- Preparation method of 2,5-dimethoxyphenylacetic acid
-
The invention belongs to the technical field of drug synthesis, and particularly relates to a preparation method of 2,5-dimethoxyphenylacetic acid, wherein the method comprises the following steps: A,reacting 1,4-dimethoxybenzene in a formylation system to obtain 2,5-dimethoxybenzaldehyde; B, reacting the 2,5-dimethoxybenzaldehyde obtained in the step A with a reducing agent, extracting a reaction system, then combining organic phases, drying, concentrating under reduced pressure and distilling a crude product to obtain 2,5-dimethoxybenzyl alcohol; C, reacting the 2,5-dimethoxybenzyl alcoholobtained in the step B with a bromination reagent to obtain 2-bromomethyl-1,4-dimethoxybenzene; and D, reacting the 2-bromomethyl-1,4-dimethoxybenzene obtained in the step C with magnesium or butyl lithium and carbon dioxide in a solvent to obtain the 2,5-dimethoxyphenylacetic acid. The yield and the total yield of the 2,5-dimethoxyphenylacetic acid obtained by the method disclosed by the invention are both higher than those of 2,5-dimethoxyphenylacetic acid synthesized by a Willegerdt-Kindler method.
- -
-
-
- Preparation method of 2,5-dimethoxyphenylacetic acid
-
The invention belongs to the technical field of drug synthesis, and particularly relates to a preparation method of 2,5-dimethoxyphenylacetic acid, wherein the preparation method comprises the following steps: A, reacting 1,4-dimethoxybenzene with formaldehyde under the action of hydrogen halide to obtain 2-halomethyl-1,4-dimethoxybenzene; B, reacting 2-halomethyl-1,4-dimethoxybenzene obtained inthe step A with a cyanation reagent, then diluting, washing, drying and concentrating under reduced pressure, and finally carrying out reduced pressure distillation to obtain 2(2,5-dimethoxyphenyl)acetonitrile; and C, hydrolyzing the 2(2,5-dimethoxyphenyl)acetonitrile obtained in the step B, cooling, extracting, merging, drying, concentrating under reduced pressure and purifying to finally obtainthe 2,5-dimethoxyphenylacetic acid. The yield and the total yield of the 2,5-dimethoxyphenylacetic acid obtained by the method disclosed by the invention are both higher than those of the 2,5-dimethoxyphenylacetic acid synthesized by a Willgerodt-Kindler method, and the yield and the total yield of the 2,5-dimethoxyphenylacetic acid are higher than those of 2,5-dimethoxyphenylacetic acid synthesized by the Willgerodt-Kindler method.
- -
-
Paragraph 0045-0048; 0053-0056; 0061-0064
(2021/02/06)
-
- Preparation method of 2, 5-dimethoxyphenylacetic acid
-
The invention belongs to the technical field of drug synthesis, and particularly relates to a preparation method of 2, 5-dimethoxyphenylacetic acid, which comprises the following steps: A. Reacting 1,4-dimethoxybenzene with formaldehyde under the action of hydrogen halide, extracting by the reaction system, merging with organic phases, drying, concentrating under reduced pressure, and purifying the crude product to obtain 2-halon methyl-1, 4-dimethoxybenzene ; and B, under the protection of inert gas, putting the 2-halo methyl-1, 4-dimethoxybenzene obtained in the step A, magnesium or butyl lithium and carbon dioxide into a solvent, and then carrying out extraction and deactivation, reduced pressure distillation, extraction, organic phase combination and reduced pressure concentration toobtain the 2, 5-dimethoxyphenylacetic acid. The yield and the total yield of the 2, 5-dimethoxyphenylacetic acid obtained by the method disclosed by the invention are both higher than those of the 2,5-dimethoxyphenylacetic acid synthesized by a Willgerodt-Kindler method.
- -
-
Paragraph 0041-0044; 0048; 0049; 0053; 0054; 0058; 0059
(2021/01/29)
-
- Discovery, synthesis and anti-atherosclerotic activities of a novel selective sphingomyelin synthase 2 inhibitor
-
The sphingomyelin synthase 2 (SMS2) is a potential target for pharmacological intervention in atherosclerosis. However, so far, few selective SMS2 inhibitors and their pharmacological activities were reported. In this study, a class of 2-benzyloxybenzamides were discovered as novel SMS2 inhibitors through scaffold hopping and structural optimization. Among them, Ly93 as one of the most potent inhibitors exhibited IC50 values of 91 nM and 133.9 μM against purified SMS2 and SMS1 respectively. The selectivity ratio of Ly93 was more than 1400-fold for purified SMS2 over SMS1. The in vitro studies indicated that Ly93 not only dose-dependently diminished apoB secretion from Huh7 cells, but also significantly reduced the SMS activity and increased cholesterol efflux from macrophages. Meanwhile, Ly93 inhibited the secretion of LPS-mediated pro-inflammatory cytokine and chemokine in macrophages. The pharmacokinetic profiles of Ly93 performed on C57BL/6J mice demonstrated that Ly93 was orally efficacious. As a potent selective SMS2 inhibitor, Ly93 significantly decreased the plasma SM levels of C57BL/6J mice. Furthermore, Ly93 was capable of dose-dependently attenuating the atherosclerotic lesions in the root and the entire aorta as well as macrophage content in lesions, in apolipoprotein E gene knockout mice treated with Ly93. In conclusion, we discovered a novel selective SMS2 inhibitor Ly93 and demonstrated its anti-atherosclerotic activities in vivo. The preliminary molecular mechanism-of-action studies revealed its function in lipid homeostasis and inflammation process, which indicated that the selective inhibition of SMS2 would be a promising treatment for atherosclerosis.
- Li, Yali,Huang, Taomin,Lou, Bin,Ye, Deyong,Qi, Xiangyu,Li, Xiaoxia,Hu, Shuang,Ding, Tingbo,Chen, Yan,Cao, Yang,Mo, Mingguang,Dong, Jibin,Wei, Min,Chu, Yong,Li, Huiti,Jiang, Xian-Cheng,Cheng, Nengneng,Zhou, Lu
-
p. 864 - 882
(2019/01/04)
-
- CD16A BINDING AGENTS AND USES THEREOF
-
Among other things, the present disclosure provides compounds, compositions thereof, and methods of using the same. In some embodiments, compounds of the present disclosure bind to Fc receptors, e.g., CD16a. In some embodiments, compounds of the present disclosure are useful for treating various conditions, disorders or diseases including cancer.
- -
-
-
- Promotion of Appel-type reactions by N-heterocyclic carbenes
-
N-Heterocyclic carbenes (NHCs) have been extensively used as a versatile class of catalysts and ligands in organocatalytic and organometallic chemistry. However, there are only a small number of synthetic applications where they act as reagents. Here we demonstrate that NHCs can be used as stoichiometric redox reagents for Appel-type halogenation reactions of alcohols. This new reactivity reveals a fresh and interesting aspect and enriches the chemistry of NHCs in an underexplored area. The potential of performing this chemical transformation at the catalytic level using an NHC-oxide derivative is also investigated.
- Hussein, Mohanad A.,Nguyen, Thanh Vinh
-
supporting information
p. 7962 - 7965
(2019/07/12)
-
- MLKL INHIBITORS
-
Purine derivatives that inhibit cellular necroptosis and/or human MLKL, pharmaceutical compositions thereof, and methods of treating an MLKL-mediated disorder with an effective amount of the compound or composition. Said MLKL-mediated disorder is pathology associated necroptosis, including ischemia-reperfusion damage, neurodegeneration, and inflammatory diseases such as acute pancreatitis, multiple sclerosis, inflammatory bowel disease, and allergic colitis.
- -
-
Paragraph 0709-0710
(2018/09/26)
-
- 3, 5-disubstituted hydantoin compound as well as preparation method and application thereof
-
The invention provides a 3, 5-disubstituted hydantoin compound as well as a preparation method and an application thereof. The structure of the compound is shown in formula I in the description. The application of the 3, 5-disubstituted hydantoin compound shown in the formula I or solvates, hydrates or salts of the compound in preparation of medicines for treating Alzheimer's disease, vascular dementia and other dementia diseases with memory impairment also belongs to the protection scope. Animal experiments prove that the compound has the effect of saving memory of animal models, has high safety, does not have mutagenicity, can stay in blood for several hours after oral administration and intravenous injection, and can enter the brain.
- -
-
Paragraph 0042; 0073; 0074; 0075; 0076
(2018/10/19)
-
- 1-Trifluoromethylisoquinolines from α-Benzylated Tosylmethyl Isocyanide Derivatives in a Modular Approach
-
The preparation of various 1-trifluoromethylisoquinolines from α-benzylated tosylmethyl isocyanide derivatives and the commercial Togni reagent using a radical cascade is reported. The starting isocyanides are readily prepared in a modular sequence from commercial tosylmethyl isocyanide via sequential double α-alkylation, and the radical reaction proceeds under mild conditions with high efficiency without any transition-metal catalyst via electron catalysis. This valuable protocol has been successfully applied to the total synthesis of CF3-mansouramycin B.
- Wang, Lin,Studer, Armido
-
p. 5701 - 5704
(2017/10/25)
-
- 4-oxo-alkylated tetramic acid compounds and preparation method thereof
-
The invention relates to novel compounds and a preparation method thereof. The general structural formula is shown as formula I in the description. Animal experiments prove that the compounds have the effect of saving memories of animal models, are high in safety, have no mutagenicity, can remain in blood for hours after oral administration and intravenous injection, can enter brains and can be used for preparing drugs for treating diseases such as Alzihemer's disease, Parkinson's disease, Huntington's disease, vascular dementia, schizophrenia, autism and the like.
- -
-
Paragraph 0079; 0080
(2017/12/09)
-
- 4-oxo-alkylated tetramic acid compound as well as preparation method and application thereof
-
The invention relates to a novel compound as well as preparation method and application thereof. The structural formula of the novel compound is as shown in a formula I. Animal tests show that the compound provided by the invention has a memory effect of rescuing animal models, is high in security and free of mutagenicity induction, can be retained for hours in blood after oral taking and intravenous injection, can be fed into brains and can be used for preparing medicines for treating senile dementia, Parkinsonism, Huntington diseases, vascular dementia, schizophrenia, autism and the like.
- -
-
Paragraph 0080; 0081
(2018/01/09)
-
- Approach to Merosesquiterpenes via Lewis Acid Catalyzed Nazarov-Type Cyclization: Total Synthesis of Akaol A
-
A Lewis acid catalyzed Nazarov-type cyclization of arylvinylcarbinol has been developed for the asymmetric synthesis of carbotetracyclic core of merosesquiterpenes. The reaction works only in the presence of 2 mol % of Sn(OTf)2 and Bi(OTf)3 in dichloroethane under elevated temperature. The methodology offers the synthesis of a variety of enantioenriched arylvinylcarbinols from commercially available (3aR)-sclareolide 9 in six steps with an eventual concise total synthesis of marine sesquiterpene quinol, akaol A (1a).
- Kakde, Badrinath N.,Kumar, Nivesh,Mondal, Pradip Kumar,Bisai, Alakesh
-
p. 1752 - 1755
(2016/05/19)
-
- Visible-Light-Induced Cyclization of Electron-Enriched Phenyl Benzyl Sulfides: Synthesis of Tetrahydrofurans and Tetrahydropyrans
-
A new approach to the preparation of tetrahydrofurans and tetrahydropyrans through a photoredox catalytic process is described. The introduction of a phenylsulfanyl auxiliary group permits the substrates to be readily oxidized to form cationic intermediates for sequential intramolecular cyclization. The method features mild reaction conditions and operational simplicity.
- Li, Wei,Yang, Chao,Gao, Guo-Lin,Xia, Wujiong
-
supporting information
p. 1391 - 1396
(2016/06/01)
-
- Self-assembled near-infrared dye nanoparticles as a selective protein sensor by activation of a dormant fluorophore
-
Design of selective sensors for a specific analyte in blood serum, which contains a large number of proteins, small molecules, and ions, is important in clinical diagnostics. While metal and polymeric nanoparticle conjugates have been used as sensors, small molecular assemblies have rarely been exploited for the selective sensing of a protein in blood serum. Herein we demonstrate how a nonspecific small molecular fluorescent dye can be empowered to form a selective protein sensor as illustrated with a thiol-sensitive near-IR squaraine ( Sq) dye (λabs= 670 nm, λem= 700 nm). The dye self-assembles to form non fluorescent nanoparticles (Dh = 200 nm) which selectively respond to human serum albumin (HSA) in the presence of other thiol-containing molecules and proteins by triggering a green fluorescence. This selective response of the dye nanoparticles allowed detection and quantification of HSA in blood serum with a sensitivity limit of 3 nM. Notably, the Sq dye in solution state is nonselective and responds to any thiol-containing proteins and small molecules. The sensing mechanism involves HSA specifi c controlled disassembly of the Sq nanoparticles to the molecular dye by a noncovalent binding process and its subsequent reaction with the thiol moiety of the protein, triggering the green emission of a dormant fluorophore present in the dye. This study demonstrates the power of a self-assembled small molecular fluorophore for protein sensing and is a simple chemical tool for the clinical diagnosis of blood serum.
- Anees, Palapuravan,Sreejith, Sivaramapanicker,Ajayaghosh, Ayyappanpillai
-
p. 13233 - 13239
(2015/03/30)
-
- Benzoquinones as inhibitors of botulinum neurotoxin serotype A
-
Although botulinum neurotoxin serotype A (BoNT/A) is known for its use in cosmetics, it causes a potentially fatal illness, botulism, and can be used as a bioterror weapon. Many compounds have been developed that inhibit the BoNTA zinc-metalloprotease lig
- Bremer, Paul T.,Hixon, Mark S.,Janda, Kim D.
-
p. 3971 - 3981
(2014/08/18)
-
- Multi-electron donor organic molecules containing hydroquinone methyl-ether as redox active units
-
Three hydroquinone dimethyl ether derivatives have been synthesized and characterized by X-ray diffraction. The electron donating properties were evaluated by using UV-vis spectroscopy, cyclic voltammetry and by ESR spectroscopy. The microcrystalline cation-radical salts of the three donor molecules were also isolated by using antimony pentachloride, a single electron Lewis acid oxidant.
- Khandelwal, Manish,Hwang, In-Chul,Nair, Prakash Chandran R.,Lee, Jung-Woo
-
p. 1190 - 1198
(2012/07/14)
-
- Synthesis and in vitro antibacterial activity of gemifloxacin derivatives containing a substituted benzyloxime moiety
-
A series of novel gemifloxacin (GMFX) derivatives containing a substituted benzyloxime moiety with remarkable improvement in lipophilicity were synthesized. The target compounds evaluated for their in vitro antibacterial activity against representative strains. Our results reveal that most of the target compounds have considerable potency against all of the tested Gram-positive strains including MRSA and MRSE (MIC: 90: 1 μg/mL) is 8-fold more active than GMFX, and 2-fold more active than GMFX and moxifloxacin against MRSE clinical isolates (MIC90: 4 μg/mL). Crown Copyright
- Feng, Lianshun,Lv, Kai,Liu, Mingliang,Wang, Shuo,Zhao, Jing,You, Xuefu,Li, Sujie,Cao, Jue,Guo, Huiyuan
-
p. 125 - 136
(2012/11/07)
-
- Synthesis and biological activity of pyridopyridazin-6-one p38α MAP kinase inhibitors. Part 2
-
This manuscript concludes the Structure Activity Relationship (SAR) on the pyridazinone scaffold and identifies a compound with subnanomolar p38α activity and 24 h coverage in the rat arthritis efficacy model.
- Tynebor, Robert M.,Chen, Meng-Hsin,Natarajan, Swaminathan R.,O'Neill, Edward A.,Thompson, James E.,Fitzgerald, Catherine E.,O'Keefe, Stephen J.,Doherty, James B.
-
p. 5971 - 5975
(2012/11/07)
-
- Diiron complexes with pendant phenol group(s) as mimics of the diiron subunit of [FeFe]-hydrogenase: Synthesis, characterisation, and electrochemical investigation
-
Four diiron hexacarbonyl complexes, [Fe2(μ-SCH 2-o-C6H4OMe)2(CO)6] (4a), [Fe2{μ-SCH2-o,m-C6H3(OMe) 2}2-(CO)6] (4b), [Fe2{μ-SCH 2-o,o′-C6H3(CO2Me)(OMe)} 2(CO)6] (4c) and the demethylated form of complex 4a, [Fe2(μ-SCH2-o-C6H4OH) 2(CO)6] (5a), were synthesised and fully characterised. Complexes 4b and 4c were also structurally analysed. Electrochemical investigations revealed that the integrity of the bridging linkages of the examined diiron complexes significantly affect their reduction reversibility and catalysis through a coupled chemical reaction in a unique ECE mechanism, widely adopted by complexes with the core {Fe2(CO)4-6}. Demethylation of complexes 4a and 1Me, [Fe2(μ-SCH 2)2CMe(CH2-o-C6H4OMe)(CO) 6], by BBr3 led to complexes (5a and 1H, [Fe 2(μ-SCH2)2CMe(CH2-o-C 6H4OH)-(CO)6]) with pendant phenol group(s), a weak acid. Deprotonation of the two complexes produced the pendant phenolate, which instantly intramolecularly substitutes the bound CO to yield species of the coordination form FeI-OR (R = phenolic moiety). Electrochemical investigation revealed that the pendant phenol groups in complexes 1H and 5a do not seem to improve their catalytic efficiency in proton reduction in the medium acetic acid/dichloromethane.
- Tang, Ying,Wei, Zhenhong,Zhong, Wei,Liu, Xiaoming
-
experimental part
p. 1112 - 1120
(2011/06/10)
-
- Preparation of pillar[n]arenes by cyclooligomerization of 2,5-dialkoxybenzyl alcohols or 2,5-dialkoxybenzyl bromides
-
The facile and efficient preparation of pillar[n]arenes (n = 5 or 6) was achieved by cyclooligomerization of 2,5-dialkoxybenzyl alcohols or 2,5-dialkoxybenzyl bromides with an appropriate Lewis acid catalyst at room temperature. The mechanism for this cyclooligomerization is presumed to be a Friedel-Crafts alkylation.
- Ma, Yingjie,Zhang, Zibin,Ji, Xiaofan,Han, Chengyou,He, Jiuming,Abliz, Zeper,Chen, Weixiang,Huang, Feihe
-
experimental part
p. 5331 - 5335
(2011/11/12)
-
- 2,5-Dihydroxybenzyl and (1,4-dihydroxy-2-naphthyl)methyl, novel reductively armed photocages for the hydroxyl moiety
-
(Chemical Equation Presented) Irradiation of alcohols, phenols, and carboxylic acids "caged" with the 2,5-dihydroxybenzyl group or its naphthalene analogue results in the efficient release of the substrate. The initial byproduct of the photoreaction, 4-hydroxyquinone-2-methide, undergoes rapid tautomerization into methyl p-quinone. The UV spectrum of the latter is different from that of the caging chromophore, thus permitting selective irradiation of the starting material in the presence of photochemical products. These photoremovable protecting groups can be armed in situ by the reduction of photochemically inert p-quinone precursors.
- Kostikov, Alexey P.,Popik, Vladimir V.
-
p. 9190 - 9194
(2008/03/14)
-
- Synthesis of N-(2,5-dimethoxybenzyl)-N-(5-fluoro-2-phenoxyphenyl)[carbonyl- 11C]acetamide ([carbonyl- 11C]DAA1106) and analogues using [11C]carbon monoxide and palladium(0) complex
-
N-(2,5-Dimethoxybenzyl)-N-(5-fluoro-2-phenoxyphenyl)acetomide (DAA1106), a potent and selective ligand for peripheral benzodiazepine receptor, and eight structurally related analogues were labelled with 11C at the carbonyl position using a low
- Rahman, Obaidur,Langstroem, Bengt
-
p. 1192 - 1199
(2008/04/05)
-
- CARBON-ISOTOPE MONOXIDE LABELING OF DAA1106 AND ITS ANALOGUES TO BE USED AS TRACERS FOR A PERIPHERAL TYPE BENZODIAZEPINE BINDING SITE
-
A potent and selective ligand for peripheral benzodiazepine receptor (PBR), N-(2,5-dimethoxybenzyl)-N-(5-fluoro-2-phenoxyphenyl)acetamide or DAA1106 and eight structurally related analogues were labelled with 11C at carbonyl position of the mol
- -
-
Page/Page column 43-44
(2010/11/26)
-
- 1-BENZYLINDOLE-2-CARBOXAMIDE DERIVATIVES
-
The present invention relates to i-benzylindole-2-carboxamide derivatives of formula I, or a pharmaceutically acceptable salt or solvate thereof. The invention also relates to pharmaceutical compositions comprising said 1-benzylindole-2-carboxamide deriva
- -
-
Page/Page column 16-17
(2010/11/24)
-
- Design, synthesis and biological evaluation of novel riccardiphenol analogs
-
A novel, facile, high yield, and less cumbersome synthesis of riccardiphenol analogs is described. The synthesized compounds were characterized and assessed for its in vitro activity in a panel of human cancer cell lines of differing origin: HuCCT-1, BxPC3, Panc-1, Mia-Paca, A431, Hep2, and HN006. HuCCT-1 was derived from an intrahepatic cholangiocarcinoma; BxPC3, Mia-Paca, and Panc-1 were derived from pancreatic cancers; A431 was derived from a vulvar epithelial carcinoma; and Hep2 and HN006 were derived from squamous cell carcinomas of the head and neck. The cytotoxicity of a newly developed riccardiphenol analog against human cancer cell lines was assessed. The cancer cells exhibited varying sensitivities to the compound, with IC50 values from 30 to 50 μM. This susceptibility was particularly interesting in the case of lines such as Hep2 and BxPC3 that are resistant to classic cytotoxic drugs as well as some targeted agents. These results demonstrate that the novel riccardiphenol analog has effective action against human-derived cancer cell in vitro.
- Kumar, Srinivas K.,Amador, Maria,Hidalgo, Manuel,Bhat, Sujata V.,Khan, Saeed R.
-
p. 2873 - 2880
(2007/10/03)
-
- 1,4-Benzoquinones with styryl substituents
-
2-Styryl-1,4-benzoquinone (1) and compounds 2 and 3 containing 1 as a substructure all proved to be highly reactive towards thermal or photochemical [4π + 2π] cyclodimerization reactions. Chemo-, regio- and stereoselective processes lead to dimers (compou
- Brehm, Isabella,Hinneschiedt, Sabine,Meier, Herbert
-
p. 3162 - 3170
(2007/10/03)
-
- Ultra-short acting neuromuscular blocking agents; di- and tri-substituted benzyl bisquaternary ammonium derivatives of bis(tropan-3α-ol)-diesters
-
Based on previous experiences with bisquaternary ammonium derivatives of bistropine esters of dicarboxylic acids we designed, synthesized and pharmacologically evaluated seventy dicarboxylic acid esters of tropine (tropan-3α-ol) bearing substituted N-benzyl quaternizing groups. Many of the quaternary derivatives of these bistropine diesters showed high neuromuscular blocking potency, very short onset and ultrashort or short duration of action in experimental animals.
- Gyermek, Laszlo,Lee, Chingmuh,Cho, Young-Moon,Nguyen, Nguyen,Tsai, Shen-Kou
-
p. 116 - 136
(2007/10/03)
-
- Synthesis and electrochemistry of platinum complexes of hydroquinon-2-ylmethyl- and p-benzoquinon-2-ylmethyldiphenylphosphine
-
Platinum(II) complexes of new (hydroquinon-2-ylmethyl)diphenylphosphine (PPh2thqH2) and diphenyl(quinon-2-ylmethyl)phosphine (PPh2tq) ligands have been studied. Reaction of (2,5-dimethoxybenzyl)diphenylphosphine (PPh2dmb) with [PtCl2(PhCN)2] afforded [PtCl2(PPh2dmb)2] 1a. Metathesis reactions gave the bromo (1b) and iodo (1c) congeners. Deprotection of the hydroquinone groups in 1a using boron tribromide followed by treatment with base produced the O,P-chelated hydroquinonate phosphine complex, cis-[Pt(O,P-PPh2thqH)2] 2. Reaction of 2 with hydrobromic acid afforded cis-[PtBr2(PPh2thqH)2] 3 which can be oxidised to give the quinone phosphine complex cis-[PtBr2(PPh2tq)2] 4. Unlike previously reported quinone phosphine complexes, 4 is robust and stable to hydrolysis; its reduction with excess of zinc and dilute hydrobromic acid produced cis-[Pt(O,P-PPh2thqH)2(ZnBr2)] 5. Crystal structure analyses of 2·2dmf, 4·0.5dcm and 5·2dmf were performed. The electrochemistries of 1b, 3, and 4 have been characterised by cyclic voltammetry and controlled potential electrolyses. Cyclic voltammograms of 4 in the presence of dilute hydrobromic acid exhibit a four-electron cathodic process, attributed to reduction to 3; those of 3 show an anodic process attributed to oxidation to 4. The electrochemistry of 4 under aprotic conditions is extraordinary. Although there are two well separated, pendant quinone substituents only a single one-electron reduction process is observed. The reduction affords a radical species (6?-) which has been characterised by cyclic voltammetry, and by EPR and UV/Vis/NIR spectroscopy. It is argued from the available data that 6?- is a novel platinum(IV) complex with bound hydroquinonate and semiquinonate (sq) groups, namely [PtBr2(O,P-PPh2thq)(O,P-PPh2tsq ?)]-, and a possible mechanism for its remarkable formation is discussed.
- Sembiring, Seri Bima,Colbran, Stephen B.,Craig, Donald C.
-
p. 1543 - 1554
(2007/10/03)
-
- Antineoplastic heteronapthoquinones
-
This invention relates to a naphthoquinone derivatives, to processes and to intermediates for preparing these derivatives, to pharmaceutical composition and to the use of these derivatives as antitumor agents in mammals.
- -
-
-
- Processes antineoplastic heteronaphthoquinones
-
This invention relates to a naphthoquinone derivatives, to processes and to intermediates for preparing these derivatives, to pharmaceutical composition and to the use of these derivatives as antitumor agents in mammals.
- -
-
-
- Enantiospecific total synthesis of (+)- and (-)-avarone and -avarol
-
Enantiopure avarol and its oxidized congener avarone are synthesized in both podal series from an optically pure Wieland-Miescher enone; preliminary results from biochemical studies are summarized.
- Locke, Edward P.,Hecht, Sidney M.
-
p. 2717 - 2718
(2007/10/03)
-
- In situ fourier transform infrared spectroscopy of molecular adsorbates at electrode-electrolyte interfaces: A comparison between internal and external reflection modes
-
The vibrational properties of 2,5-dihydroxybenzyl mercaptan (DHBM) irreversibly adsorbed on gold electrodes have been examined in situ in aqueous 0.1 M HC1O4 by two different Fourier transform infrared (FT-IR) spectroscopic techniques: (i) potential difference attenuated total reflection FT-IR (PD-ATR-FT-IR), using a thin layer of gold (~4 nm) sputtered on a (thick layer) Au-patterned ZnSe internal reflection element as the electrode and (ii) PD-FT-IR (external) reflection absorption spectroscopy (PD-FT-IRRAS) on a solid Au electrode. The results obtained with both techniques, using the spectrum of the monolayer in the reduced state as a reference, were found to be nearly identical, displaying a set of negative- and positive-pointing features. The first set matched, within experimental error, the most prominent peaks observed in the ATR-FT-IR spectra of the DHBM monolayer using either pure water or 0.1 M HC1O4 as a reference. Furthermore, the positive-pointing features in the PD-FT-IR spectra, which correspond to the product of the electrochemical oxidation of irreversibly adsorbed DHBM, were consistent with the presence of a quinone-type moiety, as would be expected on the basis of chemical considerations. These observations indicate that, to the level of sensitivity of these two methodologies, the mode of adsorption and reactivity of DHBM (and probably a number of other species as well) is not appreciably affected by possible differences in the metal surface microstructure.
- Bae,Sandifer,Lee,Tryk,Sukenik,Scherson
-
p. 4508 - 4513
(2007/10/02)
-
- Efficient pyrimidine dimer radical anion splitting in low polarity solvents
-
Photosensitized pyrimidine dimer splitting by a covalently linked methoxybenzene exhibited a strong solvent dependence. Fluorescence of the chromophore was quenched by the attached dimer, which was indicative of electron transfer from excited chromophore to dimer. The quantum efficiency of splitting of the dimer radical anion in the linked dimer?--chromophore?+ was calculated from the observed quantum yields of splitting and the degree of fluorescence quenching. The quantum efficiency of dimer radical anion splitting was remarkably dependent on solvent polarity, ranging from 0.05 in water to ~0.5 in low polarity solvent mixtures (e.g., heptane/1,4-dioxane, 95:5). The results were rationalized in terms of competition of splitting and back electron transfer within the charge-separated species. The latter pathway may be slowed due to its exergonicity in low polarity media, in accord with Marcus inverted behavior. Photolyases may be effective for splitting dimers by providing catalytic groups and a medium in which both dimer radical anion formation and splitting are efficient.
- Hartzfeld, Donna G.,Rose, Seth D.
-
p. 850 - 854
(2007/10/02)
-
- The Synthesis of Bisanthraquinones Joined by Polyether Linkages
-
Derivatives of quinizarin linked by polyether chains have been prepared by the annelation of bis(quinone monoacetals) with the anions of substituted 3-cyanophthalides.
- Russell, Richard A.,Longmore, Robert W.
-
p. 1479 - 1486
(2007/10/02)
-
- Polymeric dihydroxy compounds and their use as stabilizers for polymers
-
Polymer dihydroxy compounds corresponding to the following formula STR1 in which a process for their production and their use in thermoplastic molding compositions.
- -
-
-
- A CONVENIENT APPROACH TO THE TOTAL SYNTHESIS OF (+/-) 4-DEMETHOXYDAUNOMYCINONE
-
A convenient and most practical approach to the synthesis of (+/-) 4-demethoxydaunomycinone starting from 2-methylhydroquinone is described.
- Rao, A. V. Rama,Chanda, Bhanu,Borate, H. B.
-
p. 3555 - 3561
(2007/10/02)
-