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.

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 the Simple Peptide Model Ac-Abu(PO3H2)-NHMe

1992 ◽  
Vol 45 (4) ◽  
pp. 777 ◽  
Author(s):  
RM Valerio ◽  
JW Perich ◽  
PF Alewood ◽  
G Tong ◽  
RB Johns
Keyword(s):  
Acetic Acid ◽  
Simple Model ◽  
Acid Derivative ◽  
Peptide Synthesis ◽  
Solution Phase ◽  
Quantitative Yield ◽  
Initial Reaction ◽  
Mixed Anhydride ◽  
Butanoic Acid ◽  
Acid Cleavage

The simple model substrate AC-L-Abu(PO3H2)- NHMe was prepared by the use of the protected 4( diethylphosphono ) butanoic acid derivative Boc -Abu(PO3Et2)-OH in the Boc mode of solution phase peptide synthesis. The protected peptide model Ac-Abu(P03Et2)- NHMe was prepared by initial reaction of the isobutoxycarbonyl mixed anhydride of Boc-Abu(PO3Et2)-OH with N-methylamine followed by cleavage of the Boc group from Boc -Abu(PO3Et2)- NHMe with 4 M HCl/dioxan and N- acetylation of H-Abu(PO3Et2)-NHMe.HCl with the isobutoxycarbonyl mixed anhydride of acetic acid. Cleavage of the phosphonate ethyl groups was effected with 33% hydrogen bromidelacetic acid or 10% bromotrimethylsilane/acetonitrile to give AC-L-Abu(PO3H2)-NHMe in near-quantitative yield.

The use of 2,4,6-trimethylbenzyl esters in peptide synthesis

1966 ◽  
Vol 19 (6) ◽  
pp. 1067 ◽  
Author(s):  
FHC Stewart
Keyword(s):  
Acetic Acid ◽  
Hydrogen Chloride ◽  
Peptide Synthesis ◽  
Hydrogen Bromide ◽  
Ester Group ◽  
Protecting Groups ◽  
Reaction Conditions ◽  
Model Experiments ◽  
Benzyl Esters

Model experiments with the 2,4,6-trimethylbenzyl esters of N-acylamino acids have shown that this ester group is cleaved by hydrogen bromide in acetic acid under reaction conditions which do not affect benzyl esters appreciably, but which result in removal of benzyloxycarbonyl amino-protecting groups. 2,4,6-Trimethyl- benzyl esters, however, are unaffected by methanolic hydrogen chloride under the conditions used to cleave o-nitrophenylsulphenyl and trityl protecting groups. These selective differences have been utilized for the synthesis of various benzyloxycarbonyl peptide 2,4,6-trimethylbenzyl esters up to the hexapeptide level. Some of these derivatives have been converted into the corresponding free peptides by the action of hydrogen bromide in acetic acid. The 2,4,6-trimethylbenzyl group is more readily cleaved by hydrogen bromide than p-nitrobenzyloxycarbonyl and the possible application of this situation to peptide synthesis is considered.

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.

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.

scholarly journals Application of an Automated Synthesis Suite to Parallel Solution-Phase Peptide Synthesis.

2001 ◽  
Vol 49 (9) ◽  
pp. 1147-1154 ◽  
Author(s):  
Noritaka KURODA ◽  
Taeko HATTORI ◽  
Yoko FUJIOKA ◽  
David G. CORK ◽  
Chieko KITADA ◽  
...  
Keyword(s):  
Peptide Synthesis ◽  
Solution Phase ◽  
Automated Synthesis ◽  
Parallel Solution

scholarly journals Valorization of secondary feedstocks from the agroindustry by selective catalytic oxidation to formic and acetic acid using the OxFA process

2021 ◽  
Author(s):  
Sebastian Ponce ◽  
Stefanie Wesinger ◽  
Daniela Ona ◽  
Daniela Almeida Streitwieser ◽  
Jakob Albert
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Reaction System ◽  
Value Added ◽  
Industrial Wastes ◽  
Raw Material ◽  
Gaseous Oxygen ◽  
Water As Solvent ◽  
Selective Catalytic Oxidation ◽  
Major Interest

AbstractThe selective oxidative conversion of seven representative fully characterized biomasses recovered as secondary feedstocks from the agroindustry is reported. The reaction system, known as the “OxFA process,” involves a homogeneous polyoxometalate catalyst (H8PV5Mo7O40), gaseous oxygen, p-toluene sulfonic acid, and water as solvent. It took place at 20 bar and 90 °C and transformed agro-industrial wastes, such as coffee husks, cocoa husks, palm rachis, fiber and nuts, sugarcane bagasse, and rice husks into biogenic formic acid, acetic acid, and CO2 as sole products. Even though all samples were transformed; remarkably, the reaction obtains up to 64, and 55% combined yield of formic and acetic acid for coffee and cocoa husks as raw material within 24 h, respectively. In addition to the role of the catalysts and additive for promoting the reaction, the influence of biomass components (hemicellulose, cellulose and lignin) into biogenic formic acid formation has been also demonstrated. Thus, these results are of major interest for the application of novel oxidation techniques under real recovered biomass for producing value-added products. Graphical abstract

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