EDA Complexes of 2,3-Dichloro-1,4-naphthoquinone with Some Substituted Anilines

Summary. Electron donor-acceptor (EDA) complexes of several substituted anilines with the -acceptor 2,3-dichloro-1,4-naphthoquinone (DClNQ) in chloroform, dichloromethane, and 1,2-dichloroethane were studied by a spectrophotometric method. Experimental data has been shown to confirm the 1:2 stoichiometry of the acceptor-donor in spite of the apparent linearity of the Benesi-Hildebrand plot for a 1:1 complex. The calculated values of oscillator strengths, transition moments, and thermodynamic parameters confirms the 1:2 (A:D) stoichiometry of the complexes. The formation constants and molar absorptivities for these AD₂ complexes have been evaluated. The stoichiometry was unaffected by the variation of the temperature over a small interval and also by the change in polarity of the solvent. The order of the donor strength followed the sequence: N-benzylaniline>p-chloroaniline>m-chloroaniline>o-chloroaniline.Present address: Materials Research Centre, Indian Institute of Science, Bangalore-12, India     

精氨酸与2,3-二氯-5,6-二氰-1,4-苯醌的荷移反应研究

用分光光度法研究了精氨酸与2,3-二氯-5,6-二氰-1,4-苯醌(DDQ)的荷移反应。实验表明,在硼砂溶液中,精氢酸与DDQ在室温下反应30min可获得稳定的络合物,其组成比为2∶1,λmax=342nm,表观摩尔吸光系数ε=1.65×104 L.mol-1.cm-1,线性范围为2～30μg/mL。应用拟定的方法测定了盐酸精氨酸注射液的含量,结果与文献方法一致,回收率在97.2%～98.1%之间,相对标准偏差小于3.1%。     

EDA Complexes of 2,3-Dichloro-1,4-naphthoquinone with Some Substituted Anilines

Electron donor-acceptor (EDA) complexes of several substituted anilines with the -acceptor 2,3-dichloro-1,4-naphthoquinone (DClNQ) in chloroform, dichloromethane, and 1,2-dichloroethane were studied by a spectrophotometric method. Experimental data has been shown to confirm the 1:2 stoichiometry of the acceptor-donor in spite of the apparent linearity of the Benesi-Hildebrand plot for a 1:1 complex. The calculated values of oscillator strengths, transition moments, and thermodynamic parameters confirms the 1:2 (A:D) stoichiometry of the complexes. The formation constants and molar absorptivities for these AD₂ complexes have been evaluated. The stoichiometry was unaffected by the variation of the temperature over a small interval and also by the change in polarity of the solvent. The order of the donor strength followed the sequence: N-benzylaniline>p-chloroaniline>m-chloroaniline>o-chloroaniline.     

Synthesis and Spectral and Electrochemical Characterization of Novel Substituted 1,4-Naphthoquinone Derivatives

The novel substituted 2,3-dichloro-1,4-naphthoquinone derivatives were synthesized from the reactions of (1) and related nucleophilles in sodium carbonate (Na₂CO₃) solution of ethanol, chloroform with Et₃N, or potassium carbonate (K₂CO₃) solution of acetonitrile. The structures of novel compounds were characterized by using microanalysis, Fourier transform–infrared, ¹H NMR, ¹³C NMR, mass spectrometry, and cyclic voltammetry (CV).

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]     

Reaction of 2-chloro-3-(4-N,N-dimethylaminoanilino)-1,4-naphthoquinone with cyclic amines (piperidine,morpholine, and pyrrolidine)

It was shown that the reaction of 2-chloro-3-(4-N,N-dimethylaminoanilino)-1,4-naphthoquinone with piperidine in the absence of a solvent gives not only a product of replacement of the chlorine atom by a piperidino group, 3-(4-N,N-dimethylaminoanilino)-2-piperidino-1,4-naphthoquinone, but also 2-(4-N,N-dimethylaminoanilino)-1,4-naphthoquinone and 2-(4-N,N-dimethylaminoanilino-2-piperidino)-1,4-naphthoquinone. The latter compounds are the only reaction products formed in dimethyl sulfoxide. The reaction with morpholine occurs in a similar way, whereas that with pyrrolidine gives only a product of replacement of the chlorine atom by hydrogen.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2451–2454, December, 1995.     

4-Hydroxy-2-quinolones 119. Reaction of ethyl 1-R-4-chloro-2-oxo-1,2-dihydroquinoline-3-carboxylate with malononitrile

In acid medium ethyl 1-R-4-dicyanomethyl-2-oxo-1,2-dihydroquinoline-3-carboxylates are hydrated in the ketenimine tautomer form exclusively to the corresponding quinolylcyanoacetamides. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 856–863, June, 2007.     

Studies on Charge-Transfer Complexes of 2,3-Dicyano-1,4-naphthoquinone with Some Ring and <Emphasis Type="Italic">N</Emphasis>-Substituted Anilines

Summary. The charge-transfer complexes (CT-complexes) between 2,3-dicyano-1,4-naphthoquinone (DCNQ) and some aromatic anilines, both ring and N-substituted, were studied spectrophotometrically in three chlorinated solvents, viz. chloroform, dichloromethane, and 1,2-dichloroethane at different temperatures. All the donors are known to form stable 1:1 stoichiometric complexes with DCNQ and their stoichiometry was unaffected by the variation of temperature over the studied range. The change in polarity of the solvent also doesnt affect the stoichiometry of the complexes. The determined formation constant values are in the range of 0.49–10.8dm³mol^–1, the highest is for the N-benzylaniline and the lowest is for o-chloroaniline. The effect of functional groups on the aniline moiety towards the strength and its electron releasing property has been discussed. The H, S, and G values are all negative, so the studied complexes are reasonably stable and exothermic in nature. The ionization potentials of the donors were determined using the charge-transfer (CT) absorption bands of the complexes. The dissociation energies (W) of the charge-transfer excited state for the CT-complexes were also determined and are found to be constant.Present address: Materials Research Centre, Indian Institute of Science, Bangalore-12, India     

Synthesis of Mixed Aryl 2,3-Diarylsulphanyl-1,4-naphthoquinones

The reaction of 2-arylsulphanyl-1,4-napththoquinone with aromatic thiols and sodium dithionate leads to bis-2,3-(arylsulphanyl)naphthalene-1,4-diols in high yield. Corresponding oxidized products, namely 2,3-diarylsulphanyl-1,4-naphthoquinones, are prepared in near quantitative yield by a copper(II)-catalyzed aerial oxidation reaction of bis-2,3-(arylsulphanyl)naphthalene-1,4-diols under mild condition.     

Spectrophotometric titration of phenothiazines using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone

A specific Spectrophotometric titration method is described for the micro-determination of some phenothiazine derivatives in strong orthophosphoric acid medium using the -acceptor 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as a mild oxidizing titrant. The wavelengths of maximum absorption of the formed phenothiazonium cation radicals are 500, 515, 530, 533 and 650 nm for trifluoperazine dihydrochloride, promethazine hydrochloride, prochlorperazine dimaleate, chlorpromazine hydrochloride and thiethylperazine dihydrochloride, respectively. Quantitative recoveries are reported for pure drugs and their dosage forms. The method is simple and specific for determining phenothiazine derivatives in presence of their induced degraded oxidation products.     

Reactions of Substituted Indoles with 2,3-Dichloro-1,4-naphthoquinone and Electrochemical Properties of Some 2,3-Substituted 1,4-Naphthoquinones

Russian Journal of Organic Chemistry - The reactions of 2,3-dichloro-1,4-naphthoquinone with some indoles and thiols were investigated. The resulting nucleophilic substitution products were...     

Potentiometric studies on the chelation behaviour of lanthanons with 3-hydroxy-2-methyl-1,4-naphthoquinone (HMNQ)

The chelation behaviour of complexes of La(III), Pr(III), Nd(III), Y(III), Sm(III) and Tb(III) with 3-hydroxy-2-methyl-1,4-naphthoquinone has been studied potentiometrically in 75% (v/v) aqueous dioxan medium at various ionic strengths. The method ofBjerrum andCalvin, as modified byIrving andRossotti, has been used to find values of andpL. The stability constants and the values ofS _min have been calculated. The order of stability constants was found to be: La<Pr<Nd<Sm<Tb.

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Potentiometrische Untersuchungen des Komplexierungsverhaltens von Lanthanid-Ionen mit 3-Hydroxy-2-methyl-1,4-naphthochinon (HMNQ)

Zusammenfassung Das Komplexierungsverhalten der Komplexe von La(III), Pr(III), Nd(III), Y(III), Sm(III) und Tb(III) mit 3-Hydroxy-2-methyl-1,4-naphthochinon wurde potentiometrisch in 75% (v/v) wäßrigem Dioxan bei verschiedenen Ionenstärken untersucht. Die Methode vonBjerrum undCalvin in der Modifikation nachIrving undRossotti wurde zur Bestimmung der Werte für undpL benutzt. Es wurden die Stabilitätskonstanten und dieS _min -Werte berechnet; die Stabilitätskonstanten ergaben folgende Reihung: La<Pr<Nd<Sm<Tb.

     

Diels-Alder Reactions of 5,8-Ethano-5,8-dihydro-1,4-naphthoquinone with Cyclic Dienes

Diels-Alder cycloadditions of 1,3-cyclohexadiene and cyclopentadiene to π -facially dissymmetric 5,8-ethano-5,8-dihydro-1,4-naphtboquinone (1) were examined. The stereochemical outcome of the reactions, determined by a combination of chemical and spectral methods, indicates that addition of cyclic dienes to 1 occurs preferentially at the face syn to the etheno-bridge of 1. Cycloadducts 7a/7b and 8a/8b obtained from Diels-Alder reactions of 1 with cyclopentadiene and 1,3-cyclohexadiene undergo [2+2]-photocyclization to give caged compounds 9a/9b and 10a/10b , respectively. Stereoselective reduction of the enedione double bond in 7a/7b and 8a/8b with aqueous TiCl₃ in acetone affords cis-bis-bicyclic ring-fused 1,4-cyclo-hexadiones 11a/11b , and 12a/12b , respectively.     

Reaction of acetylated 1,4-naphthoquinone thioglucosides with nucleophilic reagents

Acetylated thioglucosides of the 1,4-naphthoquinone series readily undergo heterocyclization into linear tetracyclic 2,3-(2-oxy--D-glucopyranosyl-1-thio)-1,4-naphtho-quinone under the action of McONa/MeOH. The treatment of these thioglucosides with NH₃/MeOH affords 2-amino-3-(giucopyranosyl-1-thio)-1,4-naphthoquinone.Translated from Iz vestiya Akademii Nauk. Seriva Khimicheskava, No. 2, pp. 477–479, February, 1996     

两种含杂环的氨基萘醌化合物的合成

以2,3-二氯-1,4-萘醌为主要原料,分别与吗啡啉和糠胺在一定条件下反应生成2种含杂环的氨基萘醌类化合物。2,3-二氯-1,4-萘醌与吗啡啉及2,3-二氯-1,4-萘醌与糠胺物质的量比均为1∶2,反应温度为60℃,溶剂为乙醇。2,3-二氯-1,4-萘醌与吗啡啉反应时间为1 h,产物2-氯-3-吗啡啉基萘-1,4-二酮(a)收率为93.5%;2,3-二氯-1,4-萘醌与糠胺反应时间为4 h,产物N~2,N~3-二(2-呋喃甲基)-1,4-二((2-呋喃甲基)亚胺)-1,4-二氢化萘-2,3-二氯化铵(d)收率为46.7%。对产物进行IR、Uv、MS和H-NMR等分析表征。     

Synthesis and structure elucidation of oxidative coupling products of 2-hydroxy-1,4-naphthoquinones

2,3-Dihydro-3-O-(1,4-naphthoquinon-2-yl)-2-oxo-1,4-naphthoquinones are the products of oxidative coupling of substituted 2-hydroxy-1,4-naphthoquinones (regardless of the presence of peri-hydroxy groups in their structures) under the action of lead dioxide. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 294—298, February, 2006.     

Oxidative transformation of the natural lignan hydroxymatairesinol with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone

The oxidative transformation of the two isomers of the natural lignan hydroxymatairesinol from Norway Spruce (Picea abies) by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), has been studied. Significant differences in the outcome of the reactions were observed when the pure isomers of hydroxymatairesinol were reacted with DDQ under the same conditions. The different stereoelectronic effects in the two isomers as well as their conformational structures seem to determine the site of reaction, which results in different reaction products. Several products were identified by GC-MS and NMR spectroscopy. Oxomatairesinol was obtained in a yield of 25%.     

Effect of Microwave Irradiation on Reaction of Arylaldehyde Derivatives with Some Active Methylene Compounds in Aqueous Media

Abstract

The effect of microwave irradiation on the condensation reactions of arylaldehydes 1 and active methylene compounds 2 in aqueous media was studied and compared with “classical” conditions. The results show that the condensation was carried out only under microwave irradiation in the presence of ammonium chloride as a catalyst, followed by dehydration, to afford (E)‐olefins 3. The protocol was used to synthesize coumarins by a condensation reaction of salicylaldehyde or its derivatives with various derivatives of ethylacetate 5 (e.g., R³CH₂CO₂Et; R³: CO₂Et, CO₂Me, COMe, CN) in high yields. These investigations will contribute to the development of environmentally friendly and inexpensive processes in organic synthesis.     

BMIMBF4中2-氨基-3-氯-1,4-萘醌电化学捕获CO2的机理

利用循环伏安法（CV）和现场红外光谱电化学技术研究了2-氨基-3-氯-1,4-萘醌（ACNQ）在1-丁基-3-甲基咪唑四氟硼酸盐（BMIMBF₄）中电化学捕获CO₂的机理.研究结果表明,当体系中不存在CO₂时,ACNQ在BMIMBF₄中经历可逆的两步一电子过程;当体系中引入CO₂时,电化学还原过程中形成的二价阴离子（ACNQ^2-）作为亲核试剂,可攻击CO₂的亲电子碳中心,形成稳定的CO₂加合物.对电化学捕获CO₂的化学计量进行了评估,结果表明,1摩尔的ACNQ^2-可捕获1摩尔的CO₂.结合B3LYP方法在6-311++G^**水平上计算分析了反应中CO₂加合物可能的结构.