Serine Ester Research Articles

Reactions in frozen systems: VI. Ice as a possible model for biological structured-water systems

Rates were measured for the reaction of the following compounds with hydroxylamine in liquid and frozen aqueous solutions: cytosine, acetylcholine, glutamine, asparagine, 2,5-diketopiperazine, and esters of glycine, serine, tyrosine, phenylalanine, and glutamic acid. The observed first-order rate constants for reactions in ice ( −11 °, −18 °, −23 °) were generally higher than those for 1 ° and were higher than extrapolated values calculated from the Arrhenius equation. Altering the concentrations of hydroxylamine, dioxane, CuCl 2, KCl, Zn(NO 3) 2, imidazole, and pyrazole produced distinctive effects in reaction rates in bulk water and ice. The results are viewed as providing additional evidence for catalytic participation by ice structures. It is suggested that structured water in biopolymers and biological lamellar systems may similarly function catalytically.

The synthesis of 2-carboxy-6-nitrobenzimidazole 1-oxides by intramolecular oxidation of α-(2,4-dinitrophenylamino)-αβ-unsaturated acyl derivatives

In basic solutions of α-(2,4-dinitrophenylamino)αβ-unsaturated acyl derivatives, a 2-nitro-group intramolecularly oxidizes the β-position of the unsaturated acyl chain. Retroaldol cleavage of the oxygenated β-carbon occurs with ring closure of the scission product yielding an aldehyde and a 2-carboxy-6-nitrobenzimidazole 1-oxide (65–75%). This reaction occurs for the methyl ester of α-(2,4-dinitrophenylamino)acrylic acid and its β-substituted anologues, α-(2,4-dinitrophenylamino)crotonate and α-(2,4-dinitrophenylamino)cinnamate, in that respective order of reactivity, as well as the propyl amide of α-(2,4-dinitrophenylamino)acrylic acid. These reactions occur in protic and aprotic solvents with a large number of bases, and a tentative concerted mechanism is proposed. Reaction of N-2,4-dinitrophenylglycine methyl ester with base gives a moderate yield (50–60%) of 2-carboxy-6-nitrobenzimidazole 1-oxide as above. The N-2,4-dinitrophenyl methyl esters of serine, threonine, and β-phenylserine undergo retroaldol scission in base to the corresponding aldehyde and N-2,4-dinitrophenylglycine methyl ester, which quickly undergoes this same ring closure. This reaction occurs with sodium carbonate in methanol but not in dimethylformamide, and in contrast to the intramolecular oxidation is analogous to known base-catalyzed heterocyclic ring closure condensations of active methylene compounds with aromatic nitro-groups. The ring closures of N2,4-dinitrophenylamino-acid derivatives are suggested as reactions possibly useful in N-terminal amino-acid determination of peptides or glycoproteins.

Some New Esters of Serine with Various Acids1

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSome New Esters of Serine with Various Acids1Horace A. DeWald, D. Craig Behn, Marcus S. Morgan, Alice G. Renfrew, and Alexander M. MooreCite this: J. Am. Chem. Soc. 1959, 81, 16, 4367–4370Publication Date (Print):August 1, 1959Publication History Published online1 May 2002Published inissue 1 August 1959https://doi.org/10.1021/ja01525a067RIGHTS & PERMISSIONSArticle Views113Altmetric-Citations5LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (523 KB) Get e-Alerts Get e-Alerts

マグロ筋肉の脂質-V

The phosphoaminolipids obtained from cephalins of the muscle of a tuna, Thynnus orientalis, were converted to their dinitrophenyl (DNP) derivatives and applied to the chromatographic separation with a silicic acid/celite (2:1) column and chloroform/methanol to yield a DNP-ethanolamine-containing lipid (I), and amino acid-containing lipids (II), which gave a DNP-serine-containing lipid (II-a) and a mixture of DNP-serine-containing and DNP-threonine-containing lipids (II-b) by rechromatography. Hydrolysis of I with hydrochloric acid yielded DNP-ethanolamine, which gave free ethanolamine by decomposing with concentrated ammonium hydroxide. DNP-serine and-threonine, and free serine and threonine were isolated and identified with the same manner from II-a and II-b respectively. Periodate oxidation of the threonine fraction obtained from DNP-threonine of II-b gave acetaldehyde and glyoxylic acid. Component fatty acids of each fraction were found to be palmitic and oleic acids by paper chromatography. The presence of palmitoyloleoylglycerylphosphoryl esters of ethanolamine, serine and threonine can be supposed.

Copper(II), Nickel and Uranyl Complexes of Some Amino Acids1

The formation constants of copper(II) and nickel complexes of hydroxyproline, asparagine and N,Ndimethylglycine have been obtained. The pK2 of asparagine and the formation constants of its complexes are independeut of the optical configanration. The nickel complexes of serine methyl ester and glycine methyl ester are equally stable, indicating that the serine ester coordinates to the metal ion through the amino group only. At pH 1.90, uranyl ion forms a 1: 1 complex with glycine. In the pH region 3.0 to 4.3, the uranyl ion does not complex with glycine, hydroxyproline, asparagine, N,N- dimethylglycine and serine; only hydrolysis of the uranyl ion occurs.

602. A new synthesis of phosphatidylserine and the preparation of serine and 2-aminoethyl (“ethanolamine”) phosphate esters

602. A new synthesis of phosphatidylserine and the preparation of serine and 2-aminoethyl (“ethanolamine”) phosphate esters