Oxalic Acid Bis Research Articles

Fabrication of an Er3+ PVC membrane sensor based on oxalic acid bis[2-[(phenylamino)carbonyl]hydrazide

AbstractA highly selective and sensitive Er 3+ sensor was constructed with a polyvinyl chloride matrix membrane containing oxalic acid bis[2-[(phenylamino)carbonyl]hydrazide] as a neutral carrier, sodium tetraphenyl borate as a cationic additive and nitrobenzene as a plasticizing solvent mediator. The proposed sensor exhibits linear potential response with a Nernstian slope of 19.7 ± 0.4 mV decade −1 of activity in the Er 3+ concentration range of 1.0 × 10 −6 to 1.0 × 10 −2 mol dm −3 in the pH range of 2.7-10.2. It has a very short response time (<10 s), a detection limit of 5.8 × 10 −7 mol dm −3 and good selectivity relative to a wide variety of other metal ions including common alkali, alkaline earth, heavy and transition metal ions. The sensor can be used for at least 2 months without any considerable divergence in potentials. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of 1.0 × 10 −4 mol dm −3 of Er 3+ ions with a 1.0 × 10 −2 mol dm −3 EDTA. It was also used in the indirect determination of F − ions in some mouthwash solutions.Graphical abstract[IMAGE]

A multi-technique approach to predicting the molecular structure of cuprizone in the gas phase and in the crystalline state

Cuprizone (oxalic acid bis(cyclohexylidene hydrazide)) is a potent neurotoxin that is known to induce the destruction of the myelinic sheath which covers the cells of the central nervous system (CNS). The mechanism of action has not yet been elucidated due to lack of structural information. We have performed an ab initio prediction of the molecular structure by high-level quantum chemical methods, leading to two possible conformers of a nearly identical energy: A, for which an analysis of the electron density distribution shows more propensity for intermolecular bonding, and B, with stronger intramolecular liaison. Having obtained suitable single crystals, we report a detailed study of the crystal and molecular structure, which reveals that the molecular and crystal centers of symmetry coincide, and that the actual conformer is A, as expected, and in agreement with the ab initio prediction. Further information is gained by optimization of the crystal structure by Car-Parrinello molecular dynamics, yielding good agreement with observation. Infrared and Raman spectra show mutual exclusion, suggesting a centrosymmetric molecule with carbonylic bonds in trans configuration; moreover, vibrational frequencies calculated ab initio also show excellent agreement with observations. We thus present a multi-technique approach to the prediction and interpretation of various aspects of the complex interplay between intra- and intermolecular forces.

Synthesis of Unsymmetrical Bis(imidoyl)dichlorides of Oxalic Acid.

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.

Synthesis of Unsymmetrical Bis(imidoyl)dichlorides of Oxalic Acid

Unsymmetrical oxalic acid-bis(imidoyl)dichlorides were prepared from ethyl 2-chloro-2-oxoacetate in three steps.

Chromium(III) Ion Selective Electrode Based on Oxalic Acid Bis(Cyclohexylidene Hydrazide)

AbstractA poly(vinyl chloride) membrane sensor based on oxalic acid bis (cyclohexylidene hydrazide) as membrane carrier was prepared and investigated as a Cr(III)‐selective electrode. The electrode reveals a Nernstian behavior (slope 19.8±0.4 mV decade−1) over a wide Cr(III) ion concentration range 1.0×10−7–1.0×10−2 mol dm−3 with a very low limit of detection (i.e., down to 6.3×10−8 mol dm−3). The potentiometric response of the sensor is independent of the pH of the test solution in the pH range 1.7–6.5. The electrode possesses advantage of very fast response, relatively long lifetime and especially good selectivity to wide variety of other cations. The sensor was used as an indicator electrode, in the potentiometric titration of chromium ion and in the determination of Cr(III) in waste water and alloy samples.

Synthesis of Unsymmetrical Pyrrolo[3,2‐b]pyrrole‐2,5‐diones.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Efficient synthesis of 2-alkylidene-3-iminoindoles, indolo[1,2-b]isoquinolin-5-ones, delta-carbolines, and indirubines by domino and sequential reactions of functionalized nitriles.

The sodium hydride mediated cyclization of arylacetonitriles with oxalic acid bis(imidoyl) dichlorides, aza-analogues of oxalyl chloride, afforded functionalized 2-alkylidene-3-iminoindoles with very good regio- and E/Z selectivity. Excellent chemoselectivities were observed for functionalized substrates. Based on these results a domino "cyclization-lactamization" reaction of bis(imidoyl) chlorides with methyl 2-(cyanomethyl)benzoate was developed. This process allowed a convenient one-pot synthesis of indolo[1,2-b]isoquinolin-5-ones related to tryptanthrin. A new and convenient synthesis of delta-carbolines by intramolecular electrocyclization-elimination reactions of 2-alkylidene-3-iminoindoles was developed. It was shown that delta-carbolines selectively bind to triplex or duplex DNA (intercalation). Indirubine analogues were prepared by deprotection and lactonization of functionalized 2-alkylidene-3-iminoindoles.

Reversed flow injection and sandwich sequential injection methods for the spectrophotometric determination of copper(II) with cuprizone

Two new flow methods, flow injection analysis (FIA) and sequential injection analysis (SIA), for the spectrophotometric determination of Cu(II) in water at trace levels have been developed and optimised. Both methods are based on the reaction with oxalic acid bis(cyclohexylidene hydrazide) (cuprizone) in alkaline media. The two procedures have been developed for the final aim to compare their performances and to offer new rapid heavy metals analysis tools, avoiding the use of extraction steps. A detailed study of the physico-chemical parameters affecting the systems performances has been carried out. The reversed FIA and sandwich SIA approaches offered the best sensitivity. In both cases, an extremely good linearity has been obtained within the range 0.06–4 μg ml −1 (correlation coefficient r=0.9999), whereas the observed detection limits were 0.013 and 0.004 μg ml −1, for FIA and SIA, respectively. Furthermore, due to the great similarity of the diffusion zones in the reaction slugs, our approach offers the opportunity to compare the two methods in analogous conditions. This SIA method, besides keeping its typical reagent saving features, offered analytical performances equivalent to those of FIA. To obtain these results, an original “stop-flow like” method was successfully employed in the SIA approach. Both methods were validated by analysis of real water samples, after copper addition, and certified reference samples of fortified and waste waters.

Synthesis of Unsymmetrical Pyrrolo[3,2-b]pyrrole-2,5-diones

The first unsymmetrical oxalic acid-bis(imidoyl)dichlorides were prepared and applied to the one-pot synthesis of the first unsymmetrical pyrrolo[3,2-b]pyrrole-2,5-diones and 2,2′-bis-quinazolin-4-ones.

Synthesis of Bis- and Tris(indolinylidenemethyl)benzenes by One-Pot Reactions of Polylithiated Nitriles with Bis(imidoyl)chlorides of Oxalic Acid

The reaction of polylithiated di- and tricyanomethylbenzenes with oxalic acid-bis(imidoyl)chlorides afforded novel oligo(indolinylidenemethyl)benzenes with the formation of up to six carbon-carbon bonds. The UV/Vis spectroscopic features of these and related compounds were studied. 1,4-Disubstituted benzenes containing a large π-system have been efficiently prepared by the reaction of dianions with 1,4-dicyanobenzene. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).

One-Pot Synthesis of Functionalized Indoles by Cyclization of Lithiated Amides and Nitriles with Oxaldiimidoyl Dichlorides

The reaction of the dianion of phenylacetonitrile with substituted oxalic acid bis(imidoyl)chlorides resulted in the formation of 2-alkylidene-3-iminoindoles, containing substituents at different positions of the heterocyclic nucleus. The cyclization of lithiated amides with bis(imidoyl)chlorides afforded (3-imino-2,3-dihydro-1H-indol-2-ylidene)acetic amides. Excellent regio- and E-diastereoselectivities were observed in all reactions.

Synthesis of radialene-shaped pyrroles by multiple-anion-capture reactions of 1,3-dianions.

A new multicomponent reaction (multiple-anion-capture reaction) of 1,3-dianions with nitriles and oxalic acid-bis(imidoyl)chlorides is reported. This process allows for an efficient and regioselective synthesis of a variety of radialene-shaped pyrroles which constitute structurally new and interesting heterocyclic systems. The cyclization products can be considered as aza-analogues of the pharmacologically relevant substance class of 3-acetyltetramic acids. A rationalization of the experimental results is given based on quantum chemical computations.

Regio- and Diastereoselective Synthesis of N-Aryl-5-alkylidene-5H-pyrrol-2-ones by a new Domino Reaction of 1,3-Dicarbonyl Dianions with Oxalic Acid-bis(imidoyl)chlorides

Regio- and Diastereoselective Synthesis of N-Aryl-5-alkylidene-5H-pyrrol-2-ones by a new Domino Reaction of 1,3-Dicarbonyl Dianions with Oxalic Acid-bis(imidoyl)chlorides

Stereoselective Synthesis of 2-Alkylidene-3-iminoindoles by Reaction of 1,1-Dianions with Oxalic Acid Bis(imidoyl) Chlorides

Treatment of dilithiated nitriles and sulfones with oxalic acid bis(imidoyl) chlorides resulted in a new cyclization reaction which provided a variety of (3-imino-2, 3-dihydro-1H-indol-2-ylidene)acetonitriles and -sulfones in good yields. The reactions proceeded by condensation of the dianions with the first imidoyl chloride group of the bis(imidoyl) chloride, subsequent intramolecular attack of the ortho carbon of the arylimino group onto the second imidoyl chloride group, and final aromatization. Excellent stereoselectivities were observed in most cases.

Efficient Synthesis of Quinazolin-4-ones and Axially Chiral 2,2′-Bisquinazolin-4-ones by Reaction of Anthranilic Acid Derived Nucleophiles with Oxalic Acid-Bis(imidoyl)chlorides

Efficient Synthesis of Quinazolin-4-ones and Axially Chiral 2,2′-Bisquinazolin-4-ones by Reaction of Anthranilic Acid Derived Nucleophiles with Oxalic Acid-Bis(imidoyl)chlorides

Regioselective Synthesis of 5-Ylidenepyrrol-2(5H)-ones by Reaction of Transition Metal-Coordinated Bis(imidoyl) Chlorides with Carbon Nucleophiles

A regioselective transition metal mediated domino reaction of carbon nucleophiles with oxalic acid-bis(imidoyl)chlorides is reported. This reaction provides a convenient access to E-configured 5-yl...

Off-line dansylation of amines using C 18 solid-phase packings: study of the fluorescence and chemiluminescence detection by post-column derivatization with oxalic acid bis(2, 4, 6-trichloro phenyl ester)/H 2O 2 in liquid chromatography. Determination of amphetamines in urine samples

Dansylation of amines (primaries and secondaries) using C 18 solid-phase supports is described. The time of analysis and the handing sample have been markedly improved with respect to those required for solution dansylation. The dansylated amine derivates were injected onto the liquid chromatography system and fluorescence detected. The sensitivity and selectivity is better than the other dansylation procedures described in the literature and also better than other derivatization reagents such 1,2-napthoquinone 4-sulfonate (NQS) or 3,5-dinitrobenzoyl chloride (3,5-DNB). Dansyl compounds can also form chemiluminescent derivatives, therefore a post-column derivatization procedure with oxalic acid bis(2, 4, 6-trichloro phenyl ester) (TCPO) and H 2O 2 has been tested As an example of application, the derivatization procedures (pre- and post-column derivatization) have been applied for the determination of amphetamine or methamphetamine with its metabolite amphetamine, in urine samples at the μg/l levels, by using β-phenylehylamine as internal standard.

Aryl-(4-arylimino-4H-pyrido[1,2-a]pyrazin-3-yl)amine-Synthese, Komplexbildung mit Molybd�n(0) und Oxigenierung

Aryl-(4-arylimino-4H-pyrido[1,2-a]pyrazine-3-yl)amines-Synthesis, Complex Formation with Molybdenum(0) and Oxygenation The synthesis of p-tolyl(4-p-tolylimino-4H-pyrido [1,2-a]pyrazine-3-yl)amine 8 (TTPPA) is achieved by the reaction of 2-pyridylmethylamine with oxalic acid bis(p-tolylimidoyl)chloride. The ion-pair [Na(THF)3][(TTPPAH)Mo(CO)4] 4 is obtained by the reaction of the NH-acidic compound 8 with sodium bis(trimethylsilyl)amide and (nor)Mo(CO)4 (nor = norbornadiene) dissolved in THF. The bidentate ligand anion TTPPA-H is related to the 1,4-diazadienes, but its n-donor effect is dominating. Its trans-influence results in different Mo-CO-bond lengths of 4 : 1.901 and 1.951 A (trans-positions); 2.003 and 2.031 A (cis-positions). In the cationic part of 4 the sodium is five-coordinate (distorted tetragonal pyramidal structure). Donor atoms are the three THF, N3 of TTPPA-H, and the oxygen atom of one CO of the moiety Mo(CO)4. 8 is oxygenated by hydrogen peroxide or by dioxygen on heating. In the course of a ring transformation of the 6-membered pyrazine to the 5-membered imidazole cycle 3-p-tolyl-5-p-tolylimino-2-pyridine-2-yl-2,3-dihydro-imidazol-4-one 9 is formed. In THF two isomers 9 and 9a are observed in a molar ratio of about 1:1. 4 and 9 have been characterized by single crystal x-ray diffraction.

ChemInform Abstract: Preparation of P‐Chloro‐Substituted N,N′‐Dimethylurea‐Bridged Diphosphorus Compounds, Their Dehalogenation with Oxalic Acid Bis(trimethylsilyl) Ester and Subsequent Oxidation with Tetrachloro‐o‐benzoquinone.

ChemInformVolume 20, Issue 38 Organoelement Compounds ChemInform Abstract: Preparation of P-Chloro-Substituted N,N′-Dimethylurea-Bridged Diphosphorus Compounds, Their Dehalogenation with Oxalic Acid Bis(trimethylsilyl) Ester and Subsequent Oxidation with Tetrachloro-o-benzoquinone. R. VOGT, R. VOGT Inst. Anorg. Anal. Chem., TU, D-3300 BraunschweigSearch for more papers by this authorR. SCHMUTZLER, R. SCHMUTZLER Inst. Anorg. Anal. Chem., TU, D-3300 BraunschweigSearch for more papers by this author R. VOGT, R. VOGT Inst. Anorg. Anal. Chem., TU, D-3300 BraunschweigSearch for more papers by this authorR. SCHMUTZLER, R. SCHMUTZLER Inst. Anorg. Anal. Chem., TU, D-3300 BraunschweigSearch for more papers by this author First published: September 19, 1989 https://doi.org/10.1002/chin.198938279AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume20, Issue38September 19, 1989 RelatedInformation

Über die Darstellung von P-Chlor-substituierten Ν,N′-Dimethylharnstoff-verbrückten Diphosphorverbindungen, deren Enthalogenierung mit Oxalsäurebis(trimethylsilylester) und anschließende Oxidation mit Tetrachlororthobenzochinon / Preparation of P-Chloro-Substituted N′,N′-Dimethylurea-Bridged Diphosphorus Compounds, their Dehalogenation with Oxalic Acid Bis(trimethylsilyl) Ester and Subsequent Oxidation with Tetrachloroobenzoquinone

Reaction of N,N′-dimethyl-N,N′-bis(trimethylsilyl)urea (1) with dichlorophosphines. RPCl2 (R = Et: 14; R = Pr: 15) has furnished the P-chloro-substituted acyclic diphosphorus compounds, 16 and 17. In the analogous reaction of 1 with Ph2PCl the corresponding bis(diphenylphosphino)-substituted derivative, 21 was formed. Dehalogenation of 11, 16 and 17 with oxalic acid bis(trimethylsilyl) ester, 22 has produced the mixed-valent cyclic λ3P,λ4P-diphosphorus compounds, 23-25 in almost quantitative yield. Oxidation of the λ3P atom in 23-25 with tetrachloroorthobenzoquinone, 26 has given rise to partial cleavage of the P-P bond, and only moderate yields of the products, 29, 31 and 32, have been obtained. The characterization of the various compounds obtained rests, especially, on their 1H and 31P NMR spectra, and on a study of their mass spectral fragmentation pattern