Fibrinogen-Induced Polymerization Via the Process of Methylation

1979 ◽  
Vol 42 (05) ◽  
pp. 1398-1410
Author(s):  
A J Osbahr
Keyword(s):  
Carboxylic Acid ◽  
Thionyl Chloride ◽  
Acid Group ◽  
Fibrin Clot ◽  
Spectrophotometric Analysis ◽  
The Other ◽  
Amino Group ◽  
Methyl Sulfate ◽  
Carboxylic Acid Groups ◽  
Other Hand

SummaryFibrinogen is polymerized by a number of group specific reagents including diazomethane, thionyl chloride and di-methyl sulfate at pH 7.4. The relationship between the number of methyl groups incorporated into fibrinogen and the extent of polymerization was evaluated. With diazomethane and thionyl chloride as modifying agents, polymerization ensued in approximately IV2 hr with extensive modification of fibrinogen. On the other hand, m�thylation via di-methyl sulfate-induced polymer formation occurs in approximately 35 min with primarily carboxylic acid group esterification. The polymerized fibrinogen formed under these conditions exhibited properties that were closely similar with the physiological fibrin clot.Amino group determinations revealed the m�thylation of amino acid residues other than the expected esterification of carboxylic acid groups. Diazomethane induced both N- methylation of lysine, as well as O-methylation of tyrosine, as estimated from spectrophotometric analysis. On the other hand, thionyl chloride modified only a small number of amino groups, and di-methyl sulfate modification resulted in no significant amounts of amino group methylation during the process of modification induced polymerization of fibrinogen.The profile of the number of methoxyl groups incorporated into fibrinogen with time for diazomethane modification may reflect a conformational change in the protein due to a more nonspecific m�thylation. Both the reagent and the conditions of modification were found to be important in achieving a selective modification of fibrinogen.A possible interpretation of these results is the esterification of carboxylic acid groups in the fibrinogen with reduction in the prevailing carboxylate ion negative repulsion, thereby achieving an increased protein-protein interaction with a resulting polymerization.

scholarly journals Crystal structure of betulinic acid methanol monosolvate

2014 ◽  
Vol 70 (12) ◽  
pp. o1242-o1243 ◽  
Author(s):  
Wei Tang ◽  
Neng-Hua Chen ◽  
Guo-Qiang Li ◽  
Guo-Cai Wang ◽  
Yao-Lan Li
Keyword(s):  
Carboxylic Acid ◽  
Solvent Molecule ◽  
Acid Group ◽  
Carboxylic Acid Group ◽  
Syzygium Jambos ◽  
Carboxylic Acid Groups ◽  
Pentacyclic Triterpenoid ◽  
Naturally Occurring ◽  
Dimensional Network ◽  
Chinese Medicinal Plant

The title compound [systematic name: 3β-hydroxylup-20(29)-en-28-oic acid methanol monosolvate], C30H48O3·CH3OH, is a solvent pseudopolymorph of a naturally occurring plant-derived lupane-type pentacyclic triterpenoid, which was isolated from the traditional Chinese medicinal plantSyzygium jambos(L.) Alston. The dihedral angle between the planes of the carboxylic acid group and the olefinic group is 12.17 (18)°. TheA/B,B/C,C/DandD/Ering junctions are alltrans-fused. In the crystal, O—H...O hydrogen bonds involving the hydroxy and carboxylic acid groups and the methanol solvent molecule give rise to a two-dimensional network structure lying parallel to (001).

scholarly journals Crystal structure of 4-(3-carboxypropanamido)-2-hydroxybenzoic acid monohydrate

2014 ◽  
Vol 70 (12) ◽  
pp. o1254-o1255 ◽  
Author(s):  
Muhammad Nawaz Tahir ◽  
Muhammad Naeem Ahmed ◽  
Arshad Farooq Butt ◽  
Hazoor Ahmad Shad
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Carboxylic Acid ◽  
Water Molecule ◽  
Organic Molecule ◽  
Three Dimensional ◽  
Acid Group ◽  
The Other ◽  
Hydroxybenzoic Acid ◽  
Dimensional Network

In the title hydrate, C11H11NO6·H2O, the organic molecule is approximately planar (r.m.s. deviation for the non-H atoms = 0.129 Å) and an intramolecular O—H...O hydrogen bond closes anS(6) ring. In the crystal, the benzoic acid group participates in an O—H...O hydrogen bond to the water molecule and accepts a similar bond from another water molecule. The other –CO2H group forms a carboxylic acid inversion dimer, thereby forming anR22(8) loop. These bonds, along with N—H...O and C—H...O interactions, generate a three-dimensional network.

scholarly journals Ozone-driven photochemical formation of carboxylic acid groups from alkane groups

2011 ◽  
Vol 11 (3) ◽  
pp. 7189-7233 ◽  
Author(s):  
S. Liu ◽  
D. A. Day ◽  
J. E. Shields ◽  
L. M. Russell
Keyword(s):  
Carboxylic Acid ◽  
Gas Phase ◽  
Formation Mechanism ◽  
Coastal Region ◽  
Chemical Properties ◽  
Acid Group ◽  
Acid Formation ◽  
Oh Radicals ◽  
Diurnal Cycles ◽  
Carboxylic Acid Groups

Abstract. Carboxylic acids are ubiquitous in atmospheric particles, and they play an important role in the physical and chemical properties of aerosol particles. During measurements in coastal California in the summer of 2009, carboxylic acid functional groups were highly associated with trajectories from an industrial region with high organic mass (OM), likely from fossil fuel combustion emissions. The concentration of carboxylic acid groups peaked during daytime, suggesting a photochemical secondary formation mechanism. This daytime increase in concentration was tightly correlated with O3 mixing ratio, indicating O3 was the likely driver in acid formation. Based on the diurnal cycles of carboxylic acid and alkane groups, the covariation of carboxylic acid groups with O3, and the composition of the Combustion factor resulted from the factor analyses, gas-phase alkane oxidation by OH radicals to form dihyfrofuran followed by further oxidation of dihydrofuran by O3 is the likely acid formation mechanism. Using the multi-day average of the daytime increase of carboxylic acid group concentrations and m/z 44-based Aged Combustion factor, we estimated the lower-bound contributions of secondary organic aerosol (SOA) formed in 12-h daytime of processing in a single day to be 30% of the carboxylic acid groups and 25–45% of the Combustion factor concentration. These unique ambient observations of photochemically-driven acid formation suggest that gas-phase alkanes might be important sources of SOA formation in this coastal region.

scholarly journals Spectroscopy Study of Honey Pineapple Peels Extracted in Different Solvents

2021 ◽  
Vol 3 (1) ◽  
pp. 32-35
Author(s):  
Yehezkiel Steven Kurniawan ◽  
Edi Setiyono ◽  
Marcelinus Alfasisurya Setya Adhiwibawa ◽  
Krisfian Tata Aneka Priyangga ◽  
Leny Yuliati
Keyword(s):  
Carboxylic Acid ◽  
Visible Region ◽  
Water Extract ◽  
Ethanolic Extract ◽  
Acetone Extract ◽  
The Other ◽  
Distilled Water ◽  
Spectroscopy Study ◽  
Absorption Signal ◽  
Other Hand

In the present work, we investigated the extract of honey pineapple peels in distilled water, ethanol, and acetone solvents. The spectroscopy study of each extract was performed using a Fourier transform infrared (FTIR) spectrometer, an ultraviolet-visible (UV-Vis) spectrophotometer, and a spectrofluorometer. The FTIR spectrum of the distilled water extract indicated that the distilled water extract may contain alcohol or carboxylic acid compounds. Meanwhile, the ethanolic extract may contain alcohol or carboxylic acid, or ether compounds. On the other hand, the acetone extract may contain alcohol or ether or aromatic or aliphatic compounds. The UV-Vis spectrum of the honey pineapple peels extracted in the distilled water, ethanol, and acetone showed a broad absorption signal at UV region (< 300 nm), four absorption signals at UV region (232-368 nm), and four absorption signals at UV region (231-368 nm) with a weak absorption signal at the visible region at 559 nm, respectively. The distilled water and acetone extracts gave fluorescence signals, however, the ethanolic extract showed no fluorescence intensity. From the FTIR, UV-Vis, and fluorescence spectra characterization, the extracted natural pigments from the honey pineapple peels in distilled water, ethanol, and acetone solvents were identified. The distilled water extract may contain polar flavonoid or steroid compounds while the ethanolic extract may contain polar carotenoid pigments. On the other hand, the acetone extract may contain carotenoid and chlorophyll pigments as shown by an emission signal at 670 nm.

Embryonic Responses to Structurally Related Inhibitors

Development ◽  
1960 ◽  
Vol 8 (4) ◽  
pp. 445-456
Author(s):  
Kathe Liedke ◽  
H. B. Gillespie ◽  
Samuel Graff
Keyword(s):  
Nitro Group ◽  
Rana Pipiens ◽  
The Other ◽  
Amino Group ◽  
Inhibitory Effects ◽  
Tail Bud ◽  
Cytotoxic Effects ◽  
Other Hand

Substituted benzotriazoles (Bt) have been shown to bring about interesting inhibitory effects on Rana pipiens embryos of 2-cell to tail-bud stages (Liedke, Engelman, & Graff, 1954, 1955, 1957a, 1957b). These benzotriazoles did not have selective cytotoxic effects on sensitive embryonic structures as similarly substituted benzimidazoles (Bz) and quinoxalines (Q) invariably did. The latter compounds, Bz and Q, were most active against younger stages, especially those in cleavage. On the other hand, it was found that the susceptibility to the benzotriazoles increased with age of embryo; more differentiated stages were affected most. The type of response was determined by the parent structure, but certain substituents, the nitro group in particular, appeared to enhance the magnitude of the effect. The activating effect of the nitro group was in turn modified to varying degree by an accompanying methoxy, hydroxy, or amino group.

Alkylation by secondary alcohols. I. The reaction of xanthydrol with some N1-monosubstituted sulfanilamides and related compounds

1967 ◽  
Vol 45 (13) ◽  
pp. 1411-1424 ◽  
Author(s):  
R. E. Moskalyk ◽  
L. G. Chatten
Keyword(s):  
Nitrogen Atom ◽  
Tautomeric Form ◽  
Heterocyclic Ring ◽  
The Other ◽  
Secondary Alcohols ◽  
Amino Group ◽  
Aromatic Character ◽  
Carbonium Ion ◽  
Other Hand ◽  
Related Compounds

Sulfanilamides were found to undergo alkylation with xanthydrol, yielding either mono- or di-xanthenyl derivatives. The site of substitution, common to all sulfanilamides having a free p-amino group, was shown to be the N4-position in the sulfanilamide molecule. Three additional unique reactive sites were observed. Sulfanilamides carrying a thiazole, thiadiazole, or pyridazine substituent in the N1-position were also alkylated on the annular nitrogen atom of the heterocyclic ring, the reaction having occurred from the imido tautomeric form. Sulfisoxazole (IK), on the other hand, reacted from the amido form to give the N1,N4-dixanthenyl derivative. Sulfadimethoxine (Ih) was substituted at carbon, as well as at nitrogen, to yield N4-xanthenyl-N1-(2,6-dimethoxy-5-(9-xanthenyl)-4-pyrimidyl)sulfanilamide.Sulfanilamides possessing pKa values of about 5.5 were found to be sufficiently acidic to catalyze their own reaction with xanthydrol, and no external catalyst was necessary. The exceptional ease of formation of the xanthylium ion was postulated to be associated with the resulting stability of this carbonium ion by virtue of its acquired aromatic character.

scholarly journals Characterization of autohydrolysis aspen (P. tremuloides) lignins. Part 3. Infrared and ultraviolet studies of extracted autohydrolysis lignin

1979 ◽  
Vol 57 (19) ◽  
pp. 2603-2611 ◽  
Author(s):  
Miranda G. S. Chua ◽  
Morris Wayman
Keyword(s):  
Carboxylic Acid ◽  
Blocking Agent ◽  
Acid Group ◽  
Hydroxybenzoic Acid ◽  
Aspen Wood ◽  
Carboxylic Acid Group ◽  
Carboxylic Acid Groups ◽  
Acidic Conditions ◽  
Lignin Macromolecule

Infrared and ultraviolet studies of the lignins extracted from extractive-free aspen wood meal after autohydrolysis at 195 °C for periods varying from 5 min to 2 h indicated that these lignins were functionally modified and different from aspen milled wood lignin. The extracted lignins changed from a guaiacyl–syringyl type lignin to a syringyl-deficient type lignin with increasing autohydrolysis time. Extracted lignins were also observed to contain unconjugated β-ketone groups and conjugated carboxylic acid groups. It is proposed that the unconjugated β-ketone groups resulted from the depolymerization reactions of the lignin macromolecule under acidic conditions which formed monomeric, dimeric, and oligomeric/polymeric lignin fragments with Hibbert's ketone side chains. The conjugated carboxylic acid group observed to be present was attributed to p-hydroxybenzoic acid. p-Hydroxybenzoic acid has been postulated as contributing to the extractability of aspen lignin by acting as a blocking agent in the repolymerization of lignin fragments to form insoluble lignin.

Transformation of 1,2-Dithiole-3-thiones Into 1,6,6aλ4-Trithiapentalenes via Reaction with Bromoethanones

2006 ◽  
Vol 71 (5) ◽  
pp. 650-666 ◽  
Author(s):  
Richard Čmelík ◽  
Pavel Pazdera
Keyword(s):  
Carboxylic Acid ◽  
Thionyl Chloride ◽  
Reaction Mechanisms ◽  
Amino Group ◽  
Inverted Order ◽  
Derivatives Of

We report the reactions of derivatives of 5-amino-3-thioxo-3H-1,2-dithiole-4-carboxylic acid 1 with bromoethanones and acylation agents. Two different routes were used to obtain the products, 3-(acylmethylidene)-3H-1,2-dithioles 4. These compounds were synthesized by acylation of compounds 1 on the amino group, followed by the reaction with bromoethanones and excess of triethylamine. Another method was based on the inverted order of the mentioned reaction steps and in absence of a base. The treatment of 4 with thionyl chloride gave new unsaturated fused lactones 13 whereas thionation led to desired 1,6,6aλ4-trithiapentalenes 5. The structures of products and the reaction mechanisms are discussed.

Transient nitronic acid formation in the protonation of the carbanion of 2,2′,4,4′-tetranitrodiphenylmethane in acidic methanol

1987 ◽  
Vol 65 (8) ◽  
pp. 1980-1986 ◽  
Author(s):  
François Terrier ◽  
Jacques Lelièvre ◽  
Alain-Pierre Chatrousse ◽  
Robert Schaal ◽  
Patrick G. Farrell
Keyword(s):  
Carboxylic Acid ◽  
Solvent Effects ◽  
Rate Constants ◽  
Intrinsic Rate ◽  
Low Ph ◽  
The Other ◽  
Acid Formation ◽  
Other Hand ◽  
Protonated Species ◽  
Nitronic Acid

Rates of deprotonation of 2,2′,4,4′-tetranitrodiphenylmethane (1) by a variety of bases B− and of protonation of the resulting carbanion (2) by the conjugated acids BH in methanol have been measured at 20 °C. The Brønsted αBH coefficients for protonation of 2 by phenol and carboxylic acid buffers are equal to 0.58 and 0.43, respectively, as compared with αBH values of 0.59 and 0.52 respectively, for the same reactions in 50% H2O – 50% DMSO. On the other hand, a comparison of the intrinsic rate constants [Formula: see text] (in the Marcus sense) in the two solvents reveals that the effect of going from 50% H2O – 50% DMSO to methanol is to lower [Formula: see text] for the phenol reactions by a factor of 2 but to increase [Formula: see text]for carboxylic acid reactions by a factor of 5. It is shown that the solvent effects on αBH and [Formula: see text] can all be understood in the context of the Principle of Imperfect Synchronisation (PIS) recently proposed by Bernasconi. In addition, a fast equilibrium protonation of the carbanion 2 is found to precede its conversion to 1 at low pH, i.e., pH < 5. The resulting protonated species is suggested to be the nitronic acid 2,H arising from fast protonation of a para NO2 group of 2. The [Formula: see text] value associated with the ionization of 2,H is ∼4.25.

Über die Umsetzung von Benzylmalonylchlorid mit verschiedenen Natriumsalzen von Carbonsäuren / The Reaction of Benzylmalonyl Chloride with Sodium Salts of Carboxylic Acids

1972 ◽  
Vol 27 (5) ◽  
pp. 528-530 ◽  
Author(s):  
Helga Wittmann ◽  
Helmut Rathmayr
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Acid Chloride ◽  
Sodium Benzoate ◽  
Sodium Acetate ◽  
The Other ◽  
Carboxylic Acid Chloride ◽  
Sodium Salts ◽  
Other Hand ◽  
Sodium Phenylacetate

Benzylmalonyl Chloride reacts in the presence of sodium acetate in boiling benzene to give tribenzyl-phloroglucinol-triacetate, however with sodium chloroacetate to 3,5-dibenzyl-6-phenethylpyran-2,4-dion. In both cases trimerisation of benzylketene or benzylketene carboxylic acid chloride occurs. On the other hand, benzylmalonylchloride reacts with sodium benzoate and sodium phenylacetate via a dimeric benzylketene carboxylic acid chloride under the loss of phosgene to yield cyclopentadienyl derivatives.

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