used to form the geopolymer paste along with the alkalies. The variation of red mud in the paste composition was from 0% to 90%. Cylindrical shaped specimens of 1 inch diameter and 1 inch height were prepared. The specimens were immersed in 5% sulphuric acid and 5% acetic acid for 1, 7, 14, 28, 56 and 84 days and tested for weight loss, visual deformation, strength loss and colour of the solvent, based on the procedure specified by ASTM C 267 – 01. SEM/EDX Tests were performed on the geopolymer specimens. Test results show that initially, the strength of the geopolymer increased upon the addition of red mud. The strength was maximum when the percentage of red mud was 30%. The maximum strength obtained was 38 MPa for the paste containing 30% red mud using 10M alkali solution as against 31.69 MPa, when only fly ash was used. Geopolymer paste containing 30% and 50% red mud showed better resistance to acid attack. The strength loss was minimum for the samples containing 30% red mud in both inorganic and organic acid i.e. sulphuric and acetic acid.

Confirmatory Tests for Aflatoxin B1

1964 ◽  
Vol 47 (5) ◽  
pp. 801-803 ◽  
Author(s):  
Peter John Andrellos ◽  
George R Reid
Keyword(s):  
Acetic Acid ◽  
Thin Layer ◽  
Formic Acid ◽  
Thionyl Chloride ◽  
Aflatoxin B1 ◽  
Trifluoroacetic Acid ◽  
Reaction Products ◽  
Confirmatory Tests ◽  
Aflatoxin B ◽  
Layer Chromatography

Abstract Three confirmatory tests have been devised to identify aflatoxin B±. Portions of the isolated toxin are treated with formic acid-thionyl chloride, acetic acid-thionyl chloride, and trifluoroacetic acid, respectively, and aliquots of the three fluorescent reaction products are spotted on thin-layer chromatography plates. Standards treated with each of the three reagents, plus an untreated standard, are spotted on the same plate, and after development the spots are compared under ultraviolet light.

scholarly journals REGULATORY MECHANISMS OF CELLULAR RESPIRATION

1950 ◽  
Vol 34 (2) ◽  
pp. 211-224 ◽  
Author(s):  
E. S. Guzman Barron ◽  
Maria Isabel Ardao ◽  
Marion Hearon
Keyword(s):  
Acetic Acid ◽  
Pyruvic Acid ◽  
No Oxidation ◽  
Yeast Cells ◽  
Acid Formation ◽  
Cellular Respiration ◽  
Acid Oxidase ◽  
Acid Solutions ◽  
Fluoroacetic Acid ◽  
A Cell

The rate of the aerobic metabolism of pyruvic acid by bakers' yeast cells is determined mainly by the amount of undissociated acid present. As a consequence, the greatest rate of oxidation was observed at pH 2.8. Oxidation, at a slow rate, started at pH 1.08; at pH 9.4 there was no oxidation at all. The anaerobic metabolism, only a fraction of the aerobic, was observed only in acid solutions. There was none at pH values higher than 3. Pyruvic acid in the presence of oxygen was oxidized directly to acetic acid; in the absence of oxygen it was metabolized mainly by dismutation to lactic and acetic acids, and CO2. Acetic acid formation was demonstrated on oxidation of pyruvic acid at pH 1.91, and on addition of fluoroacetic acid. Succinic acid formation was shown by addition of malonic acid. These metabolic pathways in a cell so rich in carboxylase may be explained by the arrangement of enzymes within the cell, so that carboxylase is at the center, while pyruvic acid oxidase is located at the periphery. Succinic and citric acids were oxidized only in acid solutions up to pH 4. Malic and α-ketoglutaric acids were not oxidized, undoubtedly because of lack of penetration.

α-DEUTERIUM KINETIC ISOTOPE EFFECTS IN SOLVOLYSES OF endo-NORBORNYL p-BROMOBENZENESULFONATE

1965 ◽  
Vol 43 (8) ◽  
pp. 2254-2258 ◽  
Author(s):  
C. C. Lee ◽  
Edward W. C. Wong
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Aqueous Dioxane ◽  
Kinetic Isotope ◽  
Different Temperatures

endo-Norbornyl-2-d p-bromobenzenesulfonate was synthesized and the isotope effects, as measured by kH/kD, were determined over a range of temperatures for solvolyses in 30% water – 70% dioxane, acetic acid, and formic acid. Values of kH/kD are of the order of 1.20. The data appear to indicate slightly higher isotope effects as the solvents are changed from aqueous dioxane to acetic acid to formic acid, as well as somewhat higher isotope effects at lower temperatures. Possible mechanistic implications of these results are presented. Relative titrimetric acetolysis rates, kexo/kendo, at different temperatures, and enthalpies and entropies of activation for these acetolyses are evaluated and discussed.

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