Monoesters Of Dicarboxylic Acids Research Articles

Chromatographic and chromatospectral characteristic of dicarboxylic acid monoesters

Monoalkyl esters of benzene-1,2-dicarboxylic (phthalic) acid have not been reliably characterized by analytical parameters for their chromatographic and chromatospectral identification. Mass spectra of a series of monoalkyl phthalates (R = C1–C8) are discussed; their gas chromatographic retention indices on the RTX-5 polydimethylsiloxane stationary phase (5% phenyl groups) are determined. A linear dependence of indices on the number of carbon atoms in n-alkyl fragments of molecules and a correlation between the indices of any monoalkyl phthalates and corresponding diesters were used for the control of the data obtained. Using the last correlation, we found that most part of index values of mono (2-ethylhexyl) phthalate given in literature is wrong and, therefore, the results of identification of this compound in various samples must be revised. It was found that simplest monoalkyl phthalates are unstable during gas chromatographic separation, which may result in distortions of their mass spectra. To compare with monoalkyl phthalates, a similar series of monoesters of (Z)-butenedioic (maleic) acid was characterized. Retention indices of monoalkyl phthalates in reversed phase HPLC were determined and discussed.

ChemInform Abstract: Enzyme‐Mediated Enantioselective Hydrolysis of Dicarboxylic Acid Monoesters.

AbstractThe separation of the reaction products is accomplished by a simple extraction procedure.

Enzyme-Mediated Enantioselective Hydrolysis of Dicarboxylic Acid Monoesters

Enzyme-Mediated Enantioselective Hydrolysis of Dicarboxylic Acid Monoesters

ChemInform Abstract: A New Synthetic Entry to 3-Carboxamido-4-carboxylic Acid Derivatives of Isoxazole and Pyrazole.

Ethyl 2-amino-3-methoxycarbonyl-4-oxo-2-pentenoate (3) reacts with hydroxylamine or hydrazines to give isoxazole and pyrazole ortho-dicarboxylic acid esters 4 and 5, respectively. Partial hydrolysis of diesters 4 and 5 afforded the corresponding dicarboxylic acid monoesters 6 and 7. Amidation of the intermediate acid chlorides 8,9 followed by hydrolysis of 4-methylesters 10, 11 gave the title compounds 1 and 2, respectively.

Novel N-Hydroxymethylation of Phthalimide by Titanium Dioxide Photocatalyst in Methanol

photocatalyst are of great interest, because of the diversity in its role. Several attempts have been made to get some useful organic molecules in organic solvent, instead of aqueous phase. It was found that anhydrides were cleaved to give the monoesters of dicar-boxylic acids in good yields, when they were irradiated on TiO

Solvent-Free Asymmetric Anhydride Opening in a Ball Mill

The mechanochemical technique of ball milling has been applied to the asymmetric opening of meso-anhydrides, mediated by the cinchona alkaloid quinidine. A simple workup procedure affords the products, optically active dicarboxylic acid monoesters, in high yields, with up to 64% ee. With most substrates no column chromatography was needed. A range of various alcohols, as well as anhydrides, reacted well thus demonstrating the scope of this methodology. Even mixtures of purely solid components react, and no solvent is required (except during the workup). The possible use of almost equimolar amounts of starting materials significantly simplifies the product isolation compared to the standard solution reaction.

Synthesis of Bi‐ and Tricyclic Monoesters of Dicarboxylic Acids.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Kinetic and chemical resolution of different 1-phenyl-2-propanol derivatives

Seven chiral target molecules containing a hydroxy group have been resolved by both biocatalytic and chemical means. The lipase-catalyzed acylation mainly yielded the acylated derivative of the ( R)-alcohols with moderate enantiomeric excess and the enantiopure ( S)-alcohols. In the course of the chemical resolution, first the dicarboxylic acid monoesters of the target molecules were synthesized and the resolution of these monoesters was attempted by different homochiral bases. By re-resolution and/or optimization of the reaction time and/or recrystallization, respectively, each molecule was produced in very high enantiomeric purity.

Synthesis of bi-and tricyclic monoesters of dicarboxylic acids

A thermal addition of aliphatic dicarboxylic acids to bicyclo[2.2.1]-heptene hydrocarbons and to tricyclo[5.2.1.02,6]deca-3,8-diene was investigated and new samples of dicarboxylic acids alicyclic monoesters were synthesized. Some of monoesters synthesized have a pleasant fragrance and can find application as fragrance substances. They are also of interest as initial components for preparation of new organic compounds.

Role of entropy in increased rates of intramolecular reactions.

The rates of intramolecular condensation of a series of monoesters of dicarboxylic acids have been shown to be highly dependent on the nature of the intervening groups. To understand the origin of this effect, we estimated DeltaS(NAC,S), the entropy difference between the ensemble of accessible ground state conformers and a single ground state conformer having transition-state-like geometry. DeltaS(NAC,S) differs from the activation entropy for the reaction by DeltaS(TS,NAC), the difference in vibrational entropy between the selected ground state conformer and the transition state. The estimated values of DeltaS(NAC,S) correlate well (R(2) = 0.96 and 0.73 using dielectric constant values of 80 and 1, respectively) with experimentally determined reaction rate constants. Normal-mode analysis performed on minimized ground state conformations of each molecule suggests that the change in vibrational entropy makes only a small contribution to the total activation entropy. These results indicate that the conformational entropy difference between the transition and the ground states contributes significantly to the free energy of activation.

A new synthetic entry to 3‐carboxamido‐4‐carboxylic acid derivatives of isoxazole and pyrazole

AbstractEthyl 2‐amino‐3‐methoxycarbonyl‐4‐oxo‐2‐pentenoate (3) reacts with hydroxylamine or hydrazines to give isoxazole and pyrazole ortho‐dicarboxylic acid esters 4 and 5, respectively. Partial hydrolysis of diesters 4 and 5 afforded the corresponding dicarboxylic acid monoesters 6 and 7. Amidation of the intermediate acid chlorides 8,9 followed by hydrolysis of 4‐methylesters 10, 11 gave the title compounds 1 and 2, respectively.

A facile synthesis of pyrazole, isoxazole and pyrimidine ortho-dicarboxylic acid derivatives via β-enaminoketoesters

β-Alkoxycarbonyl-β-enaminoketoesters 1a,b react with hydrazines to give pyrazole ortho-dicarboxylic acid derivatives 3, 4 and 5. Similarly 1a reacts with hydroxylamine to give isoxazole 6 and with amidines and guanidine to give pyrimidine ortho-dicarboxylic acid monoesters 7a-c. The total or partial hydrolysis of selected heterocycles afforded the dicarboxylic acids 8, 9 and 10 and the dicarboxylic acid monoesters 11 and 12.

Enantioselective hydrolysis of racemic esters using pig liver esterase

The utilization of enzymes is a recent achievement in organic synthesis. There are many good reasons for the organic chemist to consider this approach. Enzymatic reactions are very fast and specific. The same transformations carried out by classical means in several days or weeks, can be achieved in hours or days using enzymes as catalysts. Enzymes act in mild conditions with high yields, and do not require sophisticated equipment. As compared with conventional catalysts, enzymes have an excellent reaction, substrate and stereo chemical specifity. Many enzymes are now commercially available and their prices are not prohibitive. Moreover, the enzymes can be immobilized through simple techniques on inert supports. The immobilized enzymes can be easily recovered from the reaction medium and reused many times. Enantioselective synthesis is an important area in which enzymes found large applications. Hydrolases, as lipase and pig liver esterase (PLE), have been successfully used to obtain optically pure alcohols, acids and esters. In this paper we report a new method for the immobilization of PLE on modified inorganic substrates and some applications of the immobilized PLE in synthesis of enantiomeric mono esters of dicarboxylic acids. As inorganic support we used silica with particle size of 40–80 mesh and average pore diameter of 550 Å. The surface isoelectric point of this material is relatively low. The support was derivatized with p-phenylenediamine and functionalized by diazotization to reaction with protein. The enzyme was covalently bonded to the support by reaction between diazonium salt and phenolic group of tyrosine residues. The immobilization yield was higher than 50% and the preparation was stored for one year at 4°C without significant loss of activity. Kinetic studies on immobilized PLE emphasized that Michaelis constant K M was very close to that of free enzyme, that means that no conformational changes in active site occurred during immobilization. Dimethyl 2-methyl-2-phenylmalonate was hydrolysed using immobilized PLE with slightly higher enatiomeric excess than reported earlier. The immobilized PLE can be removed from the reaction mixture by simple filtration and reused to hydrolyse other quantities of substrate without significant loss of enantioselectivity and with moderate reduction in chemical yield. Attempts to hydrolyse diethyl (3,5-di- tert-butyl-4-hydroxybenzyl)-malonate and ethyl (3,5-di- tert-butyl-4-hydroxybenzyl)cyanoacetate lead to complex mixtures of products that must be further investigated.

Ground State Conformations and Entropic and Enthalpic Factors in the Efficiency of Intramolecular and Enzymatic Reactions. 1. Cyclic Anhydride Formation by Substituted Glutarates, Succinate, and 3,6-Endoxo-Δ4-tetrahydrophthalate Monophenyl Esters

Intramolecular and enzymatic reactions require conformations in which the orbitals of reactants are properly aligned and van der Waals surfaces are in a near-attack conformation (NAC). Much of the changes in steric and electrostatic energies that take place in moving from the favored ground state conformation (FGSC) to the transition state are accounted for when the NAC has been assumed. Upon assessing the steric, electrostatic, and zero point energies, one is in position to calculate the probability of NAC formation. Using a series of monoesters of dicarboxylic acids, we have (i) created, via stochastic search, 10 000−40 000 minimized conformations per ester; (ii) chosen only the unique local minima conformations for each ester; (iii) determined the energies of each minimum conformation using MM3(92); (iv) identified the geometry of the NACs where the van der Waals overlap has not begun for the approach of carboxyl anion and ester carbonyl; and (v) calculated the mole fraction (probability, P) of each es...

Changes in mineral content of young maize plants under the influence of some dicarboxylic acid monoesters

Abstract Young maize (Zea mays L.) plants, grown hydroponically in a greenhouse, were leaf sprayed with MEIA (s‐monomethyl ester of itaconic acid), MESA (monoethyl ester of succinic acid), and MEAdA (monoethyl ester of adipic acid) at concentration 1250 ppm when the 4th leaf was fully‐developed. The influence of these EDA (esters of dicarboxylic acid) on root/shoot ratio (RSR) and nitrogen (N), phosphorus (P), and potassium (K) concentration, accumulation and efficiency was investigated. MEIA did not change the RSR, but MESA and MEAdA decreased it. EDA in most cases increased N, P, and K concentration and accumulation in the leaves and total amount of these elements in the plants. On the contrary, MESA and MEAdA decreased or did not change content of the investigated nutrient elements in the roots. Nitrogen physiological efficiency was affected by EDA treatment.

Effect of certain dicarboxylic acid monoesters on growth, chlorophyll content, chlorophyllase and peroxidase activities, and gas-exchange of young maize plants

The effect of some dicarboxylic acid monoesters on growth, chlorophyll content, chlorophyllase (EC 3.1.1.14), and total peroxidase (EC 1.11.1.7.) activities was examined in detached and intact leaves of maize (Zea mays) plants grown in a greenhouse. The β-monomethyl ester of itaconic acid (MEIA) at 1250 ppm had no effect on growth. However, application of the monoethyl ester of succinic (MESA) and monoethyl ester of adipic (MEAdA) acids (1250 ppm) resulted in an increased leaf area, fresh and dry weight of leaves and stems. These compounds retarded chlorophyll degradation in both detached and intact leaves. Chlorophyllase activity of the control and treated leaves was measured and related to chlorophyll content. Delaying of senescence by treatment with monoesters resulted in greater chlorophyll and protein content, compared with the control. However, the chlorophyllase activity/chlorophylla ratio in the treated plants decreased. Total peroxidase activity was higher in senescent leaves, but all treatments inhibited the increase of this enzyme activity. Prolonged carbon assimilative activity and enhanced leaf water use efficiency in treated plants was noted.

ChemInform Abstract: Synthesis of 1,3‐Dioxin‐4‐ones and Their Use in Synthesis. Part 16. 4‐Oxo‐1,3‐dioxin‐5‐carboxylic Acids and Related Compounds: Versatile Synthetic Intermediates for the Synthesis of 6‐Unsubstituted Six‐Membered Heterocyclic Compounds.

AbstractThe 4‐oxo‐1,3‐dioxins (V) are prepared by cleavage of hydroxymethylene Meldrum's acid (I) with the alcohols (II) and subsequent cyclization of the dicarboxylic acid monoesters (III) with the ketones (IV).

Preparation of Trifluoromethylated Compounds by Anodic Oxidation of 3-Hydroxy-2-trifluoromethylpropionic Acid

Abstract Electrochemical Oxidation of 3-hydroxy-2-trifluoromethylpropionic acid(1) produced 2,3-bis (trifluoromethyl)-1,4-butanediol in quantitative yield. Furthermore, 2-trifluoromethylated alcohols were obtained by the crossed Kolbe reaction of 1 with carboxylic acids or dicarboxylic acid mono esters.

ChemInform Abstract: Irreversible Blockage of Opioid Receptor Types by Ester Homologues of β‐Funaltrexamine.

AbstractThe acid chlorides (IV), obtained from maleic anhydride (I) via the dicarboxylic acid monoesters (III), are coupled with 6β‐naltrexamine (V) to give the ester homologues (VIa) ‐ (VIe) of β‐funaltrexamine (VIf).

Effects of monoesters of dicarboxylic acids on jet fuel lubricity

The authors have prepared monoesters of dicarboxylic acids (DCAs) and aliphatic alcohols to study their effects on jet fuel lubricity. The effects of the synthesized compounds on the lubricity of a hydrotreated jet fuel were evaluated in a KIIGA-2 unit. The monoesters were added to the fuel at a concentration of 0.15 mole/m/sup 3/ and an analysis of the data shows that the monoesters of the DCAs do have significant effects on the fuel lubricity. The lubricity effect of these compounds depends on the molecular structure. It was found that dicarboxylic acids and higher fatty alcohols can be used to prepare effective lubricity additives for hydrotreated jet fuels.