Zwitterion ratios of aminobenzoic acids

1969 ◽  
Vol 22 (6) ◽  
pp. 1189 ◽  
Author(s):  
EP Serjeant
Keyword(s):  
Methyl Ester ◽  
Ethyl Ester ◽  
Ethyl Esters ◽  
Aminobenzoic Acid ◽  
Pka Values ◽  
Aminobenzoic Acids ◽  
Substituent Constants

Relations have been established between the pKa values for the non- zwitterionic forms of meta- and para-aminobenzoic acids, pKB, and the pKa values of the corresponding methyl and ethyl esters, pKE. For methyl m-aminobenzoate, the expression is pKB = pKE + 0.09, whilst for the ethyl ester it is pKB = pKE + 0.03. The corresponding relations for p- aminobenzoic acid derivatives are pKB = pKE + 0.06 for the methyl ester, and pKB = pKE + 0.03 for the ethyl ester. The mioroscopic constants pertaining to the zwitterionic equilibria are given, and are used to establish the Hammett substituent constants, σm, for the following meta substituent groups: NH2, 0.00; NH3+, 0.98; NHCH2COOEt, -0.10; COOH, 0.30; COOMe, 0.33; COOEt, 0.31; COO-, 0.01.

The Enzyme Catalysed Stereoselective Transesterification of Phenylalanine Derivatives in Supercritical Carbon Dioxide

2002 ◽  
Vol 55 (4) ◽  
pp. 259 ◽  
Author(s):  
A. J. Smallridge ◽  
Z. Wang ◽  
M. A. Trewhella
Keyword(s):  
Carbon Dioxide ◽  
Methyl Ester ◽  
Supercritical Carbon Dioxide ◽  
Ethyl Ester ◽  
Methyl Esters ◽  
Optimum Concentration ◽  
Ethyl Esters ◽  
Subtilisin Carlsberg ◽  
Phenylalanine Methyl Ester ◽  
Supercritical Carbon

The subtilisin Carlsberg catalysed transesterification of N-acetyl phenylalanine methyl ester (1), N-acetyl phenylalanine ethyl ester (2), N-trifluoroacetyl phenylalanine methyl ester (3) and N-trifluoroacetyl phenylalanine ethyl ester (4) was studied in supercritical carbon dioxide. The water content of the reaction affects the reactivity of the system; for the transesterification of the methyl esters with ethanol the optimum concentration of water was determined to be about 0.74 M, while for the transesterification of the ethyl esters with methanol the optimum concentration of water was about 1.3 M. The conversion is also dependent upon the concentration of alcohol; for ethanol, 2% v/v gives the maximum conversion, whilst for methanol, only 0.8-1.2% v/v is required. This is probably due to a difference in the solubility of the substrates in the two alcohol/supercritical carbon dioxide mixtures. The reaction is highly stereoselective, in all cases no evidence for reaction of the D-isomer could be detected by chiral gas chromatography.

scholarly journals Using SVM-RSM and ELM-RSM Approaches for Optimizing the Production Process of Methyl and Ethyl Esters

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2889 ◽  
Author(s):  
Sina Faizollahzadeh Ardabili ◽  
Bahman Najafi ◽  
Meysam Alizamir ◽  
Amir Mosavi ◽  
Shahaboddin Shamshirband ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Production Process ◽  
Ethyl Ester ◽  
Fuzzy Inference ◽  
Ethyl Esters ◽  
Production Yield ◽  
Molar Ratio ◽  
Support Vector ◽  
Inference System ◽  
Mixing Intensity

The production of a desired product needs an effective use of the experimental model. The present study proposes an extreme learning machine (ELM) and a support vector machine (SVM) integrated with the response surface methodology (RSM) to solve the complexity in optimization and prediction of the ethyl ester and methyl ester production process. The novel hybrid models of ELM-RSM and ELM-SVM are further used as a case study to estimate the yield of methyl and ethyl esters through a trans-esterification process from waste cooking oil (WCO) based on American Society for Testing and Materials (ASTM) standards. The results of the prediction phase were also compared with artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS), which were recently developed by the second author of this study. Based on the results, an ELM with a correlation coefficient of 0.9815 and 0.9863 for methyl and ethyl esters, respectively, had a high estimation capability compared with that for SVM, ANNs, and ANFIS. Accordingly, the maximum production yield was obtained in the case of using ELM-RSM of 96.86% for ethyl ester at a temperature of 68.48 °C, a catalyst value of 1.15 wt. %, mixing intensity of 650.07 rpm, and an alcohol to oil molar ratio (A/O) of 5.77; for methyl ester, the production yield was 98.46% at a temperature of 67.62 °C, a catalyst value of 1.1 wt. %, mixing intensity of 709.42 rpm, and an A/O of 6.09. Therefore, ELM-RSM increased the production yield by 3.6% for ethyl ester and 3.1% for methyl ester, compared with those for the experimental data.

scholarly journals Effect of 3-Aminobenzoic Acid Ethyl Ester Methanesulfonate (MS-222) on Quality of Marine Cultured Turbot (Scophthalmus maximus) during Simulated Transport in Water

Fishes ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 20
Author(s):  
Jie Cao ◽  
Qi Wang ◽  
Jun Mei ◽  
Jing Xie
Keyword(s):  
Dissolved Oxygen ◽  
Ethyl Ester ◽  
Acid Ethyl Ester ◽  
Scophthalmus Maximus ◽  
Ammonia Nitrogen ◽  
Control Group ◽  
Aminobenzoic Acid ◽  
Transport Stress ◽  
Turbot Scophthalmus Maximus

This study evaluated the effect of different concentrations (20, 40 and 60 mg/L) of 3-aminobenzoic acid ethyl ester methanesulfonate (MS-222) on the quality changes in turbot during simulated transport in water. The results showed that the ammonia nitrogen content in the transportation water of each sample increased significantly, and the dissolved oxygen level decreased. The dissolved oxygen content in MS-222-treated samples was higher than that of control group (CK) samples. For turbot flesh quality, simulated transport in water led to a decrease in moisture, fat and protein contents in all samples. The MS-222-treated turbot samples showed higher pH values, glycogen contents, springiness and chewiness values and lower lactic acid contents comparing with the CK samples during simulated transport in water. In addition, the fresh and bitter amino acids in the muscle of turbot increased in each treatment group compared to the non-transported fish at the end of the simulated transport. The results showed that MS-222 treatment could retard the turbot transport stress and improve the quality of turbot during simulated transport in water.

scholarly journals GC-MS ANALYSIS OF INVASIVE AQUATIC WEED, PISTIA STRATIOTES L. AND EICHHORNIA CRASSIPES (MART.) SOLMS

2017 ◽  
Vol 9 (3) ◽  
pp. 111 ◽  
Author(s):  
Tulika Tyagi ◽  
Mala Agarwal
Keyword(s):  
Methyl Ester ◽  
Ethyl Ester ◽  
Eichhornia Crassipes ◽  
Acid Methyl Ester ◽  
Acid Ethyl Ester ◽  
Pistia Stratiotes ◽  
Aquatic Weed ◽  
Hexadecenoic Acid ◽  
Hexadecanoic Acid ◽  
Acid Methyl

Objective: To investigate the bioactive components of an invasive aquatic weed, Pistia stratiotes L. and Eichhornia crassipes (Mart.) Solms vegetative parts by using Gas Chromatography-Mass Spectrometer (GC-MS).Methods: The chemical compositions of the ethanol extract of whole plant Pistia stratiotes L. and Eichhornia crassipes (Mart.) Solms was investigated using Agilent Technologies GC-MS (GC-7890A, MS 5975C).Results: The results of GC-MS analysis of the ethanolic extract revealed the existence of 28 phytochemical compounds in Pistia stratiotes L. n-Hexadecanoic acid,-11-Hexadecenoic acid, ethyl ester, Hexadecanoic acid, ethyl ester, Octadecanoic acid, ethyl ester, 2-Cyclopenten-1-one, 5-hydroxy-2,3-dimethyl, L-Glutamine, 2-Pentadecanone, 6,10,14-trimethyl, Linolelaidic acid, methyl ester, 9,12,15-Octadecatrienoic acid, methyl ester,(Z,Z,Z), Nonadecane, 12,15-Octadecadiynoic acid, methyl ester, Hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl)ethyl ester, Diisooctyl phthalate, Docosanoic acid, ethyl ester, Stigmasterol, Bis(2-ethylhexyl) phthalate, 1-Monolinoleoylglycerol trimethylsilyl ether, Ethyl iso-allocholate are the major compound.The ethanolic extract of Eichhornia crassipes (Mart.) Solms contains 43 phytochemical compounds of high and low molecular weight n-Hexadecanoic acid, E-11-Hexadecenoic acid, ethyl ester, Palmitic acid, Phytol, 9,12,15-Octadecatrienal, 9,12-Octadecadienoic acid, ethyl ester, Linolenic acid, ethyl ester, Stearic acid, ethyl ester, Hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl)ethyl ester, α-Glyceryl linolenate, 1-Monolinoleoylglycerol trimethylsilyl ether, Linoleic acid, 2,3-bis-(O-TMS)-propyl ester, Stigmasterol, Linolelaidic acid, methyl ester, 9,12,15-Octadecatrienoic acid, ethyl ester, (Z,Z,Z), Ethyl iso-allocholate, Cholesta-22,24-dien-5-ol, 4,4-dimethyl are the major compounds.These results indicates Pistia stratiotes L. and Eichhornia crassipes (Mart.) Solms possess potent antioxidant, anti-inflammatory, anticancer, antitumour, antiarthritic, cancer preventive, antibacterial effects so can be recommended as a plant of phytopharmaceutical importance.Conclusion: The ethanol extract of Pistia stratiotes L. and Eichhornia crassipes (Mart.) Solms proves as a potential source of bioactive compounds of pharmacological importance.

scholarly journals Bioactive Phenolic Compounds from the Roots of Danshen (Salvia miltiorrhiza)

2018 ◽  
Vol 13 (10) ◽  
pp. 1934578X1801301
Author(s):  
Nguyen Huu Tung ◽  
Le Quoc Hung ◽  
Ha Van Oanh ◽  
Duong Thi Ly Huong ◽  
Phuong Thien Thuong ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Methyl Ester ◽  
Ethyl Ester ◽  
Rosmarinic Acid ◽  
Salvia Miltiorrhiza ◽  
Chemical Constituents ◽  
Acid Methyl Ester ◽  
Acid Ethyl Ester ◽  
Salvianolic Acid ◽  
Salvianolic Acid A

Danshen ( Salvia miltiorrhiza Bunge) is one of the most used medicinal plants in the Oriental medicine and has been well studied for application in modern medicine. In our continuing study on chemical constituents of danshen cultivated in Vietnam, using chromatography separation resulted in the isolation of six phenolic compounds including a benzophenone, iriflophenone 2- O- α-L-rhamnopyranoside (1), and five phenolic acids including rosmarinic acid (2), rosmarinic acid methyl ester (3), rosmarinic acid ethyl ester (4), salvianolic acid A methyl ester (5) and salvianolic acid A ethyl ester (6) from the butanol portion of the danshen crude extract. Beside the typically main phenolic acid components, to our knowledge, iriflophenone 2- O- α-L-rhamnopyranoside (1) was first isolated from salvia sp. On biological testing, compound 1 showed strong antiproliferative activity on HL-60 leukemia cells with the IC50 of 8.9 μM; compounds 1 and 3–6 inhibited markedly nitric oxide production in lipopolysaccharide-treated RAW 264.7 cells.

scholarly journals Synthesis of DHA/EPA Ethyl Esters via Lipase-Catalyzed Acidolysis Using Novozym® 435: A Kinetic Study

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 565 ◽  
Author(s):  
Chia-Hung Kuo ◽  
Chun-Yung Huang ◽  
Chien-Liang Lee ◽  
Wen-Cheng Kuo ◽  
Shu-Ling Hsieh ◽  
...  
Keyword(s):  
Ethyl Ester ◽  
Ethyl Esters ◽  
Raw Material ◽  
Maximum Reaction Rate ◽  
Mechanism Model ◽  
Maximum Reaction ◽  
Substrate Ratio ◽  
Free Fatty Acid Form ◽  
The Relationship ◽  
Predictive Relationship

DHA/EPA ethyl ester is mainly used in the treatment of arteriosclerosis and hyperlipidemia. In this study, DHA+EPA ethyl ester was synthesized via lipase-catalyzed acidolysis of ethyl acetate (EA) with DHA+EPA concentrate in n-hexane using Novozym® 435. The DHA+EPA concentrate (in free fatty acid form), contained 54.4% DHA and 16.8% EPA, was used as raw material. A central composite design combined with response surface methodology (RSM) was used to evaluate the relationship between substrate concentrations and initial rate of DHA+EPA ethyl ester production. The results indicated that the reaction followed the ordered mechanism and as such, the ordered mechanism model was used to estimate the maximum reaction rate (Vmax) and kinetic constants. The ordered mechanism model was also combined with the batch reaction equation to simulate and predict the conversion of DHA+EPA ethyl ester in lipase-catalyzed acidolysis. The integral equation showed a good predictive relationship between the simulated and experimental results. 88–94% conversion yields were obtained from 100–400 mM DHA+EPA concentrate at a constant enzyme activity of 200 U, substrate ratio of 1:1 (DHA+EPA: EA), and reaction time of 300 min.

scholarly journals IN SILICO STUDIES OF THE SECONDARY METABOLITES OF SOLANUM TORVUM SW. FOR THEIR ANTIASTHMATIC ACTIVITY

2017 ◽  
Vol 9 (4) ◽  
pp. 38
Author(s):  
Soorya R. ◽  
Dhamodaran P. ◽  
Rajesh Kumar R. ◽  
Duraisamy B.
Keyword(s):  
Methyl Ester ◽  
Secondary Metabolites ◽  
Ethyl Ester ◽  
In Silico ◽  
Methanolic Extract ◽  
Acid Ethyl Ester ◽  
Docking Studies ◽  
Receptor Protein ◽  
Solanum Torvum ◽  
In Silico Studies

Objective: Solanum torvum Sw., Family: Solanaceae, commonly known as Turkey Berry is used by the traditional tribes for the treatment of cold, cough, tuberculosis, hepatotoxicity, cancer, etc. The action of the plant towards the treatment of these diseases has been proven except for asthma. The present study is to prove the antiasthmatic activity of methanolic extract and the secondary metabolites of Solanum torvum Sw using in silico docking studies in compare to reference standard Dexamethasone, a synthetic cortisone derivative.Methods: The GC-MS analysis of the dried methanolic extract of the dried fruits of Solanum torvum Sw. and the total saponin fraction has been carried out to know the important moieties that are responsible for the antiasthmatic activity.Results: The results from the docking studies showed that the compounds Cholesta-5,7,9-(11)-trien-3-ol,4,4-dimethyl, (3á); Lanosta-7,9-(11),20-triene-3α, 18-diol, diacetate and Cholestan-26-oic acid,3,7,12,24-tetrakis (acetyloxy), methyl ester, (3à,5á,7à,12à) were found to have significant scores of-6.8,-6.9 and-6.9 respectively towards Glucocorticoid receptor protein (Gr), (PDB id: 4UDC) which is very similar to the affinity of the standard (-7.1). These compounds passed the drug-likeness test. A modification in the structure can be brought, which makes the compounds more potent. The compounds 9, 12-Octadecadienoic acid, ethyl ester; Hexadecanoic acid, ethyl ester; 9-Octadecenoic acid (Z), methyl ester; Oxacycloheptadec-8-en-2-one, (8Z) have passed the Blood Brain Barrier (BBB) filter of the drug-likeness test.Conclusion: The antiasthmatic activity of the drug may be due to the similarity with the structure of Dexamethasone. Further research can be carried out in order to improve the clinical significance of these extracts and its metabolites.

scholarly journals Guest-Host Inclusion Complex Formation of 2-, 3-, and 4-Aminobenzoic Acids with Native and Modified Cyclodextrins

2016 ◽  
Vol 69 ◽  
pp. 10-21 ◽  
Author(s):  
Narayanasamy Rajendiran ◽  
J. Thulasidhasan ◽  
M. Jude Jenita
Keyword(s):  
Inclusion Complex ◽  
Inclusion Complexation ◽  
Aminobenzoic Acid ◽  
Time Resolved ◽  
H Nmr ◽  
Buffer Solutions ◽  
Aminobenzoic Acids ◽  
Modified Cyclodextrins ◽  
Ft Ir ◽  
Uv Visible

The inclusion complexation of 2-aminobenzoic acid (2ABA), 3-aminobenzoic acid (3ABA), and 4-aminobenzoic acid (4ABA) with α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), hydroxypropyl-α-cyclodextrin (HP-α-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) were studied in buffer solutions of differentpHs (pH~1 andpH~7) and it was carried out using UV-Visible, steady-state and time-resolved fluorescence. Dual fluorescence was observed for all the compounds in aqueous and CD medium. All the ABAs forms 1:1 inclusion complex at pH ~ 1 solution and mixture of 1:1 and 1:2 inclusion complex at pH ~7. With CDs, dual luminescence appeared at pH ~ 1 indicates, both NH3+and COOH groups are present in the interior of the CDs cavities. FT-IR,1H NMR, results suggest ABAs formed a stable inclusion complex with the CDs.

Preparation of eicosapentaenoic acid ethyl ester from fish oil ethyl esters by continuous batch chromatography

2019 ◽  
Vol 42 (24) ◽  
pp. 3697-3702
Author(s):  
Yanmei Li ◽  
Lei Zhao ◽  
Xiaolei Huang ◽  
Liguang Zhang ◽  
Jingjing Li ◽  
...  
Keyword(s):  
Eicosapentaenoic Acid ◽  
Fish Oil ◽  
Ethyl Ester ◽  
Acid Ethyl Ester ◽  
Ethyl Esters ◽  
Eicosapentaenoic Acid Ethyl Ester
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