4-chlorobutyric Acid Research Articles

Trinity Strategy: Enabling Perovskite as Hydrophilic and Efficient Fluorescent Nanozyme for Constructing Biomarker Reporting Platform.

Water instability and sensing homogeneity are the Achilles' heel of CsPbX3 NPs in biological fluids application. This work reports the preparation of Mn2+:CsPbCl3@SiO2 yolk-shell nanoparticles (YSNPs) in aqueous solutions created through the integration of ligand, surface, and crystal engineering strategies. The SN2 reaction between 4-chlorobutyric acid (CBA) and oleylamine (OAm) yields a zwitterionic ligand that facilitates the dispersion of YSNPs in water, while the robust SiO2 shell enhances their overall stability. Besides, Mn2+ doping in YSNPs not only introduces a second emission center but also enables potential postsynthetic designability, leading to the switching from YSNPs to MnO2@YSNPs with excellent oxidase (OXD)-like activity. Theoretical calculations reveal that electron transfer from CsPbCl3 to in situ MnO2 and the adsorption-desorption process of 3,3',5,5'-tetramethylbenzidine (TMB) synergistically amplify the OXD-like activity. In the presence of ascorbic acid (AA), Mn4+ in MnO2@YSNPs (fluorescent nanozyme) is reduced to Mn2+ and dissociated, thereby inhibiting the OXD-like activity and triggering fluorescence "turn-on/off", i.e., dual-mode recognition. Finally, a biomarker reporting platform based on MnO2@YSNPs fluorescent nanozyme is constructed with AA as the reporter molecule, and the accurate detection of human serum alkaline phosphatase (ALP) is realized, demonstrating the vast potential of perovskites in biosensing.

Effect of carbon chain length of chlorinated carboxylic acids on morphology of the carbon films electrodeposited from aqueous solutions

Diamond-like carbon films can be electrodeposited from organic acids in aqueous solutions. Chlorinated carboxylic acids with different chain lengths, ie. chloroacetic acid, 3-chloropropionic acid, 4-chlorobutyric acid and 5-chlorovaleric acid, were used as the carbon sources in the electrolytes. It showed an interesting even-odd effect of carbon chain length on the surface morphology of the electrodeposited carbon films. The odd carbon-numbered chlorinated carboxylic acids lead to smooth carbon films whose morphologies were insensitive to the deposition parameters. On the contrary, the morphologies of the films obtained from the even carbon-numbered chlorinated carboxylic acids were island-like and dependent on the film thickness. Fourier transform infrared and Raman analysis indicated that the electrodeposited diamond-like carbon films were hydrogenated and contaminated by oxygen.

Cooperative Hydrogen Bonds of Macromolecules. 3. A Model Study of the Proximity Effect

Experimental and theoretical evidence for the proximity effect as a basic mechanism of the hydrogen bond cooperativity was obtained in a model system. Hydrogen bond (HB) interaction between poly(4-vinylpyridine) (PVP) and selected acids as HB donors was studied using PFG NMR self-diffusion measurements, 1H NMR longitudinal relaxation and quantum-mechanical DFT calculations. Bivalent HB donors, such as glutaric (GA) and adipic acid (AA), were compared to univalent donors 4-chlorobutyric acid, 4-acetylbutyric acid and 5-chlorovaleric acid. PFG NMR established substantially larger HB equilibrium constants for AA and, in particular, GA than for univalent donors, thus indicating cooperativity of COOH groups in bivalent donors. According to the values of these constants, the fraction of the transiently bound GA and AA molecules, which are bound by two hydrogen bonds, is 0.70 and 0.63, respectively. This result, which means substantial cooperativity in particular in GA, was then independently verified by a relaxation study comparing longitudinal relaxation rates of univalent and bivalent donors. Analysis of relaxation led to the same probabilities that HB of one COOH group of a bivalent donor will be accompanied by HB of another COOH group of the same molecule, namely 0.70 for GA and 0.63 for AA. Such cooperativity must be due to the proximity effect, i.e., the lowering of the entropy demand of the next binding by the motional restriction imposed by the already existing bonds. This conclusion is in excellent agreement with DFT calculations on the interaction of GA with a model vinylpyridine dimer, which predict preference of double binding of the same GA molecule over that of two GA molecules and show that this preference is due to a substantially lower entropy demand.

Synthesis and Magnetic Relaxation of [Mn12O12(O2CCH2CH2CH2Cl)16(H2O)4] Complex

<TEX>$Mn_{12}O_{12}(O_2CCH_2CH_2CH_2Cl)_{16}(H_2O)_4]$</TEX> (noted as <TEX>$Mn_{12}$</TEX>-BuCl), a new polynuclear complex of manganese chlorobutyrate has been successfully prepared by substitution of acetate with 4-chlorobutyric acid. The <TEX>$Mn_{12}-BuCl$</TEX> crystallizes into triclinic space group P-1 with a = 14.5560(11) <TEX>${\AA}$</TEX>, b = 14.5819(11) TEX>${\AA}$</TEX>, c = 27.265(2) <TEX>${\AA}$</TEX>, <TEX>${\alpha}\;=\;84.1140(10)^{\circ}\;,\;{\beta}\;=\;88.805(2)^{\circ},\;{\gamma}\;=\;89.8820(10)^{\circ}$</TEX>, and Z = 2. The local environments of manganese 3+ and 4+ ions of the title compound are close to those of other <TEX>$Mn_{12}$</TEX> compounds. The electrochemical data for <TEX>$Mn_{12}-BuCl$</TEX> involve reversible reactions of two-electron reductions. The <TEX>$Mn_{12}-BuCl$</TEX> also presents magnetic relaxation below 10 K implying that each molecule behaves as a single molecule magnet.

Determination of chloral hydrate metabolites in human plasma by gas chromatography-mass spectrometry

Chloral hydrate (CH) is a widely used sedative. Its pharmacological and toxicological effects are directly related to its metabolism. Prior investigations of CH metabolism have been limited by the lack of analytical techniques sufficiently sensitive to identify and quantify metabolites of CH in biological fluids. In this study a gas chromatography/mass spectrometry (GC/MS) method was developed and validated for determining CH and its metabolites, monochloroacetate (MCA), dichloroacetate (DCA), trichloroacetate (TCA) and total trichloroethanol (free and glucuronidated form, TCE and TCE-Glu) in human plasma. Of these, DCA and MCA are newly identified metabolites in humans. The drug, its plasma metabolites and an internal standard, 4-chlorobutyric acid (CBA), were derivatized to their methyl esters by reacting with 12% boron trifluoride-methanol complex (12% BF 3-MeOH). The reaction mixture was extracted with methylene chloride and analyzed by GC/MS, using a selected ion monitoring (SIM) mode. The quantitation limits of MCA, DCA, TCA, and TCE were between 0.12 and 7.83 μM. The coefficients of variation were between 0.58 and 14.58% and the bias values ranged between −10.03 and 14.37%. The coefficients of linear regression were between 0.9970 and 0.9996.

P3D122 - SV40 virus-specific DNA sequences and etiology of malignant mesothelioma in Finland

Chloral hydrate (CH) is a widely used sedative. Its pharmacological and toxicological effects are directly related to its metabolism. Prior investigations of CH metabolism have been limited by the lack of analytical techniques sufficiently sensitive to identify and quantify metabolites of CH in biological fluids. In this study a gas chromatography/mass spectrometry (GC/MS) method was developed and validated for determining CH and its metabolites, monochloroacetate (MCA), dichloroacetate (DCA), trichloroacetate (TCA) and total trichloroethanol (free and glucuronidated form, TCE and TCE-Glu) in human plasma. Of these, DCA and MCA are newly identified metabolites in humans. The drug, its plasma metabolites and an internal standard, 4-chlorobutyric acid (CBA), were derivatized to their methyl esters by reacting with 12% boron trifluoride-methanol complex (12% BF3-MeOH). The reaction mixture was extracted with methylene chloride and analyzed by GC/MS, using a selected ion monitoring (SIM) mode. The quantitation limits of MCA, DCA, TCA, and TCE were between 0.12 and 7.83 μM. The coefficients of variation were between 0.58 and 14.58% and the bias values ranged between −10.03 and 14.37%. The coefficients of linear regression were between 0.9970 and 0.9996.

Method for Quantitation of Total Vitamin B12 in Foods Using a Highly Fluorescent Vitamin B12 Derivative

A highly fluorescent vitamin B12 derivative was readily prepared with a fluorescent reagent [6,7-dimethoxy-1-methyl-2(1H)-quinoxaline-3-propionylcarboxylic acid hydrazide] specific for carboxylic acids. Hydroxovitamin B12 was reduced by NaBH4, and then 4-chlorobutyric acid was added to form carboxypropyl vitamin B12, which was labeled with the fluorescent reagent in the presence of carbodiimide. An assay for vitamin B12 with the fluorescent vitamin B12 derivative and hog intrinsic factor was devised. Vitamin B12 could be assayed over a range of 0.2−10 μg/L by this method, which was useful for vitamin B12 assay in foods. Keywords: Vitamin B12; cobalamin; fluorescence assay; intrinsic factor

Production of biodegradable copolyesters of 3-hydroxybutyrate and 4-hydroxybutyrate by Alcaligenes eutrophus

New copolyesters of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB) were produced by Alcaligenes eutrophus from various carbon sources of 4-hydroxybutyric acid, 4-chlorobutyric acid, 1,4-butanediol, and γ-butyrolactone. The composition of copolyesters varied from 0 to 37 mol% 4HB, depending on the carbon sources supplied. The biosynthetic pathway of copolyesters has been discussed. The copolyester film was biodegradable in soil and activated sludge. The rate of biodegradation was enhanced by the presence of 4HB units.

The mechanisms of the homogeneus, unimolecular elimination kinetics of ethyl 4‐chlorobutyrate and 4‐chlorobutyric acid in the gas phase

AbstractEthyl 4‐chlorobutyrate, which is reexamined, pyrolyzes at 350–410°C to ethylene, butyrolactone, and HCl. Under the reaction conditions, the primary product 4‐chlorobutyric acid is responsible for the formation of γ‐butyrolactone and HCl. In seasoned vessels, and in the presence of a free‐radical inhibitor, the ester elimination is homogeneous, unimolecular, and follows a first‐order rate law. For initial pressures from 69–147 Torr, the rate is given by the following Arrhenius expression: log k1(s−1) = (12.21 ± 0.26) − (197.6 ± 3.3) kJ mol−1 (2.303RT)−1. The rates and product formation differ from the previous work on the chloroester pyrolysis.4‐Chlorobutyric acid, an intermediate product of the above substrate, was also pyrolyzed at 279–330°C with initial pressure within the range of 78–187 Torr. This reaction, which yields γ‐butyrolactone and HCl, is also homogeneous, unimolecular, and obeys a first‐order rate law. The rate coefficient, is given by the following Arrhenius equation: log k1(s−1) = (12.28 ± 0.41) − (172.0 ± 4.6) kJ mol−1 (2.303RT)−1. The pyrolysis of ethyl chlorobutyrate proceeds by the normal mechanism of ester elimination. However, the intermediate 4‐chlorobutyric acid was found to yield butyrolactone through anchimeric assistance of the COOH group and by an intimate ion pair‐type of mechanism. Additional evidence of cyclic product and neighboring group participation is described and presented.

Electrophilic alkylation of o-and m-carboranes by 4-chlorobutyric acid and 5-chlorovaleric acid in the presence of AlCl3

1. The alkylation of 1-isopropyl-o-carborane by 4-chlorobutyric acid under the action of AlCl3 produces 4-(1-isopropyl-o-carboran-9-yl)butyric acid. 2. o-Carborane, 1-isopropyl-o-carborane, and m-carborane are alkylated by 5-chlorovaleric acid under the action of AlCl3 with isomerization of the alkyl chain and the formation of the corresponding 4-(o-and m-carbon-9′-yl)valeric acids. 3. The alkylation of o-carborane by an excess of 5-chlorovaleric acid in the presence of AlCl3 results in the introduction of two acid residues into the nucleus with the formation of 9,12-bis(3′-carboxybutyl)-o-carborane. 4. The alkylation of o-carborane by 4-pentenoic acid under the action of AlCl3 with the formation of 4-(o-carboran-9′-yl)valeric acid has been carried out.

Neuropharmacological effects induced by butanol, 4-hydroxybutyrate, 4-mercaptobutyric acid thiolactone, tetrahydrofuran, pyrrolidine, 2-deoxy- d-glucose and related substances in the rat

The present study evaluated in the rat the gross behavioural and electroencephalographic activity produced by several short chain aliphatic alcohols, fatty acids, some of their derivatives and some heterocyclic 5-ring compounds that have structural similarities mainly to 4-hydroxybutyric acid and butyrolactone. 4-Hydroxybutyric acid (and butyrolactone) produced a progression of EEG and behavioural changes characteristic of generalized non-convulsive epilepsy. During the period of continuous EEG high amplitude slow wave activity, the rat was cataleptoid and during periods of spiking with electrical silence, the righting reflex was lost. Non-convulsive epileptoid activity with some characteristics similar to that produced by 4-hydroxybutyric acid and butyrolactone was observed following administration of butanol, 2-butanol, 1,4-butane-diol, 4-chlorobutanol, 4-methoxybutyric acid, 4-chlorobutyric acid, tetrahydrofuran and 2-deoxy- d-glucose. Convulsive seizures were observed following 4-mercaptobutyric acid thiolactone and pyrrolidine. The results are discussed with regard to the structural components necessary to elicit epileptoid activity and the possible mechanism of action. It is suggested that part of the mechanism of action of these substances may involve inhibition of the enzymes involved in brain glutamate and aspartate metabolism.

The Synthesis of 4-Chlorobutyric Acid Esters from γ-Butyrolactone

The Synthesis of 4-Chlorobutyric Acid Esters from γ-Butyrolactone