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.     

Reaction of 2,3-Dichloro-1,4-naphthoquinone with Some Active Methylene Compounds in Different Basic Media

Reaction of 2,3-dichloro-1,4-naphthoquinone with some active methylene compounds, such as malononitrile and cyanoacetamide, under various basic conditions has been investigated. A mechanism for these reactions is proposed.     

Synthesis and Crystal Structure of 2,3-Bis(dinitrofluoromethyl)-1,4-dioxane

For the first time the dinitromethyl group was modified to dinitrofluoromethyl group in the series of aliphatic polynitro compounds in the case of the reaction of 1,1,4,4-tetranitro-2,3-butanediol diacetate with ammonium fluoroxysulfate in the presence of sodium bicarbonate and ethylene glycol. Previously unknown 2,3-bis(dinitrofluoromethyl)-1,4-dioxane was synthesized. Its structure was determined by X-ray diffraction analysis.     

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     

Synthesis, spectral and electrochemical characterization of novel 2-(fluoroanilino)-1,4-naphthoquinones

The preparation of novel 2-(fluoroanilino)-1,4-naphthoquinones is presented. It takes place under mild conditions by reacting the corresponding fluoroaniline and 1,4-naphthoquinone in the presence of a Lewis acid catalyst with strong oxidation properties such as CeCl₃·7H₂O. This preparation was also investigated under microwave irradiation. All 1,4-naphthoquinone derivatives were characterized by UV-Vis, IR, ¹H and ¹⁹F NMR, MS and cyclic voltammetry, to investigate the effect of the fluoro-substituents on their electronic properties.     

Synthesis and antitumor activity of 6- and 2- （ 1-acyl sulfanylalkyl）-5,8-dimethoxy- 1,4-naphthoquinones

Sixteen novel 6- and 2-（1-acylsulfanylalkyl）-5,8-dimethoxy-l,4-naphthoquinones were designed and synthesized. Their cytotoxicities were evaluated in vitro against BEL-7402, HT-29 and SPC-Al cell lines. The pharmacological results showed that most of the prepared compounds displayed the excellent selectivity for HT-29 cell line. Compound lab exhibited the most potent antitumor activity among the tested compounds.     

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.]     

Chemistry of naphthazarin derivatives 13. Conformational analysis of 3-(alk-1-enyl)-2-hydroxy-1,4-naphthoquinones by quantum chemistry methods

The molecular structures of various conformers of 2-hydroxy-1,4-naphthoquinone; 3-(alk-1-enyl)-2-hydroxy-1,4-naphthoquinones; 2,5,8-trihydroxy-1,4-naphthoquinone; and 3-(alk-1-enyl)-2,5,8-trihydroxy-1,4-naphthoquinones were studied by density functional theory (B3LYP/6-31(d), B3LYP/6-31(d, p)) and ab initio (MP2/6-31G, MP2/6-31(d)) methods. The strengths of the intramolecular hydrogen bonds formed by the β-hydroxy group with the O atom at C(1) and with the double bond π-electrons of the alkenyl substituents in the quinonoid rings were estimated. The compounds studied mainly exist as rotamers with the former-type hydrogen bonds. The splitting of the quinonoid bands of the stretching vibrations of the β-hydroxy group in the IR spectra of 3-(alk-1-enyl)-2-hydroxy-1,4-naphthoquinones and 3-(alk-1-enyl)-2,5,8-trihydroxy-1,4-naphthoquinones in hexane solutions is due to the existence of rotamers formed upon internal rotation of the alkenyl substituent. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1667–1673, October, 2006.     

Synthesis of 2,3-bis(perfluoroalkyl)quinoxalines and 2,3-bis(perfluoroalkyl)-1,4-benzoxazines from oxides of internal perfluoroolefins

The reactions of oxides of internal trans-, cis-perfluoroolefins with o-phenylenediamine and 2-aminophenol in dioxane gave 2,3-bis(perfluoroalkyl)quinoxalines and 2,3-bis(perfluoroalkyl)-2H-1,4-benzoxazin-2-ols respectively in yields of 23-67%. When N,N-dimethylacetamide was used as a solvent an anionic isomerization of the oxides into ketones, which further yielded 2-(perfluoroalkyl)benzimidazoles in the case of o-phenylenediamine and 2-hydroxy-N-perfluoroalkanoylanilines in the case of 2-aminophenol, became the main path of these reactions. Unusual cyclization resulting in 2-pentafluoroethyl-2-pentafluoropropanoylbenzoxazolidine occurs on interaction between dodecafluoro-3,4-epoxyhexane and 2-aminophenol in N,N-dimethylacetamide.     

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。     

Preparation of Pseudo-Arsonolipids: Dl-2,3-Diacyloxybutane-1,4-Bis(Arsonic Acids)

Abstract

The title pseudo-arsonolipid with palmitoyl side chain has been prepared in ～70% yield from its parent DL-2,3-dihydroxybutane-1,4-bis(arsonic acid) after reduction of the As(V) to As(III) by thiophenol, acylation with palmitoyl chloride in the presence of pyridine and catalytic amounts of 4-(dimethylamino)pyridine, and reoxidation of As(III) to As(V) by hydrogen peroxide. In CDCl₃/CD₃OD esterification of the –AsO₃H₂ groups was detected by ¹H NMR.     

Ytterbium(III) triflate catalyzed annulation of propargylic 1,4-diols with aryl sulfonamides to give highly substituted pyrrole derivatives

A synthetic route to prepare highly substituted pyrrole derivatives efficiently in moderate to good yields via the Yb(OTf)₃-catalyzed cyclization of 1,4-propargylic diols with aryl sulfonamides is reported herein. The present synthetic method offers an operationally simple and convenient route to pyrroles under mild conditions that does not require the exclusion of air and moisture.     

Photolysis of 2-dialkylamino-3-amino(or alkylamino)-1,4-naphthoquinones

Using¹H and¹³C NMR spectroscopy, naphthodihydroimidazolediols were identified as the primary products of photolysis of 2-dialkylamino-3-amino(alkylamino)-1,4-naphthoquinones. Their further non-photochemical (thermal) transformations depend on their structure and on the photolysis conditions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 358–362, February, 1993.     

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     

The chemistry of naphthazarine derivatives

Based on IR and¹H and¹³C NMR spectroscopic studies, the oxidation product of echinochrome with Ag₂O was assigned the structure of 2,3-epoxy-7-ethyl-2,3-dihydro-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone. For part 4, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1607–1609, August, 1999.     

新型氯化三苯基锡(1,4-二氢-2,3-二苯基四氮唑酮)配合物的合成及其性能

以三苯基氯化锡和二苯碳酰二肼为原料,在乙醇-钠中反应合成了一个新型的氯化三苯基锡(1,4-二氢-2,3-二苯基四氮唑酮)配合物（1）,其结构经FT-IR,元素分析和X-射线单晶衍射表征。结果表明：1（CCDC: 1 445 377）属单斜晶系,P21/c空间群,晶胞参数a=1.393 2(6) nm, b=1.097 3(5) nm, c=1.933 7(8) nm, β=110.219(9) ,V= 2.77 4(2) nm³, Z=4, Dc=1.498 g·cm^-3, F(000)=1 264, R₁=0.028 8, wR₂=0.064 6。中心Sn为五配位三角双锥构型。研究了1的荧光性质、热稳定性、电化学性质和体外抗癌活性。结果表明:1在100 ℃下较稳定; 1在400 nm(λ_ex=320 nm)处有弱荧光峰;c(1)=5 μg·mL^-1时,对HeLa细胞株增殖的抑制率为93.70%。     

Reaction of 2-bromomethyl-1,3-thiaselenole with thiourea: en route to the first representatives of 2-(organylsulfanyl)-2,3-dihydro-1,4-thiaselenines

The regioselective reaction of 2-bromomethyl-1,3-thiaselenole 1 with thiourea is accompanied by rearrangement, expanding the ring to afford the corresponding six-membered isothiuronium salt, 2-[amino(imino)methyl]sulfanyl-2,3-dihydro-1,4-thiaselenine hydrobromide 2, a synthon of the 2,3-dihydro-1,4-thiaselenin-2-ylthiolate anion. The latter was used for the synthesis of the first representatives of 2-(organylsulfanyl)-2,3-dihydro-1,4-thiaselenines 3a–g, bis(2,3-dihydro-1,4-thiaselenin-2-yl) disulfide 5 and 1,6-bis(2,3-dihydro-1,4-thiaselenin-2-ylsulfanyl)hexane 6.