- Completely regioselective, highly stereoselective syntheses of cis-Bisfullerene[60] adducts of 6,13-disubstituted pentacenes
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(Matrix Presented) cis-Bisfullerene[60] adducts of 6,13-disubstituted pentacenes (R = Ph, 4′-hydroxymethylphenyl) are synthesized in 75percent to 85percent isolated yields under kinetically controlled Diels-Alder conditions. The cycloadditions are completely regioselective and highly stereoselective, with only traces of the diastereomeric trans-bisfullerene[60] adducts forming.
- Miller, Glen P.,Mack, James
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Read Online
- Synthesis and electrochemical characterization of a new benzodioxocine-fused poly(: N -methylpyrrole) derivative: A joint experimental and DFT study
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In this study, our findings from experimental studies were presented on the synthesis of a new electropolymerizable monomer, 2-methyl-5,10-dihydro-2H-benzo[6,7][1,4]dioxocino[2,3-c]pyrrole (XyPMe), regarding the cyclization reaction of diethyl N-methyl-3,4-dihydroxypyrrole-2,5-dicarboxylate and 1,2-bis(bromomethyl)benzene with concomitant hydrolysis and decarboxylation reactions. The critical step in this synthetic pathway was to determine the optimal temperature of decarboxylation utilizing TGA analysis, which decreases in situ polymerization side-product formation significantly. Following the preparation of the target monomer, the electropolymerization reaction was then conducted, and the optoelectronic properties were investigated in detail. In order to better illuminate the effects of N-alkylation and the heterocyclic ring system on the polymer backbones, we have included and theoretically studied the electronic properties of two monomers already synthesized in our laboratory, possessing the butyl group on the pyrrole ring (XyPBu) and the thiophene scaffold on its structure (XyT), and their corresponding oligomers (n = 2 to 11, n indicates the consecutive unit number). This combined experimental and theoretical research provides a pathway for advanced conjugated systems with predictable electronic and structural properties to be established.
- Kurtay, Gülbin,Soganci, Tugba,Sarikavak, Kübra,Ak, Metin,Güllü, Mustafa
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Read Online
- Synthesis and computational bandgap engineering of New 3,4-Alkylenedioxypyrrole (ADOP) derivatives and investigation of their electrochromic properties
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This research highlights the degree of conformity between our electrochemical and theoretical studies conducted on the newly designed electropolymerizable monomers (BuDOP, BenDOP and BenzoDOP) possessing 3,4-alkylenedioxypyrrole (ADOP) backbone (BuDOP). We tried to select logical enhancing of the structures in a stepwise in order to discuss the effects of benzene (BenDOP) and benzodioxane (BenzoDOP) like aromatic subunits to the electrochromic properties of the target monomers. Following to the completion of the synthetic steps, appropriate structural analyses of monomers were performed (FT-IR, GC-MS, 1H-NMR, 13CNMR). Subsequently, their corresponding polymers were prepared by electrochemical oxidation and characterized. Afterwards, our consecutive efforts have been contributed to theoretical studies in order to obtain information about their structural properties. To this aim, geometry optimizations were carried out using hybrid density functional theory (DFT/B3LYP/LANL2DZ) and HOMO, LUMO energy levels, HOMO-LUMO energy gaps (AE), electron affinity (EA) as well as ionization potential (IP) values were calculated. Theoretical data were then used for identifying the structure-electronic properties relationship and we aimed to determine the electrochromic properties of the studied monomers. Our results from the B3LYP/LANL2DZ calculations indicated that P(BenDOP) has the lowest HOMO-LUMO gap and we predicted that theoretical data were in good agreement with the experimental studies.
- Kurtay, Gulbin,Soganci, Tugba,Ak, Metin,Gullu, Mustafa
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Read Online
- Structure-Activity Relationships of Benzamides and Isoindolines Designed as SARS-CoV Protease Inhibitors Effective against SARS-CoV-2
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Inhibition of coronavirus (CoV)-encoded papain-like cysteine proteases (PLpro) represents an attractive strategy to treat infections by these important human pathogens. Herein we report on structure-activity relationships (SAR) of the noncovalent active-site directed inhibitor (R)-5-amino-2-methyl-N-(1-(naphthalen-1-yl)ethyl) benzamide (2 b), which is known to bind into the S3 and S4 pockets of the SARS-CoV PLpro. Moreover, we report the discovery of isoindolines as a new class of potent PLpro inhibitors. The studies also provide a deeper understanding of the binding modes of this inhibitor class. Importantly, the inhibitors were also confirmed to inhibit SARS-CoV-2 replication in cell culture suggesting that, due to the high structural similarities of the target proteases, inhibitors identified against SARS-CoV PLpro are valuable starting points for the development of new pan-coronaviral inhibitors.
- Welker, Armin,Kersten, Christian,Müller, Christin,Madhugiri, Ramakanth,Zimmer, Collin,Müller, Patrick,Zimmermann, Robert,Hammerschmidt, Stefan,Maus, Hannah,Ziebuhr, John,Sotriffer, Christoph,Schirmeister, Tanja
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supporting information
p. 340 - 354
(2020/10/19)
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- Novel bridged tetradentate fourth subgroup metal complex as well as preparation method and application thereof (by machine translation)
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The invention provides a novel bridged tetradentate fourth subgroup metal complex and a preparation method and application thereof, wherein the complex has a formula a structure, the temperature tolerance is good, and the complex can maintain very high catalytic activity under 120 °C, can obtain ultrahigh molecular weight polyethylene, and can catalyze ethylene and norbornene, 1 - hexene and 1 - octene copolymerization reaction to obtain a polymer product with high comonomer insertion rate. (by machine translation)
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Paragraph 0223-0226; 0228; 0229-0231
(2020/10/14)
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- Formal [5+1] annulation reactions of dielectrophilic peroxides: Facile access to functionalized dihydropyrans
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A general [5+1] annulation reaction, which utilized 4-bromo- or 4-mesyloxy-but-2-enyl peroxides as unique five-atom bielectrophilic synthons to participate in the C-C and the subsequent umpolung C-O bond-forming reactions with C1 nucleophiles, has been developed for the facile synthesis of 2,2-disubstituted dihydropyrans in high yields under mild basic conditions. The dihydropyrans, which are readily prepared on a gram scale by this new method, can be flexibly transformed into the biologically important tetrahydropyrans and pyranones in 1-2 steps.
- Zhong, Chen,Yin, Qi,Zhao, Yukun,Li, Qinfeng,Hu, Lin
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p. 13189 - 13192
(2020/11/09)
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- THIENODIAZEPINE DERIVATIVES AND APPLICATION THEREOF
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The present invention relates to a class of thienodiazepine derivatives and an application thereof in the preparation of a drug for the treatment of diseases associated with bromodomain and extra-terminal (BET) Bromodomain inhibitors. Specifically, the present invention relates to compounds represented by formulas (I) and (II), as well as pharmaceutically acceptable salts thereof.
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Paragraph 0151-0153; 0253-0255
(2020/08/09)
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- 2,3-Dihalo- and 2,3,6,7-Tetrahaloanthracenes by Vollhardt Trimerization
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We efficiently synthesized otherwise difficult to obtain 2,3- and 2,3,6,7-halogenated anthracenes with diverse east/west substituents. Key steps involve the (i) Vollhardt cyclization of bis(propargyl)benzenes with bis(trimethylsilyl)acetylene, (ii) halo-desilylation introducing chlorine, bromine, or iodine substituents, and (iii) dehydrogenation. Pd catalysis allows selective functionalization at the anthracenes' east/west positions. A tetrahydropentacene is synthesized and derivatized via the same strategy, employing tetrapropargylbenzene.
- Hoffmann, Hendrik,Mukanov, Diana,Ganschow, Michael,Rominger, Frank,Freudenberg, Jan,Bunz, Uwe H. F.
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p. 9826 - 9834
(2019/08/20)
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- Reducing Diastereomorphous Bis(phosphane oxide) Atropisomers to One Atropisomerically Pure Diphosphane: A New Ligand and a Novel Ligand-Preparation Design
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1,1′-Biphenyl-2,2′-diphosphanes with an achiral bridge spanning C-5 and C-5′ form atropisomers that are enantiomers. Accessing them in an atropisomerically pure form requires resolving a racemic mixture thereof or of a bis(phosphane oxide) precursor. 1,1′-Biphenyl-2,2′-diphosphanes with a homochiral bridge spanning C-5 and C-5′ form atropisomers that are diastereomers. We synthesized the first compound of this kind 1) atropselectively and 2) under thermodynamic control—seemingly a first-time exploit in diphosphane synthesis. The selectivity-inducing step was a high-temperature reduction of two non-interconverting bis(phosphane oxide) atropisomers (60:40 mixture). It furnished the desired diphosphane atropisomerically pure (and atropconvergently because the yield was 67 %). This diphosphane proved worthwhile in Tsuji–Trost allylations, the Hayashi addition of phenylboronic acid to cyclohexenone, and the asymmetric hydrogenation of methyl acetoacetate (up to 95 % yield and 95 % ee).
- Sartorius, Frank,Trebing, Marc,Brückner, Charlotte,Brückner, Reinhard
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supporting information
p. 17463 - 17468
(2017/11/27)
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- Improved Halogenation of Methyl Aromatics and Methyl Heteroaromatics: Unexpected Reactivity of Tetrahalogeno-diphenylglycolurils
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1,3,4,6-Tetrachloro (TCDGU) and 1,3,4,6-tetrabromo-3α,6α-diphenylglycolurils smooth halogen oxidizers have been exploited in a new direction as reagents for free radical substitution toward some N-halosuccinimide nonreactive bis-heterocycles. An unexpected selectivity and reactivity were observed with methyl benzenes, methyl heterocycles, and methyl-bis-heterocycles of interest. A chemometric study has been performed to optimize five independent factors of the chlorination reaction with TCDGU. The predictive model was established either for the halogenation conversion and the ratio of monochlorination.
- Moretti, Florian,Poisson, Guillaume,Marsura, Alain
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p. 173 - 183
(2016/05/19)
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- Synthesis and Crystal Structure of a Novel Glycoluril Molecular Scaffold
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Abstract: A novel glycoluril scaffold 1, namely 1,6-(1,2-xylylene)-3,4-(1,3-dimetheneyl-hexahydropyrimidine)tetrahydroimidazo[4,5-d]imidazole-2,5(1H,3H)-dione, was synthesized by the Mannich reaction of 1,6-(1,2-xylylene)tetrahydroimidazo[4,5-d]imidazole-2,5(1H,3H)-dione 5 with propanediamine and paraformaldehyde. The yielded product 1 was confirmed with IR, NMR, EI-MS. X-ray crystallographic technique was also conducted and the result showed the crystal belongs to monoclinic system, space group P21/c with unit cell parameters a?=?10.6892(11)??, b?=?12.1226(9)??, c?=?13.7822(13)??, α?=?90°, β?=?112.620(4)°,γ?=?90°, V?=?1648.5(3)??3, Z?=?4, Dc?=?1.428, Mr?=?354.41, μ?=?0.098?mm?1, F(000)?=?752, R1?=?0.0522 and wR2?=?0.1138. Graphical Abstract: A novel molecular scaffold, containing a heterocyclic ring instead of an aromatic ring, was synthesized by the Mannich reaction based on glycoluril.[Figure not available: see fulltext.]
- Wang, Zhi-guo,Yu, Wei,Zheng, He-qi,Wang, Zhi-gang
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p. 208 - 212
(2016/05/02)
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- Triphenylphosphine-N-bromosuccinimide mediated chemoselective cyclodehydration of diols
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A triphenylphosphine-N-bromosuccinimide mediated chemoselective cyclodehydration of diols is presented for the synthesis of polysubstituted tetrahydrofurans. 1,4-Diols and their derivatives can be rapidly cyclized to furnish tetrahydrofurans in high yields with one equivalent of Ph3P/NBS. Higher amount of Ph3P/NBS leads to the formation of dibromobutanes.
- Zhao, Shuo,Wu, You,Sun, Qi,Cheng, Tie-Ming,Li, Run-Tao
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p. 1154 - 1162
(2015/04/14)
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- Preparation of an EDOT-based polymer: Optoelectronic properties and electrochromic device application
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Here we present the synthesis, characterization and electropolymerization of a new EDOT-based monomer; 5,10-dihydrobenzo[f]thieno[3,4-b][1,4]dioxocine (DTD). Electrochemical polymerization of DTD was performed potentiostatically by using dichloromethane (DCM) as solvent and tetrabutylammonium hexafluorophosphate (TBPF6) as supporting electrolyte. Homopolymer [P(DTD)] films and copolymer [P(DTD-co-TPA)] films of DTD prepared by using 4-(2,5-di(thiophen-2-yl)-1H-pyrrole-1-yl)butane-1-amine (TPA) were characterized via CV and UV-vis spectroscopy. Spectroelectrochemical analysis of P(DTD) revealed electronic transitions at 585 nm (π-π transition) with an electronic band gap of 1.69 eV. Electrochromic studies revealed that P(DTD) has competitive properties to EDOT. Furthermore, a dual-type complementary colored polymer electrochromic device based on P(DTD) and P(TPA) was constructed in sandwich configuration. Spectroelectrochemical studies revealed that the oxidized state of the device shows a blue color whereas it is yellow in the reduced state. The maximum contrast (Δ%T) and switching time of the device were measured as 25.5% and 0.5 s for 385 nm and 21% and 1.0 s for 550 nm.
- Soganci, Tugba,Kurtay, Gülbin,Ak, Metin,Güllü, Mustafa
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p. 2630 - 2639
(2015/02/05)
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- Benzosulfones as photochemically activated sulfur dioxide (SO2) donors
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Sulfur dioxide (SO2) is a gaseous environmental pollutant which is routinely used in industry as a preservative and antimicrobial. Recent data suggests that SO2 may have value as a therapeutic agent. However, due to its gaseous nature, localizing SO2 generation is challenging. Herein, various 1,3-dihydrobenzo[c]thiophene 2,2-dioxides (benzosulfones) were prepared as candidates for photochemically activated sulfur dioxide (SO2) generation. These compounds were found to be stable in buffer but were photolysed upon irradiation with UV light to generate SO2. Our data indicates that photolysis of benzosulfones depends on substituents, and that the presence of electron donating groups results in an enhanced yield of SO2. This journal is
- Malwal, Satish R.,Chakrapani, Harinath
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p. 2399 - 2406
(2015/03/04)
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- Design and synthesis of amide derivatives as S-adenosyl-L-homocysteine hydrolase inhibitors
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In this study, a series of amide derivatives were synthesized and evaluated for their S-adenosyl-Lhomocysteine hydrolase (SAHase) inhibitory activities. The results demonstrated that most of compounds displayed potent SAHase inhibitory activities. Interestingly, compounds 11 and 14 exhibited more potent inhibitory effects than the aristeromycin, one of the most potent SAHase inhibitors known so far. Compounds 12, 13, 15 and 17 exhibited a moderate effect (IC5010.0 μM). The structure-activity relationship found that compounds with substituted indazole-5-yl group at Ar position and ethylamino group at the side chain showed better SAHase inhibitory activities.
- Tan, Xiangduan,Wang, Panfeng,Nian, Siyun,Wang, Guoping
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p. 112 - 117
(2014/01/23)
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- Generation of (nonafluoro-tert-butoxy)methyl ponytails for enhanced fluorous partition of aromatics and heterocycles
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The reaction of sodium perfluoro-tert-butoxide with benzylic carbon-bromide bond(s) leads to the formation of (nonafluoro-tert-butoxy)methyl ponytail(s), which can enhance the fluorous solubility and partition of aromatics and heterocycles.
- Zhao, Xi,Ng, Wing Yan,Lau, Kai-Chung,Collis, Alana E. C.,Horvath, Istvan T.
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experimental part
p. 3909 - 3914
(2012/06/30)
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- N-Halosuccinimide/SiCl4 as general, mild and efficient systems for the α-monohalogenation of carbonyl compounds and for benzylic halogenation
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Combinations of N-halosuccinimide and tetrachlorosilane in acetonitrile were found to be efficient systems for the selective α-monohalogenation of carbonyl compounds as well as for benzylic halogenation under mild conditions.
- Salama, Tarek A.,Novák, Zoltán
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experimental part
p. 4026 - 4029
(2011/08/09)
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- PHENYLENE OXO-DIESTER PLASTICIZERS AND METHODS OF MAKING
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A process for making non-phthalate, 1,2-phenylene oxo-diester plasticizers for polymer compositions, by selectively hydrogenating naphthalene to form a partially hydrogenated naphthalene, oxygenating said partially hydrogenated naphthalene to form phenylene diacids, and esterifying said phenylene diacids with oxo-alcohols to form 1,2-phenylene oxo-diesters. Also a process for making phenylene oxo-diester plasticizers by selectively brominating xylenes to form bisbromomethylbenzene, catalytic carboalkoxylation of the bromo-compound to form phenylene diacetate, followed by transesterification to form the phenylene oxo-diester.
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Page/Page column 13; 19
(2011/04/25)
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- AMINOBENZOCYCLOHEPTENE DERIVATIVES, METHODS FOR PREPARING THE SAME AND USES THEREOF IN THERAPY
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A compound of the general formula (I) as an active principle for treating cancer, specifically tumors, in particular diseases involving inhibition of metalloproteases, such as Aminopeptidase-N. Pharmaceutical compositions comprising the compound of general formula (I). Methods of treatment using the compound of general formula (I).
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Page/Page column 4
(2010/04/23)
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- Poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide), N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide and novel poly(N,N′-dibromo-N-phenylbenzene-1,3-disulfonamide) as powerful reagents for benzylic bromination
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N,N,N′,N′-Tetrabromobenzene-1,3-disulfonamide [TBBDA], poly(N,N′-dibromo-N-ethyl-benzene-1,3-disulfonamide) [PBBS], and novel poly(N,N′-dibromo-N-phenylbenzene-1,3-disulfonamide) [PBPS] can be used for bromination of benzylic positions in solvent.
- Ghorbani-Vaghei, Ramin,Chegini, Mohammad,Veisi, Hojat,Karimi-Tabar, Mehdi
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scheme or table
p. 1861 - 1865
(2009/07/19)
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- Benzylic brominations with N-bromosuccinimide in (Trifluoromethyl)benzene
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A variety of benzylic brominations were performed by using N-bromosuccinimide in (trifluoromethyl)benzene with photochemical activation in the presence of 2,2′-azobisisobutyronitrile, 1,1′- azobis(cyclohexanecarbonitrile), or benzoyl peroxide as the radical initiator. This system provides clean, rapid, and high-yielding reactions with replacement of conventional solvents, such as tetrachloromethane, by less-toxic (trifluoromethyl)benzene. Georg Thieme Verlag Stuttgart.
- Suarez, Diana,Laval, Gilles,Tu, Shang-Min,Jiang, Dong,Robinson, Claire L.,Scott, Richard,Golding, Bernard T.
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experimental part
p. 1807 - 1810
(2010/02/28)
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- Visible-light-promoted Wohl-Ziegler functionalization of organic molecules with N-bromosuccinimide under solvent-free reaction conditions
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The visible-light-induced transformation of toluenes with N-bromosuccinimide (NBS) under solvent-free reaction conditions (SFRC) was studied. The reaction took place in spite of the very restricted molecular motion; toluenes could be regioselectively converted to benzyl bromides. Selective radical-chain reactions with NBS were carried out in liquid/liquid and in solid/solid systems; furthermore, reactions could be performed in the presence of air. The radical scavenger TEMPO (=2,2,6,6-tetramethylpiperidin-1- yloxy) completely suppressed the side-chain bromination of toluenes with NBS under SFRC. Electron-withdrawing groups decreased the reactivity of the toluenes, and the Hammett reaction constant ρ+ = -1.7 indicated involvement of polar radical intermediates with electrophilic character.
- Jereb, Marjan,Zupan, Marko,Stavber, Stojan
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experimental part
p. 555 - 566
(2009/09/06)
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- Secondary interactions in bromomethyl-substituted benzenes: Crystal structures of three α,α′-bis-bromoxylenes, 1,2,3,5-tetrakis(bromomethyl)benzene, and 1,2,4,5-tetrakis(bromomethyl)benzene
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X-Ray structure determinations of all three isomers of bis(bromomethyl) benzene and of two isomeric tetrakis(bromomethyl)benzenes show that the packing of the molecules is determined principally by interactions of the bromomethyl groups (C-H ? Br and Br ? Br), except for ortho-bis (bromomethyl)benzene, in which C-H ? π interactions play a major role.
- Jones, Peter G.,Ku?, Piotr
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p. 725 - 731
(2008/10/09)
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- Free radical bromination by the H2O2-HBr system on water
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An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 40 W incandescent light bulb serves as a source of bromine radicals. Various substituted toluenes (H, Me, tBu, Br, COOEt, COPh, NO2) were brominated at the benzyl position. This haloperoxidase-like system for benzylic bromination does not require the presence of metal ions or an organic solvent for efficient conversion of methyl-arenes to benzyl bromides.
- Podgor?ek, Ajda,Stavber, Stojan,Zupan, Marko,Iskra, Jernej
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p. 7245 - 7247
(2007/10/03)
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- Rational Design and Synthesis of Novel Dimeric Diketoacid-Containing Inhibitors of HIV-1 Integrase: Implication for Binding to Two Metal Ions on the Active Site of Integrase
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Discovery of diketoacid-containing compounds as HIV-1 integrase (IN) inhibitors played a major role in validating this enzyme as an important target for the development of therapeutics against HIV infection. In fact, S-1360, the first clinically used IN inhibitor containing a triazole ring as a bioisostere of a carboxylic acid moiety belongs to this class of compounds. To understand the role of divalent metal-chelating in the inhibition of IN (J. Med. Chem. 2002, 45, 5661-5670), we designed and synthesized a series of novel dimeric diketo-containing compounds with the notion that such dimeric compounds may simultaneously bind to two divalent metal ions on the active site of IN. We rationalized that the two diketo subunits separated by uniquely designed linkers can potentially chelate two metal ions that are either provided from one IN active site or two active sites juxtaposed together in a higher order tetramer. Herein, we show that all the new compounds are highly potent against purified IN with varied selectivity for strand transfer, and that some of the analogues exert potent inhibition of the cytopathic effect of HIV-1 in infected CEM cells. This study represents the first attempt to rationally target two divalent metal ions on the active site of IN and may have potential implications for the design of second generation diketoacid-containing class of inhibitors.
- Long, Ya-Qiu,Jiang, Xiao-Hua,Dayam, Raveendra,Sanchez, Tino,Shoemaker, Robert,Sei, Shizuko,Neamati, Nouri
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p. 2561 - 2573
(2007/10/03)
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- Side chain bromination of mono and dimethyl heteroaromatic and aromatic compounds by solid phase N-bromosuccinimide reaction without radical initiator under microwave
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A series of side chain mono and dibromo derivatives of mono and dimethyl heteroaromatic and aromatic compounds (1-17) were synthesized by one step solid phase N-bromosuccinimide (NBS) reaction without radical initiator by microwave irradiation. The benzylic mono and dibromo products were exclusively preferred except in the case of 6-methylpyridine amides (8 and 9) where nuclear and also side chain bromination resulted. Naphthyridine systems resulted improved yields. By this method, we also report the synthesis of 2-pivaloylaminopterin-6- carbaldehyde.
- Goswami, Shyamaprosad,Dey, Swapan,Jana, Subrata,Adak, Avijit Kumar
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p. 916 - 917
(2007/10/03)
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- A simple and efficient iodination of alcohols on polymer-supported triphenylphosphine
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A simple, mild, and high-yielding procedure for the iodination of allylic, benzylic, and other primary alcohols using a combination of iodine and imidazole on polymer-supported triphenyl phosphine is described.
- Anilkumar, Gopinathan,Nambu, Hisanori,Kita, Yasuyuki
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p. 190 - 191
(2013/09/06)
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- New synthetic route to [bis-1,2-(aminomethyl)benzene]dichloroplatinum(II) complexes, screening for cytotoxic activity in cisplatin-sensitive and resistant human cancer cell lines, and reaction with glutathione
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A new synthetic route to [bis-1,2-(aminomethyl)benzene]dichloroplatinum(II) complexes is described. o-Xylene and the 4-methoxy substituted derivative were used as starting points for the synthesis: benzylic bromination with N-bromosuccinamide /benzoylperoxide followed by the substitution of the benzyl bromides for azide and finally a catalytic hydrogenation with Pd/C of the diazides gave the desired diamines ligands. An attempt to synthesize the 4,6-dimethoxy derivative was unsuccessful due to the bromination of the aromatic ring. The diamines were complexed with K2PtCl4 to give the target Pt(II) complexes: [1,2-bis(aminomethyl)benzene]dichloroplatinum(II) (4a) and [1,2-bis(aminomethyl)-4-methoxy-benzene]dichloroplatinum(II) (4b). Screening for cytotoxic activity was done in comparison to cisplatin in a panel of eight human cancer cell lines; in all cases, the 4-methoxy derivative 4b was less active than the unsubstituted analog, 4a. In four cell lines 4a was as potent as cisplatin, while in the other four lines cisplatin was considerably more potent then 4a. The 5637 bladder cancer cell line was made 4-5 fold resistant to either cisplatin or [d,l-trans-1,2-diaminocyclohexane]dichloroplatinum(II); 4a showed some cross resistance (2-3 fold) to both resistant cell lines. The reactivity of 4a towards substitutions with glutathione (GSH), a biological thiol involved in intrinsic and acquired resistance to Pt-complexes, was measured by a RP-HPLC method. It was found that the second-order rate constant for the reaction of 4a with GSH was similar to that that reported for CDDP, indicating that reactivity towards GSH does not explain the different levels of cross resistance.
- Rinke,Gruenert,Bednarski
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p. 763 - 769
(2007/10/03)
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- Catalytic intramolecular addition of metal carbenes to remote furans
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(formula presented) Diazo esters and diazo ketones linked to a furan undergo catalytic intramolecular addition of an intermediate metal carbene to the remote furan to form diendiones with ring sizes up to 17. Regioselectivity is catalyst dependent with addition to either the more or less substituted double bond. The high product yields and absence of need for high dilution suggest that this methodology is general for macrocycle preparations.
- Doyle, Michael P.,Chapman, Brant J.,Hu, Wenhao,Peterson, Chad S.,McKervey, M. Anthony,Garcia, Concepcion F.
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p. 1327 - 1329
(2008/02/09)
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- A new synthesis and application of N, N'-dibromo-N, N'-1,2-ethylene bis(2,5-dimethyl benzene sulfonamide); as a novel selective bromination agent for aromatic compounds
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Reaction Between Novel Compound; N, N' dibromo-N, N'-1,2- ethylene bis(2,5- dimethyl benzene sulfonamide) and aromatic compounds in the carbontetrachloride produces bromo aromatic compounds. In the case of benzene rings that contain mono activated substituted, only para - bromo isomer was formed. At the presence of benzoyl peroxide in the reaction mixture α - Hydrogen from alkyl side chain was substituted with bromine.
- Ardeshir, Khazaei,Abbas, Shirdarreh
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p. 4079 - 4085
(2007/10/03)
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- Photolysis of a series of α-brominated ortho-xylenes in apolar solvents
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The α-brominated ortho-xylenes have been subjected to 254 nm irradiation in deaerated benzene, isooctane and benzene-cyclohexene.The product analysis revealed that homolysis of the C-Br bond is followed by a series of hydrogen abstraction and radical recombination reactions resulting in xylenes more and less brominated than the starting compound.The less brominated products are formed with higher quantum yield when cyclohexene is present, due to hydrogen abstraction by the o-benzyl radical formed initially, together with cyclohexene dimers.Additionally, the formation of 2-bromo-2,4,4-trimethylpentane is observed when isooctane is the solvent.The quantum yields observed for the photolysis of 1 and 2 are higher in benzene than in isooctane, suggesting sensitization by benzene.A biradical intermediate of the type o-quinodimethane was expected in the case of (a) photolysis of the o-benzyl radical formed (biphotonic process) or (b) intramolecular hydrogen abstraction.However, the addition of cyclohexene failed to produce the expected Diels-Alder adduct.The synthesis of the novel α,α-dibromo-o-xylene 3 is reported.
- Rezende, Daisy de B.,Campos, Ivan P. de Arruda,Toscano, Vicente G.,Catalani, Luiz H.
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p. 1857 - 1862
(2007/10/02)
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- Regioselective bromination of activated aromatic substrates with N-bromosuccinimide over HZSM-5
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The nuclear as well as side-chain bromination of activated aromatic substrates has been achieved in high yields and substantial regioselectivity wiht N-Bromosuccinimide (NBS) over HZSM-5.
- Paul, Vincent,Sudalai,Daniel, Thomas,Srinivasan
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p. 7055 - 7056
(2007/10/02)
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- Structure and Reactivity of Isoannulated Heterocyclic Systems with 4n-? and (4n + 2)-? Electrons, XVIII. - Benzothiophenes with Symmetric Structure: Modified and Optimized Preparations by the S-Oxide Route
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Benzothiophenes (15) with symmetric structure have been prepared efficiently from 1,3-dihydrobenzothiophene 2-oxides (9) by reaction with aluminium oxide, by O-acylation with trifluoroacetic anhydride, or O-alkylation with methyl trifluoromethanesulfonate.The aromatization of the S-oxides 9 is achieved by O-functionalization, subsequent elimination, and consecutive deprotonation.
- Kreher, Richard P.,Kalischko, Juergen
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p. 645 - 654
(2007/10/02)
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- Reaction of Tosylamide Monosodium Salt with Bis(halomethyl) Compounds: An Easy Entry to Symmetrical N-Tosyl Aza Macrocycles
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A one-step, general procedure for a variety of N-tosyl aza macrocycles (including aza-crown ethers, pyridino- and bipyridino-aza-crown analogues, and azacyclophanes), by reaction of appropriate bis(halomethyl) precursors with tosylamide monosodium salt (TsNHNa) in N,N-dimethylformamide, is described.In polymethyl-substituted 2,11-diazacyclophane systems, the methyl substituents play an important role in inducing stereospecific ring closures.Thus, coupling of 1,4-bis(chloromethyl)-2,5-dimethylbenzene (15b) with TsNHNa produced only one of the two possible diastereomeric dimers, to which chiral structure 16db was assigned by means of the chiral Eu(dcm)3 shift reagent.This stereochemical assignment was confirmed by a single-crystal X-ray study on 16d.Detosylation of N-tosyl aza macrocycles to the free polyamino macrocycles by reductive (Na-NH3) or hydrolytic (90percent H2SO4) methods, followed by N-methylation (CH2O-HCO2H), was also accomplished in excellent yield.The 1H NMR spectra of 2,11-diazacyclophanes and 2,11-diaza(2,6)pyridinophanes are discussed in terms of conformation and conformational mobility.
- Bottino, Francesco,Grazia, Michele Di,Finocchiaro, Paolo,Fronczek, Frank R.,Mamo, Antonino,Pappalardo, Sebastiano
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p. 3521 - 3529
(2007/10/02)
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- The easy preparation of many benzylic bromides using molecular bromine as a halogenating in the presence of catalytic amounts of lanthanum tri-acetate
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Many benzylic brominations were easily achieved by molecular bromine in CCl4 in presence of 1 percent of La (OAc)3 and a standard room lighting lamp.The selectivity is excellent except for certain electron-rich systems (p-methylaniline, p-cresol).
- Ouertani, Mohsen,Girard, Pierre,Kagan, Henry B.
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p. 327 - 328
(2007/10/02)
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- 7-[[Amino(1,3-dihydrobenzo[c]thienyl)acetyl]amino]cephalosporin derivatives
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This invention is directed to new 7-[[amino(1,3-dihydrobenzo[c]thien-5-yl)acetyl]amino]cephalosporin derivatives useful as antibiotics.
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