- A NOVEL SRN1 SUBSTITUTION: THE REACTION BETWEEN THE ANION OF 2-NITROPROPANE AND 3-BROMO-1-NITROCYCLOHEX-1-ENE
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X-ray crystallography has been used to determine the unusual cyclopropyl structure for the product of the SRN1 reaction between the anion of 2-nitropropane and 3-bromo-1-nitrocyclohex-1-ene.
- Bowman, W. Russel,Brown, David S.,Leung, Christina T. W.,Stutchbury, Andrew P.
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- Polynitro-Substituted Strained-Ring Compounds. Synthesis, Mechanism of Formation, and Structure of trans-Dinitrocyclopropanes
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1,2-Dinitrocyclopropane, 1,2-dimethyl-1,2-dinitrocyclopropane, and 1,2-diethyl-1,2-dinitrocyclopropane have been prepared in 23-36percent yield by oxidative cyclization of the corresponding open-chain 1,3-dinitronate dianions with iodide in DMSO.In each case only the trans isomer of the dinitrocyclopropane was obtained.Treatment of 2,4-dibromo-2,4-dinitropentane with the lithium salt of 2-nitropropane gave trans-1,2-dimethyl-1,2-dinitrocyclopropane, suggesting the intermediacy of a halonitro nitronate intermediate in the oxidative cyclization process.Further mechanistic studies using m-dinitrobenzene suggest either an internal single-electron transfer, nonchain pathway or an internal SN2 process leading to the dinitrocyclopropanes.An X-ray crystallographic study performed on trans-1,2-dinitrocyclopropane indicates substantially shortened distal C-C bonds (1.47 Angstroem) and bisected conformations for each nitro group.Ab initio calculations using a 4-31G basis set are in agreement with the X-ray data, except longer distal C-C bonds (1.49 Angstroem) are calculated.Ab initio calculations using a variety of basis sets were performed on nitrocyclopropane as a model.
- Wade, Peter A.,Dailey, William P.,Carroll, Patrick J.
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- Consecutive SRN1 and ERC1 Reactions in 5-Nitroisoquinolines
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The reaction of 1-(dichloromethyl)-5-nitroisoquinoline with 2-nitropropane anion which gives 1-isopropylidenemethyl-5-nitroisoquinoline as major product is shown to proceed by the consecutive SRN1 and ERC1 mechanisms.These mechanisms are confirmed by the inhibitory effects of dioxygen, p-dinitrobenzene, cupric chloride and TEMPO.
- Vanelle, Patrice,Rathelot, Pascal,Maldonado, Jose,Crozet, Michel P.
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- Efficient synthesis of a peculiar vicinal diamine semiochemical from streptomyces natalensis
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(Equation Presented). The pimaricin-inducing (PI) factor, produced by Streptomyces natalensis is a proposed pheromone with a peculiar vicinal diamine structure. The first synthesis of this molecule is reported. It features oxidative dimerization of an aci-nitro anion derived from tris(hydroxymethyl) nitromethane and disproportionation catalyst-facilitated hydrogenation of the resulting vicinal tertiary dinitro compound. As the synthesis requires only four steps with no chromatographic separations, it provides a convenient route to prepare PI factor for biological studies and industrial applications.
- Morin, Jesse B.,Sello, Jason K.
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- Alkali metal ion triggered conductive and stimuli-responsive metallogels
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A novel gelator NDH containing naphthalimide substituted with a 4,4,5,5-tetramethylimidazoline-1,3-diol group was synthesized and characterized. Driven by dynamic coordination interactions between the imidazoline-1,3-diol unit and alkali, NDH self-assembled into a wide range of metallogels in pentanol triggered by sonication just at room temperature. The coordination interactions between NDH and Li+ were further certified by 1H NMR and XRD analysis. The gels were characterized by several experiments such as UV–vis, fluorescent, SEM and rheology experiments. Notably, the ion conductivity of Li+/metallogels confirmed that the three dimensional network in the organogels does not affect the ions diffusion in the large interconnected liquid domains. Electrochemical impedance spectroscopy was used to prove that NDH/LiClO4-gel had stronger electrical conductivity than that of NDH/LiCl-gel.
- Chen, Shaorui,Li, Xiaoyuan,Yu, Xudong
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- Nitroxide free radical, and preparation method and application thereof
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The invention relates to a nitroxide free radical, and a preparation method and application thereof. The nitroxide free radical can effectively protect normal lung epithelioid cells of a human body from cell oxidation damage caused by paraquat induction, and has a great potential value for preparing a novel paraquat antidote. The method for preparing the nitroxide free radical has the advantages of mild reaction conditions, simple synthesis steps, easily obtained raw materials, high yield and good reproducibility. Nickel acetate is added into a reaction of aldehyde to serve as a catalyst, so that reaction conditions in the step are greatly reduced, and reaction time is shortened. Meanwhile, purity of a final product is high due to a used novel recrystallization solvent, and the obtained crystal is easy for single crystal diffraction tests.
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Paragraph 0034-0035; 0044-0045
(2020/03/02)
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- Revisiting the Ullman's Radical Chemistry for Phthalocyanine Derivatives
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Phthalocyanine derivatives do not cease to gain attention due to their numerous properties and applications (e.g., sensor, PDT). This makes them a unique scaffold for the design of new material. In this context, we were interested to develop the synthesis of an imino nitroxide-substituted phthalocyanine by Ullman's procedure; a challenge due to the intrinsic low solubility of most phthalocyanine derivative in much solvents. To overcome this solubility problem, we designed a phthalocyanine with bulky neopentyl substituents in peripheral positions as counterpart to the imino nitroxide moieties. The imino nitroxide-substituted phthalocyanine was obtained by condensation of a monoformyl-substituted phthalocyanine with 2,3-bis(hydroxylamino)-2,3-dimethylbutane in refluxing THF–MeOH (2:1) mixture in the presence of p-toluenesulfonic acid monohydrate, follow by oxidation with PbO2. Characterization was performed by electrochemistry, UV/Vis and EPR spectroscopy in solution as well as SQUID in solid state.
- Fidan, Ismail,Luneau, Dominique,Ahsen, Vefa,Hirel, Catherine
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supporting information
p. 5359 - 5365
(2018/02/09)
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- Combination of PhI(OAc)2 and 2-Nitropropane as the Source of Methyl Radical in Room-Temperature Metal-Free Oxidative Decarboxylation/Cyclization: Construction of 6-Methyl Phenanthridines and 1-Methyl Isoquinolines
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A room-temperature metal-free method for generating highly unstable methyl radical was realized from the combination of PhI(OAc)2 and 2-nitropropane, which provides an efficient approach to methylated phenanthridines and isoquinolines. The strategy was also extended to the generation of other alkyl radicals and a concise synthesis of Roxadustat.
- Lu, Shi-Chao,Li, Hong-Shuang,Gong, Ya-Ling,Zhang, Shi-Peng,Zhang, Ji-Guo,Xu, Shu
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p. 15415 - 15425
(2019/01/03)
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- 1-hydroxy-2-(substituted phenyl)-4, 4, 5, 5-tetramethylimidazoline and its synthesis method, activity and use
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The invention discloses 1-hydroxy-2-[3-(formyl-Ala)-4-(oxyacetyl-Gly)phenyl]-4, 4, 5, 5-tetramethylimidazoline and its preparation method, antithrombotic and thrombolytic activity and use in treatment on brain ischemia rats. The invention discloses a use of the 1-hydroxy-2-[3-(formyl-Ala)-4-(oxyacetyl-Gly)phenyl]-4, 4, 5, 5-tetramethylimidazoline in preparation of antithrombotic and thrombolytic drugs and drugs for treatment on ischemic stroke.
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Paragraph 0022; 0023
(2017/06/02)
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- 2-(substituted phenyl)-4,4,5,5-tetramethyl-1-hydroxy-imidazoline, and synthesis, activity and application thereof
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The invention discloses 1-hydroxy-2-[3-(formyl-Gly)-4-(oxyacetyl-Ala) phenyl]-4,4,5,5-tetramethyl imidazoline, a preparation method thereof, antithrombotic activity thereof, thrombolytic activity thereof, and an effect thereof for treating mice suffering from cerebral ischemia. Furthermore, the invention discloses an application of 1-hydroxy-2-[3-(formyl-Gly)-4-(oxyacetyl-Ala) phenyl]-4,4,5,5-tetramethyl imidazoline to preparation of antithrombotic medicaments, thrombolytic medicaments and ischemic-stroke-treating medicaments.
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Paragraph 0022; 0023
(2017/07/01)
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- Laccases for bio-bleaching
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Provided herein are isolated laccase enzymes and nucleic acids encoding them. Also provided are mediators for laccase reactions. Also provided herein are methods for using laccases to oxidize lignins and other phenolic and aromatic compounds, such as for bio-bleaching and decolorization of wood pulp under high temperature and pH conditions to facilitate a substantial reduction in use of bleaching chemicals, as well as for treatment of fibers.
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Page/Page column 27
(2016/06/28)
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- Alpha-tocopherol spin labeling derivatives and preparation method thereof
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The invention discloses alpha-tocopherol spin labeling derivatives of which the structural formula is disclosed in the specification. The invention also discloses a preparation method of the derivatives. By introducing the special-structure pyrrolinenitroxide free radicals into the oxidation-resistant natural product molecules, the method has the advantages of mild derivative synthesis conditions, easy purification for derivatives and high yield.
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Paragraph 0023
(2017/05/10)
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- Synthesis and Straightforward Quantification Methods of Imino Nitroxide-Based Hexaradical Architecture on a Cyclotriphosphazene Scaffold
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The synthesis of a homogeneous neutral hexaradical architecture consisting of six imino nitroxide radical moieties covalently bonded on a cyclotriphosphazene scaffold was reported. The synthesis of hexaradical imino nitroxide compounds follows the Ullman procedure involving the condensation of 2,3-bis(hydroxylamino)-2,3-dimethylbutane with hexa-(4-formylphenoxy)cyclotriphosphazene (3) followed by oxidation of the condensation product hexa-[4-(1-hydroxy-4,4,5,5-tetramethyl-2-imidazoline-2-yl)phenoxy]cyclotriphosphazene (2) by NaIO4. Characterization of hexaradical was performed by X-ray and SQUID in solid state and by EPR, absorption spectroscopy, and electrochemistry in solution. CV of 1 shows an oxidation peak at 1.184 V (vs SCE) and a reduction peak at -0.883 V, both characteristics of the presence of phenyl imino nitroxide (7) moieties, suggesting that the contribution of the cyclotriphosphazene core is negligible. Attention was particularly focused on developing methods, UV-vis spectroscopy and square-wave voltammetry, to quantify the number of radicals in a way to confirm easily and rapidly the polyradicals' structure.
- Fidan, Ismail,?nal, Emel,Yerli, Yusuf,Luneau, Dominique,Ahsen, Vefa,Hirel, Catherine
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supporting information
p. 11447 - 11453
(2016/11/17)
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- NOVEL COMPOUND WITH EFFECTS OF THROMBOLYSIS, FREE RADICAL SCAVENGING AND THROMBUS-TARGETING AS WELL AS PREPARATION METHOD AND USE THEREOF
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The present invention discloses a novel compound with effects of thrombolysis, free radical scavenging and thrombus-targeting, as well as a preparation method and use thereof. The compound is a ternary conjugate formed by conjugating a thrombolytic peptide, a free radical scavenger and a thrombus-targeting/antithrombotic peptide together via a linking arm. The present invention also discloses a pharmaceutical composition containing the compounds, wherein the compounds form a nanospherical structure.
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Paragraph 0089
(2015/11/03)
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- Silver(I)-Promoted ipso-Nitration of Carboxylic Acids by Nitronium Tetrafluoroborate
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A novel and efficient method for the regioselective nitration of a series of aliphatic and aromatic carboxylic acids to their corresponding nitro compounds using nitronium tetrafluoroborate and silver carbonate in dimethylacetamide has been described. This transformation is believed to proceed via the alkyl-silver or aryl-silver intermediate, which subsequently reacts with the nitronium ion to form nitro substances. Mild reaction conditions, tolerant of a broad range of functional groups, and formation of only the ipso-nitrated products are the key features of this methodology when compared to known methods for syntheses of nitroalkyls and nitroarenes.
- Natarajan, Palani,Chaudhary, Renu,Venugopalan, Paloth
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p. 10498 - 10504
(2015/11/18)
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- Selective synthesis of dimethyl ketone oxime through ammoximation over Ti-MOR catalyst
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Titanosilicate with the MOR topology (Ti-MOR), postsynthesized from highly dealuminated mordenite and TiCl4 vapor through a solid–gas reaction, was highly active and selective for the liquid-phase ammoximation of dimethyl ketone (DMK) with ammonia and hydrogen peroxide. The parameters effecting the formation of the ammoximation product of dimethyl ketone oxime were investigated systematically in a batch-type reactor, and the optimized conditions were further applied to continuous ammoximation of DMK in a slurry reactor. Ti-MOR was superior to other titanosilicates in terms of activity and lifetime. TS-1 was not suitable for the ammoximation of DMK, whereas Ti-MWW required a higher catalyst loading to reach a reasonable activity, and they both easily produced a main byproduct of oxidative coupling of dimethyl ketone oxime. The deactivation behavior of Ti-MOR was investigated. Ammonia-induced structural desilication and accompanied Ti sites migration altered a more serious influence on the catalyst duration than coke deposition during continuous ammoximation.
- Ding, Jianghong,Wu, Peng
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- Oxidative bromination of alkenes mediated with nitrite in ionic liquids
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The oxidative bromination of C2-C8 alkenes with HBr-NaNO2-O2 in solutions of BMImBr, HMImBr or BMImBF 4 containing 16-28 wt% H2O was studied using volumetric method, GC-MS analysis, 14N NMR and UV-VIS spectroscopy. The optimal conditions to conduct the reaction at high selectivity for 1,2-dibromoalkanes in BMImBr were determined. The composition of ionic liquid affects the catalytic performance. Although in BMImBF4 the reaction runs with equal rate as in bromide ionic liquid, the fraction of bromohydrin in the reaction products increases to 20 %. Generated from NaNO2, NOx operated as a catalyst in the oxidation of Br- and was oxidized to catalytically inert NO3 - anions when complete conversion of HBr was attained. Graphical Abstract: Oxidative bromination of alkenes [Figure not available: see fulltext.]
- Kuznetsova, Lidia I.,Kuznetsova, Nina I.,Zudin, Vladimir N.,Utkin, Viktor A.,Trebushat, Dmitry V.,Fedotov, Martin A.,Larina, Tatyana V.
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p. 1499 - 1506,8
(2014/11/08)
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- The mechanism of catalyst deactivation and by-product formation in acetone ammoximation catalyzed by hollow titanium silicalite
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The deactivation mechanism of hollow titanium silicalite (HTS) in aqueous ammoximation of acetone was investigated. Amines and polynitro-compounds, formed by alkaline autocatalytic and oxidative coupling reaction respectively, were determined to be the ma
- Wang, Yi,Zhang, Shengjian,Zhao, Yingxian,Lin, Min
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- METHOD FOR PREPARING 2,3-DIMETHYL-2,3-DINITROBUTANE
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The present invention relates to a method for preparing 2,3-dimethyl-2,3-dinitrobutane (DMNB), which includes the following steps: (1) making titanium-silicate molecular sieve catalyst, acetone, hydrogen peroxide and ammonia contact and react at 65-80° C. to obtain a modified titanium-silicate molecular sieve catalyst; and (2-1) making acetone oxime and hydrogen peroxide contact and react in the presence of the modified titanium-silicate molecular sieve catalyst and water under the conditions of temperature of 60-90° C. and pH of 8-10, and separating DMNB from the reaction products thereof; or (2-2) making acetone, ammonia and hydrogen peroxide contact and react in the presence of the modified titanium-silicate molecular sieve catalyst and water under the conditions of temperature of 60-90° C. and pH of 8-10, and separating DMNB from the reaction products thereof. By the method provided by the present invention, DMNB can be prepared without having to use dangerous chemicals, such as 2-nitropropane, NaH and the like.
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Paragraph 0107; 0108; 0109; 0110; 0111
(2013/07/25)
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- Copper-catalyzed homodimerization of nitronates and enolates under an oxygen atmosphere
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A method for copper-catalyzed oxidative dimerization of nitronates and enolates using oxygen as the terminal oxidant has been developed. Cyclization through oxidative intramolecular coupling is also feasible for both nitronates and enolates. The mild reaction conditions lead to good functional group tolerance.
- Do, Hien-Quang,Tran-Vu, Hung,Daugulis, Olafs
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p. 7816 - 7818
(2013/01/16)
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- Access to original vinylic chlorides in the quinazoline series via a monoelectronic transfer reaction approach
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A series of new quinazoline derivatives bearing a vinylic chloride group on the 2-position was prepared by using a consecutive SRN1 / ERC1 radical strategy. Copyright
- Maillard-Boyer, Martine,Castera-Ducros, Caroline,Verhaeghe, Pierre,Sifredi, France,Rathelot, Pascal,Vanelle, Patrice
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experimental part
p. 2719 - 2729
(2010/07/03)
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- A new class of analgesic agents toward prostacyclin receptor inhibition: Synthesis, biological studies and QSAR analysis of 1-hydroxyl-2-substituted phenyl-4,4,5,5-tetramethylimidazolines
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By studying the structural similarity of analgesic imidazolines and 2-phenylnitronyl nitroxides, 20 1-hydroxyl-2-substituted phenyl-4,4,5,5-tetramethylimidazolines (2a-t) were newly synthesized as selective antagonists of prostacyclin receptor (IP receptor). In the in vivo tail-flick assay, 2a-t (dose, 0.13 mmol/kg) receiving mice showed increased pain thresholds ranging from 20.52 ± 7.25% to 90.94 ± 11.97%, which were significantly higher than that ranged from 12.27 ± 9.56% to 17.71 ± 7.00% shown by normal saline (NS) receiving mice. In the in vivo tail bleeding assay, 2a-t (dose, 1.30 mmol/kg) receiving mice gave a bleeding time ranging from 116.3 ± 8.0 s to 119.6 ± 7.1 s, and NS receiving mice gave a bleeding time ranging from 116.7 ± 7.5 s to 119.1 ± 8.7 s, which were at a substantially equal level. These observations imply that no bleeding risk occurred even when 10-fold dose of analgesic assay was used. In the in vitro vasorelaxation assay, it was found that when the aortic strip contracted by noradrenaline (NE, final concentration, 10-7 M) was treated with the solution of 2a-t in NS (final concentration, 5 × 10-3 M) only lower percentage inhibitions ranged from 6.63 ± 2.72% to 46.28 ± 2.63% were recorded. Relatively higher concentration of 2a-t (5 × 10-3 M) and relatively lower percentage inhibitions (13 of 20 less than 23.27 ± 3.47%) suggest that 2a-t exhibit few vasodilation activity. To shed some light on the potential analgesic mechanisms of 2a-t, moreover, a QSAR analysis was carried out by using the multiple linear regression method. Taken altogether, the current study confirms that as selective antagonist of IP receptor 1-hydroxyl-2-substituted phenyl-4,4,5,5-tetramethylimidazoline may be a promising lead compound of analgesic agent without cardiovascular and bleeding side effects.
- Zhao, Ming,Li, Zheng,Peng, Li,Tang, Yu-Rong,Wang, Chao,Zhang, Ziding,Peng, Shiqi
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p. 1048 - 1058
(2008/09/20)
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- Protective effect of nitronyl nitroxide-amino acid conjugates on liver ischemia-reperfusion induced injury in rats
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Stable nitroxides are potential antioxidant drugs. In this study, we have linked nitroxide to natural amino acids with the aim to improve therapeutic activity. The radical scavenging activities of two nitronyl nitroxide-amino acid conjugates (NNR and NNK) were evaluated in PC 12 cell survival assays. The NO scavenging activities of these compounds were confirmed in the acetylcholine-induced vasorelaxation assay. In addition, the protective effect of NNR was demonstrated in an in vivo rat model of hepatic ischemia-reperfusion (I/R) induced injury and oxidative change. Because NNR reduced hepatic I/R injury by minimizing oxidative stress, it might be possible to develop it into a possible therapeutic agent for hepatic I/R injury.
- Bi, Wei,Cai, Jianhui,Xue, Ping,Zhang, Yanrong,Liu, Sanguang,Gao, Xiang,Li, Meng,Wang, Zhibo,Baudy-Floc'h, Michele,Green, Sarah A.,Bi, Lanrong
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p. 1788 - 1794
(2008/12/20)
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- A class of novel nitronyl nitroxide labeling basic and acidic amino acids: Synthesis, application for preparing ESR optionally labeling peptides, and bioactivity investigations
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Aimed at optional ESR label 2-(4′-hydroxyl)phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl was introduced into the guanido of l-Arg-OH, the ω-amino group of l-Lys-OH with methylcarboxyl as a linker, and into the β-carboxyl of l-Asp-OH and the γ-carboxyl of l-Glu-OH with ethylamino as a linker. It was explored that the synthetic 30 novel ESR labeling amino acid derivatives were stable enough to the reaction conditions of peptide synthesis. Their incorporation led to 12 novel ESR optionally labeling PAK, RGDS, RGDV, and ECG. A series of NO related chemical tests, the in vitro and in vivo assays of these peptides confirmed that this strategy was practical.
- Zhang, Jianwei,Zhao, Ming,Cui, Guohui,Peng, Shiqi
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p. 4019 - 4028
(2008/12/22)
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- BIFUNCTIONAL ACTIVE SITES FOR ADSORPTION OF NOX
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Immobilized nitronyl nitroxide active sites on the surface of a porous inorganic oxide support act as efficient and rapid oxidants for NO, reacting with > 99% of the NO under flow conditions through a packed bed; and, in a parallel configuration with nitroxyl radical active sites, act to remove > 99 % of both NO and NO2 from a gas mixture, with > 95% of the active sites participating in NOx trapping.
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Page/Page column 28
(2008/12/08)
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- Novel 1-oxyl-2-substitutedphenyl-4,4,5,5-tetramethylimidazolines: Synthesis, selectively analgesic action, and QSAR analysis
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Based on the knowledge that imidazoline can result in analgesic action due to its selective binding with the prostacyclin receptor, 20 1-oxyl-2-substitutedphenyl-4,4,5,5-tetramethylimidazolines (3a-t) were prepared in moderate yields. At 0.13 mmol/kg dose, their in vivo analgesic activities were evaluated after the mice were administered at 30, 60, 90, and 150 min. Compared with the pain threshold (12.27 ± 9.56-17.71 ± 7.00%) of normal saline (NS) receiving mice, the pain threshold (23.42 ± 8.14% to 102.58 ± 10.66%) of 3a-t receiving mice increases significantly. Considering a prostacyclin receptor targeting analgesic agent usually had bleeding action and to appraise the bleeding risk, the in vivo tail bleeding time of 1.30 mmol/kg 3a-t receiving mice was found to be ranged from 116.3 ± 8.2 s to 120.3 ± 9.2 s, which was substantially equal to that (117.8 ± 8.4 s to 119.0 ± 8.6 s) of NS receiving mice. Based on the possibility of imidazoline acting as vasodilator, the in vitro vasorelaxations of 3a-t were tested using the rat aortic strip model. When the aortic strip contracted by noradrenaline (NE, final concentration 10-7 mol/l) was treated with 3a-t (final concentration 5 × 10-4 mol/l), only lower percentage inhibitions (6.55 ± 5.70-37.40 ± 4.07%) were recorded, implying that the vasorelaxation of 3a-t was neglectable. By selecting appropriate molecular descriptors generated from e-dragon server, the QSAR model of the analgesic activities of 3a-t was constructed using the multiple linear regression method. The established QSAR model showed reasonable accuracy and thus it is promising to be used for screening new 1-oxyl-2-substitutedphenyl-4,4,5,5-tetramethylimidazoline derivatives as analgesic agents.
- Zhao, Ming,Li, Zheng,Peng, Li,Tang, Yu-Rong,Wang, Chao,Zhang, Ziding,Peng, Shiqi
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p. 2815 - 2826
(2007/10/03)
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- Oxidative nitration of mononitroalkanes in a system sodium nitrite-polyhaloalkane
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In reaction of nitroethane lithium salt with sodium nitrite in DMSO, DMF or HMPA involving polyhaloalkanes 1,1-dinitroethane formed in a high yield. The highest yield was obtained with bromo-and iododerivatives. The reaction fits to a kinetic equation of over all second order: the first with respect to the nitroethane anion, and the first in polyhaloalkane. The rate constants of the process are linearly dependent on the electron affinities of the perhaloalkanes molecules. Nauka/Interperiodica 2007.
- Petrova,Shcherbinin,Bazanov,Tselinskii
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p. 646 - 651
(2008/02/08)
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- Novel 2-substituted nitronyl nitroxides as free radical scavengers: Synthesis, biological evaluation and structure-activity relationship
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To develop more potent small molecules with enhanced free radical scavenger properties, we designed and synthesized a series of nitronyl nitroxide derivatives 4a-h. A lead compound 4f was discovered based on Ach-induced vascorelaxation assay. Further chemical modification based on this scaffold provided a new series of 2-substituted phenylnitronyl nitroxide derivatives 6a-s. The newly synthesized compounds 6a-s possess improved radical scavenger's activity based on PC12 cell survival assay. Compounds 6g,n,o, and s are some of the most potent compounds in terms of NO, H2O2, and OH scavenging ability. 2-Substitued phenylnitronyl nitroxides had a higher radical scavenging activity with the electron-donating group (EDG). In contrast, the introduction of electron-withdrawing group (EWG) to the aromatic ring led to a dramatic decrease in its radical scavenging activity. These results suggest that the electron-donating group (EDG) of the aromatic ring may be an important factor influencing the radical scavenging behavior of these compounds, and the potency of free radical scavenging activity largely depended on the position and electronic properties of the phenyl ring substituents. The enhanced radical scavenging capacities of the novel 2-substituted nitronyl nitroxides may be potential drug leads against the deleterious action of ROS (reactive oxygen species)/RNS (reactive nitrogen species).
- Wu, Yihui,Bi, Lanrong,Bi, Wei,Li, Zeng,Zhao, Ming,Wang, Chao,Ju, Jingfang,Peng, Shiqi
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p. 5711 - 5720
(2007/10/03)
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- Synthesis and biological activity of nitronyl nitroxide containing peptides
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[1-(1′,3′-Dioxyl-4′,4′,5′, 5′-tetramethyldihydroimidazol-2-yl)-phenyl-4-yl]oxyacetic acid (4), a nitronyl nitroxide, and its peptide derivatives, N-[1-(1′,3′-dioxyl- 4′,4′,5′,5′-tetramethyldihydroimidazol-2-yl) -phenyl-4-yl]oxyacetyl-ARPAK (9a), -GRPAK (9b), and -QRPAK (9c), were synthesized and characterized. Judging from the results of electron spin resonance analysis, the newly synthesized nitronyl nitroxide containing peptides, 9a, 9b, and 9c, demonstrated the characteristics of free radicals. The free radical scavenging activities of 9a, 9b, and 9c were assessed using in vitro free radical scavenging tests. The thrombolysis effect of 9a, 9b, and 9c was evaluated using an euglobulin clot lysis test, a fibrinolytic lysis test, and in vivo thrombolysis tests. Results indicated that these nitronyl nitroxide containing peptides possessed both free radical scavenging activity and thrombolytic activity.
- Zhao, Ming,Liu, Junling,Wang, Chao,Wang, Lili,Liu, Hu,Peng, Shiqi
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p. 4285 - 4292
(2007/10/03)
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- Electrooxidative coupling of salts of nitro compounds with halide, nitrite, cyanide, and phenylsulfinate anions
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Electrolysis of salts of primary and secondary nitro compounds (nitroethane, 1- and 2-nitropropanes, nitrocyclohexane, and nitrocycloheptane) in the presence of excess halide, nitrite, cyanide, and phenylsulfinate anions under undivided and divided amperostatic electrolysis conditions in a two-phase medium (CH2Cl2/H2O) produces geminal nitrohalides (35-85% yields), dinitro compounds (15-51%), nitronitriles (6-27%), and nitrosulfones (50-70%). The salts of secondary nitro compounds form the products of oxidative coupling with halide and phenylsulfinate anions under the undivided electrolysis conditions. In all other cases, divided electrolysis is required.
- Ilovaisky,Merkulova,Ogibin,Nikishin
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p. 1585 - 1592
(2007/10/03)
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- Synthesis and bioactivities of nitronyl nitroxide and RGD containing pseudopeptides
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1-(1′,3′-dioxyl-4′,4′,5′,5′- tetramethyldihydroimidazol-2′-yl)-phenyl-4-yloxylacetic acid (3), and 1-(1′,3′-dioxyl-4′,4′,5′,5′- tetramethyldihydroimidazol-2′-yl)-phenyl-4-yloxylacetyl-RGDS (13), -RGDV (14), -RGDF (15) were synthesized. The ESR measurement gave the same spectroscopy for 3 and 13-15. The NO scavenging tests in vitro, anti-platelet aggregation tests in vitro and the anti-thrombosis assay in vivo indicated that introducing 3 into the N-terminal of RGDS, RGDV and RGDF the corresponding bioactivities for both of 3 and RGD peptides can be remained completely. The present combinations provided a beneficial strategy for simultaneous scavenging NO and anti-thrombosis, and for the use of spin label of RGD peptides in the conformational researches.
- Liu, Junling,Zhao, Ming,Wang, Chao,Peng, Shiqi
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p. 4065 - 4069
(2007/10/03)
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- Radical-nucleophilic substitution (SRN1) reactions. Part 7. Reactions of aliphatic α-substituted nitro compounds
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α-Nitrothiocyanates R2C(SCN)NO2 have been prepared by oxidative addition of thiocyanate anion to nitronate anions and undergo SRN1 substitution reactions by loss of thiocyanate with nitronate anions, phenylsulfinate, azide and p-nitro- and p-chloro-benzenethiolates in dipolar aprotic solvents. 2-Nitro-2-thiocyanatopropane and other 2-substituted-2-nitropropanes [Me2C(X)NO2 with X = I, Br, Cl, NO2, PhSO2] react with thiolates by SRN1 reactions and/or redox reactions to give disulfides by a polar abstraction or chain SET (SET2) mechanisms. The products are dependent on the nucleophilicity of the thiolates, the polarisability of the α-substituent, the solvent and the presence of light catalysis, radical traps or strong electron acceptors. 2-Substituted-2-nitropropanes [Me2C(X)NO2 with X = N3, NO2, CN, p-NO2-C6H4-N=N] undergo SRN1 substitutions with thiolates by loss of nitrite. 2-Substituted-2-nitropropanes Me2C(X)NO2 and thiolates only yield disulfides in methanol due to solvation of the nitro groups.
- Al-Khalil,Bowman,Gaitonde,Marley,Richardson
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p. 1557 - 1565
(2007/10/03)
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- Synthesis of c(αα)-unsymmetrically disubstituted nitroesters by electron transfer C-alkylation of ethyl 2-nitropropionate anion
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The ethyl 2-nitropropionate anion was shown to react with six reductive alkylating agents to give new C(αα)-unsymmetrically disubstituted nitroesters and in some cases new ethyl monosubstituted methacrylates. The C- alkylation was shown to proceed by the S(RN)1 mechanism which was confirmed by the classical criteria for S(RN)1 reaction: the electron-withdrawing group effect and classical inhibition experiments by dioxygen, p-dinitrobenzene, cupric chloride or TEMPO. For example, ethyl 2-methyl-2-nitro-3-p- nitrophenylpropionate was transformed in the corresponding amino acid.
- Beraud, Valerie,Perfetti, Patricia,Pfister, Christine,Kaafarani, Mustapha,Vanelle, Patrice,Crozet, Michel P.
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p. 4923 - 4934
(2007/10/03)
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- 2-Bromo-2-nitropropane/Zn promoted reductive cyclizations of ortho-substituted nitroarenes toward 2,1-benzisoxazole derivatives
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Under the mild conditions, reductive cyclizations of 2-nitrobenzaldehydes or 2′-nitroacetophenone towards 2,1-benzisoxazoles were accomplished in the presence of 2-bromo-2-nitropropane/Zn in methanolic solution. The synthetic utility and the role of 2-bromo-2-nitropropane were investigated.
- Kim, Byeong Hyo,Jun, Young Moo,Kim, Tae Kyu,Lee, Yoon Seok,Baik, Woonphil,Lee, Byung Min
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p. 235 - 240
(2007/10/03)
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- Reactions of nitrogen dioxide with hexenes. The mechanistic and structural factors controlling the product composition
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The reaction of nitrogen dioxide with a number of hexenes has been investigated using several solvents and the major products have been identified.The heterolytic reaction path has been effectively eliminated by the use of hexane as solvent.The mechanism of the heterolytic reaction path is discussed with the aid of ab initio molecular orbital calculations on possible nitrosating agents with particular reference to the syn and anti forms of nitrosyl nitrate.A new mechanism is proposed for the formation of certain trisubstituted derivatives.
- Golding, Peter,Powell, Joy L.,Ridd, John H.
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p. 813 - 820
(2007/10/03)
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- ω-Alkenyl α-Nitroalkyl Radicals. Part 3. Radical Chain Reactions of ω-Alkenyl α-Halogenonitroalkanes
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SRN1 reactions between 5-bromo-5-nitrohex-1-ene and the nitronate anions of 2-nitropropane and 5-nitrohex-1-ene failed to give cyclisation of the intermediate α-nitroalkyl radical onto the alkene.Reaction between exo-5-bromo-endo-5-nitro-exo-6-phenylbicyclohept-2-ene 1 and the anion of 2-nitropropane did not undergo an SRN1 reaction and Br+ abstraction gave 2-bromo-2-nitropropane and 5-endo-nitro-exo-6-phenylbicyclohept-2-ene.BNAH reduction of exo-5-bromo-endo-5-nitro-exo-6-phenylbicyclohept-2-ene 1, 6-bromo-6-nitrohept-1-ene, and 1-bromo-1-nitro-2-(prop-2-enyl)cyclohexane gave the corresponding nitroalkanes without any cyclosation of the intermediate α-nitroalkyl radicals.Initial results indicate that an iodine atom transfer methodology provides a possible general method for the cylisation of ω-alkenyl α-nitroalkyl radicals.Cyclisation of intermediate α-nitroalkyl radicals, generated by photolysis of 1-(bicyclohept-5-en-endo-2-yl)-2-iodo-2-nitropropane 5a, gave a good yield of two diastereomeric tricyclic iodonitro compounds 6a and 7a.Photolysis of 1-(bicyclohept-5-en-endo-2-yl)-2-iodo-2-nitroethane 5b and 2-(but-3-enyl)-1-iodo-1-nitrocyclohexane 11 also gave the expected products from 5-exo cyclisation of the intermediate α-nitroalkyl radicals.The tricyclic iodonitro compound 6a was synthesised from the corresponding endo-methanesulfonate 15, the structure of which was determined by X-ray crystallography.
- Bowman, W. Russell,Brown, David S.,Burns, Catherine A.,Crosby, David
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p. 2083 - 2090
(2007/10/02)
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- Interesting Products Derived from the Reactions of 2,3-Diamino-2,3-dimethylbutane
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The diimine, N,N'-dibenzylidene-2,3-diamino-2,3-dimethylbutane (10), was successfully synthesized from 2,3-diamino-2,3-dimethylbutane (3) by reaction with excess benzaldehyde.The reaction of diimine 10 with permanganate/PTC at pH = 4.1 did not give corresponding dinitrone 11 but unexpectedly gave 3-benzoyl-4,4,5,5-tetramethyl-2-phenylimidazoline (13) in 45 percent yield.The imidazoline 13 was independently prepared by benzoylation of 4,4,5,5-tetramethyl-2-phenylimidazoline (9) which had been synthesized from diamine 3 and methyl benzimidate.The cyclic α-dinitrone,2,3-dihydro-2,2,3,3,5,6-hexamethylpyrazine 1,4-dioxide (4), synthesized from N,N'-dihydroxy-2,3-diamino-2,3-dimethylbutane (2) and 2,3-butanedione, underwent ozonolysis to yield the corresponding vicinal dinitro compound, 2,3-dimethyl-2,3-dinitrobutane (1), quantitatively.
- Gagnon, Janet L.,Walters, Thomas R.,Zajac, Walter W.,Buzby, John H.
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p. 6712 - 6715
(2007/10/02)
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- Viologen-mediated Reductive Desulfonylation of α-Nitro Sulfones by Sodium Dithionite
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Reductive desulfonylation of α-nitro sulfones to give the corresponding nitro compounds was carried out conveniently with sodium dithionite, by using octylviologen as an electron-transfer catalyst in organic solvent-water two-phase systems.Sulfones which do not have an α-nitro group are not desulfonylated.A reaction scheme involving a nitroalkyl radical has been proposed.
- Park, Kwanghee Koh,Lee, Chul Woo,Choi, Sook Young
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p. 601 - 604
(2007/10/02)
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- Addition Reactions of Cation Radicals of Nitroalkanes to Olefinic Compounds by the Use of Manganese(III) Pyridinecarboxylate
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Silyl derivatives of aci-nitroalkanes react with olefins such as silyl enol ether, vinyl sulfide, and enamine by oxidation with manganese(III) 2-pyridinecarboxylate to give the intermolecular addition products selectively.
- Narasaka, Koichi,Iwakura, Kazunori,Okauchi, Tatsuo
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p. 423 - 426
(2007/10/02)
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- Homolytic Alkylation of Enamines by Electrophilic Radicals
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The electrophilic radicals R* = p-O2NC6H4CH2* or Me2C(NO2)* add readily to CH2=C(NMe)2 to yield RCH2C(NMe2)2* which undergoes electron transfer with p-O2NC6H4CH2Cl or Me2C(NO2)2 to regenerate R*.Hydrolysis yields p-O2NC6H4CH2CONMe2 and Me2C=CHC(NMe2)2(1+), respectively. p-Nitrobenzyl radicals add readily to N-pyrrolidino- or N-morpholino-1-cycloalkenes to yield after hydrolysis the α-(p-nitrobenzyl)cycloalkanones.Photostimulated alkylation of N-pyrrolidino-1-cycloalkenes by Me2C(NO2)2 is not observed although in competitive reactions between the enamine and Me2C=NO2Li, the product from attack of Me2C(NO2)* upon the eneamine double bond is formed.The N-pyrrolidino-1-cycloalkenes are more reactive toward p-O2NC6H5CH2 than their morpholine analogues.
- Russell, Glen A.,Wang, Keyang
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p. 3475 - 3479
(2007/10/02)
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- Oxidative Cross-Coupling of Enolates with Nitronate Anions Promoted by Chloride Anions
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Nitronate anions derived from primary and secondary nitroalkanes undergo cross-coupling reactions with diethyl alkylmalonate anions in alcohol/DMF solution when treated with silver nitrate.A catalytic amount of chloride ions is necessary to promote selective reaction.
- Wrobel, Zbigniew,Makosza, Mieczyslaw
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p. 619 - 622
(2007/10/02)
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- Radical-Nucleophilic Substitution (SRN1) Reactions. Part 6. N-Anions of Diazoles in SRN1 and Oxidative Additions
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The anions of imidazole, benzimidazole, 5(6)-nitrobenzimidazole, and 5(and 6)-nitro-1H- and -2H-indazoles have been shown to undergo oxidative addition to the anion of 2-nitropropane (using potassium ferricyanide and sodium persulphate), and SRN1 reactions with Me2C(X)NO2 (X = Cl, Br, and NO2) to yield the corresponding 1-(1-methyl-1-nitroethyl) derivatives.The anions of 5(6)-nitrobenzimidazole and 5(6)-nitro-1H- and -2H-indazoles underwent reaction with p-nitrobenzyl chloride by a SRN1 and/or SN2 mechanism to yield the corresponding 1-(p-nitrobenzyl) derivatives.The ambident anions of 5- and 6-nitrobenzimidazole, 5-nitro-1H- and -2H-indazoles, and 6-nitro-1H- and -2H-indazoles gave ca. 50:50 mixtures of the N-1 alkylation products resulting from respective pairs of ambident anions.The 1-(1-methyl-1-nitroethyl) derivatives of benzimidazole and 5- and 6-nitro-1H-indazole underwent further substitution of the aliphatic nitro group with the respective diazole to yield 2,2-di(benzimidazol-1-yl)-, 2,2-dipropanes.
- Adebayo, Adelaide T. O. M.,Bowman, W. Russell,Salt, W. G.
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p. 1415 - 1421
(2007/10/02)
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- SUBSTITUENT EFFECT ON THE REACTION OF 2-(SUBSTITUTED PHENYL)-4,5-DIHYDRO-4,4,5,5-TETRAMETHYLIMIDAZOL-1-OXYL 3-OXIDES WITH NITRIC OXIDE: AN EXPERIMENTAL AND MNDO STUDY
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The relative rate constants of the oxygen transfer reaction of 2-(substituted phenyl)-4,5-dihydro-4,4,5,5-tetramethylimidazol-1-oxyl 3-oxides with nitric acid have been measured by using liquid chromatography (h.p.l.c.).The Hammett ρ value (-0.37) indicates that electron-donating substituents favour the reaction.This can be explained by a mechanism which includes electron transfer to nitric oxide and can be rationalised by frontier orbital energies and electron densities on the nitroxyl oxygen calculated by semiempirical MNDO methods.
- Shimomura, Osamu,Abe, Kazuhisa,Hirota, Minoru
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p. 795 - 798
(2007/10/02)
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- Pathways in the Reactions of Nitronate Ions with Sulphonyl Halides
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Primary and tertiary nitronate ions and sulphonyl bromides and iodides rapidly equilibrate with the nitrohalides and sulphinate ion.Products are determined by solvent and by the occurence of cross-equilibrum reactions, some of which have single-electron-transfer mechanism.The reaction of arene-sulphinate and thiolate ions with 1,2-dibromo-2-nitro-1-phenylethane gave E-β-nitrostyrene by Z-philic elimination in both cases, but the more basic thiolate ion also gave, by protophilic elimination, 2-bromo-2-nitro-1-phenylethene.
- Pigou, Paul E.,Stirling, Charles J. M.
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p. 725 - 730
(2007/10/02)
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- Radical-nucleophilic Substitution (SRN1) Reactions. Part 5. Anions of Nitroimidazoles in SRN1 and Oxidative Addition Reactions
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The anions of 2- and 4(5)-nitroimidazole, and 2-methyl-4(5)-nitroimidazole, have been shown to undergo SRN1 reactions with a range of halogeno-nitroalkanes (which include p-nitrobenzyl chloride, 2-bromo- and 2-chloro-2-nitropropane, 2,2-dinitropropane, 5-bromo-5-nitro-1,3-dioxane, and 2-(bromo- and chloromethyl)-1-methyl-5-nitroimidazole to yield the corresponding N(1)-(nitroalkyl) derivatives.The anions of 2-methyl-4(5)-nitro- and 4(5)-nitro-imidazole, but not the anion of 2-nitroimidazole, underwent oxidative addition to the anion of 2-nitropropane (using potassium ferricyanide and sodium persulphate as oxidants) to yield the corresponding N(1)-(1-methyl-1-nitroethyl) derivatives.The anions of 2-methyl-4-nitro- and 4-nitro-imidazole have also been shown to act as nucleofuges in the SRN1 reactions between their 1-(1-methyl-1-nitroethyl)-derivatives and anions (which include Me2CNO2- and PhSO2-).Steric constrains, kinetic control, and the nature of the intermediate radical anions in the above reactions are discussed.
- Adebayo, Adelaide T. O. M.,Bowman, W. Russell,Salt, W. G.
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p. 2819 - 2828
(2007/10/02)
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- THE CHEMISTRY OF DIACYL PEROXIDES - VIII. THE REACTIONS BETWEEN POLYFLUORODIACYL PEROXIDES AND 2-NITRO-2-NITROSOPROPANE--GENERATION OF BIS(POLYFLUOROALKYL) NITROXIDES
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Thermal decomposition of 2-nitro-2-nitrosopropane (4) in F113 (CCl2F-CClF2) solution involves C-NO bond fission and forms acetone as the major product.In the presence of polyfluorodiacyl peroxide (3), the oxidation of 4 by 3 to 2,2-dinitropropane (5) is the predominant reaction and bis(polyfluoroalkyl) nitroxide (1) is generated as one of the by-products.
- Zhao, Cheng-Xue,Chen, Guo-Fei,Jiang, Xi-Kui,Wang, Xian-Shan
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p. 597 - 606
(2007/10/02)
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- SUR LA REACTIVITE DE gem-BROMONITROALCANES EN PRESENCE DE THIOLATES.
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Reactions between various gem-bromonitro alcanes BrA1'-4 in the presence of t-C4H9S(1-) are shown to proceed at low temperature via either both radical coupling and SRN1 or radical coupling only and to lead efficiently to (A1'-4)2.
- Amrollah-Madjdabadi, Ali,Beugelmans, Rene,Lechevallier, Andre
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p. 4525 - 4528
(2007/10/02)
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- SRN1 AND OXIDATIVE ADDITION REACTIONS OF NITROIMIDAZOLE ANIONS
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The anions of 2- and 4(5)-nitroimidazoles react with aliphatic substituted nitro compounds and p-nitrobenzyl chloride by a SRN1 mechanism, or by oxidative addition to the anion of 2-nitropropane, to yield 1-alkyl-2-(or 4-)-nitroimidazoles.
- Adebayo, Adelaide T. O. M.,Bowman, Russell,Salt, W. G.
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p. 1943 - 1946
(2007/10/02)
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