Carboxylic Acid Ethyl Ester Research Articles

Lipase-catalyzed chemospecific O-acylation of 3-mercapto-1-propanol and 4-mercapto-1-butanol

The lipase-catalyzed chemospecific O-acylation of 3-mercapto-1-propanol and 4-mercapto-1-butanol by several aliphatic carboxylic acid ethyl esters are described. Similar treatment on 1-mercapto-2-propanol and 3-mercapto-2-butanol did not yield the expected O-acyl derivatives.

Effect of the Growth Retardant 3,5-Dioxo-4-butyryl-cyclohexane Carboxylic Acid Ethyl Ester, an Acylcyclohexanedione Compound, on Fruit Growth and Gibberellin Content of Pollinated and Unpollinated Ovaries in Pea.

Treatment of pollinated pea (Pisum sativum L. cv Alaska, line V1) ovaries with 3,5-dioxo-4-butyryl-cyclohexane carboxylic acid ethyl ester (LAB), an acylcyclohexanedione derivative that competitively inhibits 2-oxoglutarate-dependent gibberellin (GA) dioxygenases, caused a reduction of pod elongation proportional to the amount of inhibitor applied. The effect of LAB was counteracted by GA1 and GA3, and partially by GA20. The inhibitor decreased the contents of GA1 and GA3 (the purported active GAs) and GA8, increased those of GA19 and GA20, and did not affect that of GA29 in both the pod and the developing seeds. These results provide evidence that GA1 and/or GA3 control pod development in pea and show that GA20 is not active per se. In contrast to its effect on pollinated ovaries, LAB promoted parthenocarpic development of unpollinated ovaries, which is associated with an increase of GA1 and GA8 content. The inhibitor enhanced the response of unpollinated ovaries to GA1 and GA20, but it did not alter the response to GA3. LAB is proposed to promote parthenocarpic development and enhance the response to exogenous GAs by blocking the 2[beta]-hydroxylation of GA1 more efficiently than 3[beta]-hydroxylation of GA20.

An improved procedure for chemospecific acylation of 2-mercaptoethanol by lipase-catalyzed transesterification

Various O-acyl derivatives of 2-mercaptoethanol have been obtained enzymatically by lipase-catalyzed chemospecific esterification reactions of the substrate and several aliphatic carboxylic acid ethyl esters.

N- and C-Glycosylation of 6,7-Difluoro-1,4-dihydro-4-oxo-3-quinoline Carboxylic Acid Ethyl Ester

1,2,3,4,6-Penta-O-acetyl-α-D-glucopyranose reacts with a silylated ethyl ester of 6,7-difluoro-1,4-dihydro-4-oxo-3-quinoline carboxylic acid 1 with C-glycosylation to subsequently afford the ethyl ester of 8-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)- 6,7-difluoro-1,4-dihydro-4-oxo-3-quinoline carboxylic acid 4; on the contrary, condensation of 1,2-di-O-acetyl-3,5-di-O-benzoyl- D-xylofuranose with the heterocycle 1 results in an N-glycosylation product 2.

Synthesis of 2-p-aminobenzyl-3-methyl- and 2-p-aminobenzyl-3-benzyl derivatives of diethylenetriaminepentaacetic acids (DTPA): carbon backbone modified bifunctional chelating agents.

A convenient preparation of new bifunctional chelating agents ( 1a) and ( 1b) were achieved based on a practical synthesis of 2-p-nitrobenzyl-3-methyl ( 9a) and 2-p-nitrobenzyl-3-benzyl ( 9b) diethylenetriamines starting from optically pure p-nitro-L-phenylalanine and triflates of 2-hydroxy carboxylic acid ethyl esters. These backbone substituted chelating agents could provide the stable complexation with radiometals.

Synthesis of enantiomerically enriched α-trifluoromethylated acids, esters and ketones

α-Trifluoromethylated carboxylic acids have been obtained with high optical purity by enzymatic hydrolysis. Further, the synthesis of optically active α-trifluoromethylated ketones by the thermolysis of diallyl alcohols, produced from the reaction of Grignard reagent and optically pure α-trifluoromethylated carboxylic acid ethyl esters, is described.

Effect of the growth retardant LAB 198 999, an acylcyclohexanedione compound, on epicotyl elongation and metabolism of gibberellins A1 and A20 in cowpea

The effect of LAB 198 999 [3,5-dioxo-4-butyryl-cyclohexane carboxylic acid ethyl ester; a new plant growth retardant which competitively inhibits 2-oxoglutarate-dependent gibberellin (GA) dioxygenases] on elongation and in-vivo [(3)H]GA1 and [(3)H]GA20 metabolism in cowpea (Vigna sinensis L. cv Blackeye pea No. 5) epicotyls has been investigated. Gibberellins and LAB 198 999 were injected into the epicotyl at 25-30 mm from the apex. In intact seedlings, epicotyl elongation was inhibited by LAB 198 999 (25 μg · epicotyl(-1)), and the inhibition was counteracted by GA1 but not by GA20. In contrast to intact seedlings, the inhibitor enhanced epicotyl elongation in de-bladed seedlings and expiants, in the latter case proportionally to the amount of inhibitor applied (up to 50 μg · epicotyl(-1)), but not in explants made from paclobutrazol-treated seedlings. The inhibitor also enhanced dramatically the elongation induced in paclobutrazol-treated expiants by GA1, but not by GA20. The promotive effect of LAB 198 999 was associated with increased contents of GA1 and GA8 in the growing region of the epicotyl, indicating a dependence on endogenous GAs. The effect of LAB 198999 decreased progressively with the age of the seedlings, probably as a consequence of a decreased level of GAs in the epicotyl. Gibberellin substrates and metabolites in the growing region of the epicotyl (upper 20 mm) were fractionated and identified tentatively by high-performance liquid chromatography and radiocounting using a homogeneous on-line radioactivity detector. The metabolism of [(3)H]GA1(t) (tentative) to [(3)H]GA8(t), and that of [(3)H]GA20(t) to [(3)H]GA1(t) and [(3)H]GA29(t) in the epicotyl were blocked by LAB 198 999, that of the former more efficiently than the latter. The results presented support the hypothesis that GA1 is the active GA controlling elongation of cowpea epicotyls. They also show that both the promotion of epicotyl elongation in explants and the enhancement of the effect of exogenous GA1 by LAB 198 999 are the result of the inhibitor blocking the in-vivo 2β-hydroxylation of GA1.

State mixing in indoline derivatives: A steady-state and dynamical-fluorescence spectroscopic study

The polarity-dependent Herzberg—Teller mixing of 1L a- and 1L b-type excited states is investigated for N-ethyl indolines bearing as p-acceptor substituent a cyano (EIN) and a carboxylic acid ethyl ester (EICEE) function. EICEE shows strongly temperature-dependent fluorescence spectral shapes. Low-temperature time-resolved measurements indicate a temporal evolution of the excited-state nature on a time scale faster than that of the solvent relaxation and of the dynamical solvatochromism.

Inhibition of gibberellin 2β-hydroxylases by acylcyclohexanedione derivatives

Two acyleyclohexanedione growth retardants, 3,5-dioxo-4-butyryl-cyclohexane carboxylic acid ethyl ester and 5-(3,5,-dioxo-4-propionylcyclohexane)-pentanoic acid, were shown to be effective inhibitors of partially purified gibberellin 2β-hydroxylases from imbibed Phaseolus vulgaris seeds. The former, which was the more potent inhibitor, acted competitively with respect to 2-oxoglutarate, a cofactor for the enzymes, when the inhibitor was present at low (< lO μM) concentrations. Both compounds were much more effective than 2,4-, 2,5- and 2,6-dicarboxypyridines, which are known to inhibit prolyl 4-hydroxylase, a mechanistically related enzyme. The free acid was more active than the ethyl ester; the acyl side chain was essential for activity. This free acid was shown by computer modelling to have close structural similarity to 2-oxoglutarate. At superoptimal concentrations of 2-oxoglutarate, low concentrations of the inhibitors stimulated enzyme activity, perhaps by preventing its inactivation by 2-oxoglutarate.

Behavioral effects induced by beta CCE in free or restrained rhesus monkeys (Macaca mulatta)

Behavioral effects of the IV injection of beta carboline acid carboxylic acid ethyl ester (beta CCE) were studied in chair-restrained rhesus monkeys and in rhesus monkeys freely moving in their cages. Observation made during the administration of increasing doses of beta CCE (0.5, 1 and 2 mg/kg) evidence behaviors reflecting a state of anxiety. The similarity of results obtained under the two experimental conditions excludes a potential effect of restraint on the behavioral expression of effect induced by the administered molecule. Convulsions observed in three subjects out of twelve should call for great caution when using this molecule.

4851426 Ethoxycarbonyloxy ethyl esters of non-steroidal anti-inflammatory carboxylic acids and pharmaceutical compositions thereof: Davi Ladkani, Haim Yellin, Ben Weiner, David Avnir, Jerusalem, Israel assigned to Teva Pharmaceutical Industries Ltd

4851426 Ethoxycarbonyloxy ethyl esters of non-steroidal anti-inflammatory carboxylic acids and pharmaceutical compositions thereof: Davi Ladkani, Haim Yellin, Ben Weiner, David Avnir, Jerusalem, Israel assigned to Teva Pharmaceutical Industries Ltd

Organometallic substrates of enzymes: Lipase catalysed transesterifications in organic solvents via O-stannyl ethers

Lipases from pig pacreas and from Chromobacterium viscosum (but not from Candida cylindracea) catalyze transesterification reactions between ethyl esters of carboxylic acids and tributylstannyl ethers of primary and secondary alcohols. At concentrations 1 M or higher in anhydrous hydrocarbons, use of these nucleophilic derivatives of alcohols gives reaction rates ca. three times higher than those for the corresponding alcohols.

Polarity, polarizability, and structure of esters. 2. Conformations of ethyl formate, ethyl acetate, isopropyl formate, and isopropyl acetate in solutions

1. The ethyl esters of carboxylic acids in solutions are characterized by the participation of considerable numbers of rotamers with a COCC dihedral angle equal to ip90° in the conformational equilibrium with respect to the O-Et bond. 2. The isopropyl esters in solutions are characterized by a conformation with a COCH dihedral angle equal to ∿40°.

Alkylation of haemoglobin, plasma proteins and DNA in the mouse by diethylnitrosamine

Covalent binding to haemoglobin, plasma proteins and DNA was determined after intraperitoneal administration of radiolabelled diethylnitrosamine to mice. The level of alkylation of DNA in liver--the main site of activation--was found to be about two orders of magnitude higher than the level of alkylation of haemoglobin, if compared per unit weight of macromolecule. A high reactivity towards nucleophilic oxygen atoms was characteristic of the reaction pattern. Carboxylic acid ethyl esters, ethylserine and ethylthreonine are important reaction products in the proteins.

Syntheses and sleeping-time-prolonging effect of nitramarine and related compounds.

Nitramarine (1), which possesses a β-carboline nucleus, was synthesized by two routes. First, we applied an intramolecular thermal cyclization of the 1-azahexatrienesystem in heteroaromatics such as 2. Although no intermediate (9 or 10) could be isolated, heating of 7 in toluene or of 8 in odichlorobenzene in the presence of hydroxylamine gave nitramarine (1) or its derivative (11), respectively. On the other hand, the Pictet?Spengler reaction between (±) -tryptophan ethyl ester (12) and 2-quinoline carbaldehyde (13) gave nitramarine carboxylic acid ethyl ester (11). Subsequent hydrolysis followed by decarboxylation gave 1. Nitramarine carboxylic acid (15) and carboxamide (16) were found to prolong the sleeping time of mice.

The effect of midazolam and ?-carboline carboxylic acid ethyl ester on behaviour, steroid hormones and central monoamine metabolites in social groups of talapoin monkeys

Established social groups of talapoin monkeys show rank-related differences in aggressive, social and sexual behaviours and visual monitoring, as well as in endocrine and monoamine profiles. Here we describe the effects on these variables of an "anxiogenic drug", beta-carboline carboxylic acid ethyl ester (beta-CCE), and an anxiolytic drug (midazolam) given to either dominant or subordinate male talapoins. In dominant animals beta-CCE increased aggression and visual monitoring but reduced sexual behaviour. Treatment of subordinate animals with beta-CCE served only to increase visual monitoring. Conversely, treatment with a non-sedative acute dose of midazolam in dominants reduced aggressive behaviour and increased sexual behaviour, whereas in subordinates no behavioural changes were noted. Significant effects on endocrine and neurochemical variables were not seen with the acute drug treatments employed. Nevertheless, the results show that drugs which modulate anxiety produce status-dependent behavioural effects.

ChemInform Abstract: A Facile "One‐Pot" Synthesis of 2,9‐Disubstituted 8‐Azapurin‐6‐ones (3,5‐Disubstituted 7‐Hydroxy‐3H‐1,2,3‐triazolo[4,5‐d]pyrimidines).

AbstractCyanacetamid (I) und Benzylazid (II) reagieren in Gegenwart von Ethylat zu den Triazol‐Zwischenstufen (III), die mit den Estern (IV) zu den 8‐Aza‐purin‐6‐onen (V) cyclisiert werden können.

The effects of β-carboline carboxylic acid ethyl ester and its free acid, administered ICV, on the anticonvulsant activity of diazepam and sodium valproate in the mouse

The effects of intracerebroventricular (ICV) β-carboline carboxylic acid ethyl ester (β-CCE) and its free acid on the protective effects of diazepam against leptazol- and R05-3663-induced convulsions were investigated in mice and compared with their effects on the antileptazol effect of sodium valproate, in an attempt to demonstrate a specific central effect of β-CCE on benzodiazepine function. The results show that a small dose (1 μg) of β-CCE but not its free acid (in doses up to 100 μg) was able to reverse the protective effects of diazepam against leptazol- and R05-3663-induced convulsions, whereas the effects of sodium valproate, a non-benzodiazepine anticonvulsant, could not be reversed by these β-carboline derivatives.

A facile “one pot” synthesis of 2,9‐disubstituted 8‐azapurin‐6‐ones (3,5‐disubstituted 7‐hydroxy‐3H‐1,2,3‐triazolo[4,5‐d]pyrimidines)

AbstractA series of title compounds have been synthesized by utilising benzylazide, cyanoacetamide, ethyl or methyl esters of aliphatic or aromatic carboxylic acids and sodium ethoxide as catalyst.

Microbial Transformation of Esters of Chlorinated Carboxylic Acids

Two groups of compounds were selected for microbial transformation studies. In the first group were carboxylic acid esters having a fixed aromatic moiety and an increasing length of the alkyl component. Ethyl esters of chlorine-substituted carboxylic acids were in the second group. Microorganisms from environmental waters and a pure culture of Pseudomonas putida U were used. The bacterial populations were monitored by plate counts, and disappearance of the parent compound was followed by gas-liquid chromatography as a function of time. The products of microbial hydrolysis were the respective carboxylic acids. Octanol-water partition coefficients (K(ow)) for the compounds were measured. These values spanned three orders of magnitude, whereas microbial transformation rate constants (k(b)) varied only 50-fold. The microbial rate constants of the carboxylic acid esters with a fixed aromatic moiety increased with an increasing length of alkyl substituents. The regression coefficient for the linear relationships between log k(b) and log K(ow) was high for group 1 compounds, indicating that these parameters correlated well. The regression coefficient for the linear relationships for group 2 compounds, however, was low, indicating that these parameters correlated poorly.