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1.
Mark Mikuls Christian Mller Sybille Rust Frank Wierschem Patrick Amrhein Karola Rück‐Braun 《Advanced Synthesis \u0026amp; Catalysis》2000,342(8):791-803
A reaction sequence furnishing cyclic β‐[η5‐C5H5(CO)2Fe]‐substituted enals 5 starting from β‐keto esters 1 is described. Organolithiums were found to react smoothly with the iron‐substituted enals yielding α,β‐butenolides 6 by an intramolecular cyclocarbonylation of the lithiumalkoxide initially formed. The influence of e.g. the reaction temperature and the solvent on the reaction cascade is discussed. A reaction mechanism is proposed. 相似文献
2.
Zhenhua Gu Youqian Deng Wei Shu Shengming Ma 《Advanced Synthesis \u0026amp; Catalysis》2007,349(10):1653-1656
An efficient protocol for the highly regio‐ and stereoselective synthesis of 4‐(3′‐hydroxy‐2′‐iodoalk‐1′(Z)‐enyl)furan‐2(5H)‐one derivatives via selective iodohydroxylation of non‐heteroatom‐substituted allenes, i.e., 4‐allenyl‐2(5H)furanones, has been developed. The regio‐ and stereoselectivity of this reaction may be controlled by the electronic and steric effects of the furanone ring. 相似文献
3.
Steven Hostyn Gitte VanBaelen Guy L.F. Lemire Bert U.W. Maes 《Advanced Synthesis \u0026amp; Catalysis》2008,350(16):2653-2660
9H‐α‐Carbolines have been prepared via consecutive intermolecular Buchwald–Hartwig reaction and Pd‐catalyzed intramolecular direct arylation from commercially available 2,3‐dichloropyridines and substituted anilines. The combination of a high reaction temperature (180 °C) and the use of DBU were found to be crucial for the intramolecular direct arylation reactions of the 3‐chloro‐N‐phenylpyridin‐2‐amines as no reaction was observed at 120 °C and 180 °C using different inorganic and other organic bases. On the other hand, nitrogen‐methylated pyridine analogues of these substrates {N‐[3‐chloro‐1‐methylpyridin‐2(1H)‐ylidene]anilines} do undergo ring closure at 120 °C, with K3PO4 as base, affording the respective 1‐methyl‐1H‐α‐carbolines in good yields. 相似文献
4.
Bian Wu Wiktor Szymanski Dr. Piet Wietzes Stefaan de Wildeman Dr. Gerrit J. Poelarends Dr. Ben L. Feringa Prof. Dr. Dick B. Janssen Prof. Dr. 《Chembiochem : a European journal of chemical biology》2009,10(2):338-344
The phenylalanine aminomutase (PAM) from Taxus chinensis catalyses the conversion of α‐phenylalanine to β‐phenylalanine, an important step in the biosynthesis of the N‐benzoyl phenylisoserinoyl side‐chain of the anticancer drug taxol. Mechanistic studies on PAM have suggested that (E)‐cinnamic acid is an intermediate in the mutase reaction and that it can be released from the enzyme's active site. Here we describe a novel synthetic strategy that is based on the finding that ring‐substituted (E)‐cinnamic acids can serve as a substrate in PAM‐catalysed ammonia addition reactions for the biocatalytic production of several important β‐amino acids. The enzyme has a broad substrate range and a high enantioselectivity with cinnamic acid derivatives; this allows the synthesis of several non‐natural aromatic α‐ and β‐amino acids in excellent enantiomeric excess (ee >99 %). The internal 5‐methylene‐3,5‐dihydroimidazol‐4‐one (MIO) cofactor is essential for the PAM‐catalysed amination reactions. The regioselectivity of amination reactions was influenced by the nature of the ring substituent. 相似文献
5.
8‐Benzyltetrahydropyrazino[2,1‐f]purinediones: Water‐Soluble Tricyclic Xanthine Derivatives as Multitarget Drugs for Neurodegenerative Diseases 下载免费PDF全文
Dr. Andreas Brunschweiger Dr. Pierre Koch Dr. Miriam Schlenk Dr. Felipe Pineda Dr. Petra Küppers Dr. Sonja Hinz Dr. Meryem Köse Dr. Stefan Ullrich Dr. Jörg Hockemeyer Prof. Dr. Michael Wiese Dr. Jag Heer Prof. Dr. Christa E. Müller 《ChemMedChem》2014,9(8):1704-1724
8‐Benzyl‐substituted tetrahydropyrazino[2,1‐f]purinediones were designed as tricyclic xanthine derivatives containing a basic nitrogen atom in the tetrahydropyrazine ring to improve water solubility. A library of 69 derivatives was prepared and evaluated in radioligand binding studies at adenosine receptor (AR) subtypes and for their ability to inhibit monoamine oxidases (MAO). Potent dual‐target‐directed A1/A2A adenosine receptor antagonists were identified. Several compounds showed triple‐target inhibition; one of the best compounds was 8‐(2,4‐dichloro‐5‐fluorobenzyl)‐1,3‐dimethyl‐6,7,8,9‐tetrahydropyrazino[2,1‐f]purine‐2,4(1H,3H)‐dione ( 72 ) (human AR: Ki A1 217 nM , A2A 233 nM ; IC50 MAO‐B: 508 nM ). Dichlorinated compound 36 [8‐(3,4‐dichlorobenzyl)‐1,3‐dimethyl‐6,7,8,9‐tetrahydropyrazino[2,1‐f]purine‐2,4(1H,3H)‐dione] was found to be the best triple‐target drug in rat (Ki A1 351 nM , A2A 322 nm; IC50 MAO‐B: 260 nM ), and may serve as a useful tool for preclinical proof‐of‐principle studies. Compounds that act at multiple targets relevant for symptomatic as well as disease‐modifying treatment of neurodegenerative diseases are expected to show advantages over single‐target therapeutics. 相似文献
6.
A new approach for the synthesis of novel annulated‐pyrazoles is presented. This protocol includes an intermolecular condensation followed by a copper‐mediated intramolecular C N or C O coupling reaction. The method is applied to a range of substituted 4‐iodopyrazolecarbaldehydes which react with 1,2‐phenylenediamines or 2‐aminophenols to yield substituted 2,4‐ or 1,4‐dihydrobenzo[b]pyrazolo[4,3‐e][1,4]diazepines or substituted‐2H‐ or 1H‐benzo[b]pyrazolo[3,4‐f][1,4]oxazepines, respectively. 相似文献
7.
Agustí Bueno Malgorzata Rosol Jasn García Albert Moyano 《Advanced Synthesis \u0026amp; Catalysis》2006,348(18):2590-2596
The first non‐enzymatic kinetic resolution of planar chiral ferrocenes has been achieved by the Sharpless catalytic asymmetric dihydroxylation (AD) of a set of racemic 2‐substituted 1‐ethenylferrocenes 1a – d . The enantioselectivity factor krel varies from 20 to 62 [for (DHQD)2PYR ligands], and from 5 to 27 [for (DHQ)2PYR ligands]. The stereochemical outcome of the resolution can be easily predicted by the mnemonic device for AD, with the additional hypothesis that in the preferred transition state the olefin group and the upper cyclopentadiene ring of vinylferrocenes exhibit an essentially coplanar geometry. 相似文献
8.
Synthesis,chemical, and thermoelectric properties of n‐type π‐conjugated polymer composed of 1,2,4‐triazole and pyridine rings and its metal complexes 下载免费PDF全文
A soluble n‐type π‐conjugated polymer ( polymer 1 ) composed of a 1,2,4‐triazole ring substituted by a 4‐n‐octylphenyl subunit at the 4‐position of the 1,2,4‐triazole ring and pyridine‐2,5‐diyl rings was synthesized by Ni(cod)2 (cod = 1,5‐cyclooctadiene) promoted dehalogenation polycondensation of 3,5‐bis(2‐bromopyridyl)‐4‐n‐octylphenyl‐1,2,4‐triazole ( monomer 1 ). A polymer complex ( polymer‐BiCl3 ) was synthesized by the reaction of polymer 1 with BiCl3. The UV–vis spectrum of polymer 1 exhibited an absorption maximum (λmax value) at a longer wavelength than that exhibited by monomer 1 revealing that its π‐conjugation system was expanded along the polymer chain. Polymer 1 was electrochemically active in film, and the electrochemical reaction was accompanied with electrochromism. Thermoelectoric properties of polymer 1 and polymer‐BiCl3 were investigated. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39928. 相似文献
9.
The ytterbium(III) triflate [Yb(OTf)3]‐catalyzed diastereoselective cascade reaction of m‐N,N‐dimethylaminophenyl α,β‐unsaturated carbonyls with cyclopropane 1,1‐diesters under mild reaction conditions afforded highly substituted cis‐ and trans‐tetralins. The reaction of m‐N,N‐dimethylaminophenyl α,β‐unsaturated ketones with cyclopropane 1,1‐diesters provided tetralins with a trans orientation of the 1,4‐substitutents on the cyclohexyl ring; cis‐tetralins were obtained from m‐N,N‐dimethylaminophenyl substituted methylidenemalonates with high diastereoselectivities.
10.
A series of yttrium trisalicylaldimine complexes formed in situ by the reaction of trialkyl complex [Y(CH2SiMe3)3(THF)2] (THF is tetrahydrofuran) with three equivalent salicylaldimines were used as initiators for the ring‐opening polymerization of ε‐caprolactone. Electronic and steric effects of the salicylaldimine ligand played important roles on the catalytic properties of the yttrium complexes. The yttrium trisalicylaldimine complex Y( L7 )3 ( L7 = (S)‐2,4‐di‐tert‐butyl‐6‐[(1‐phenylethylimino)methyl]phenol) most effectively initiated controlled ring‐opening polymerization of ε‐caprolactone to prepare poly(ε‐caprolactone)s with high molecular weights and moderate molecular weight distributions. Obtained by density functional theory calculations, the optimized geometries of the four different active centers with four salicylaldimine ligands explained the experimental results. Copyright © 2011 Society of Chemical Industry 相似文献
11.
A. Stephen K. Hashmi Weibo Yang Frank Rominger 《Advanced Synthesis \u0026amp; Catalysis》2012,354(7):1273-1279
An unprecedented rearrangement/anellation sequence allows the clean synthesis of azepino[3,4‐b]indol‐1‐ones from readily available starting materials. Alkyne‐substituted indole‐3‐carboxamides were prepared and converted to azepino[3,4‐b]indol‐1‐ones by the SPhosAuNTf2 catalyst (SPhos=2‐dicyclohexylphosphino‐2′,6′‐dimethoxybiphenyl). The new connectivity, which involves an unprecedented 3,2‐shift of an acylamino group for the product formation, was proven by a crystal structure analysis. 相似文献
12.
Qian Chen Takahiro Soeta Masami Kuriyama Ken‐ichi Yamada Kiyoshi Tomioka 《Advanced Synthesis \u0026amp; Catalysis》2006,348(18):2604-2608
Catalytic asymmetric conjugate arylation of racemic 6‐substituted cyclohexenones with arylboronic acids was catalyzed by 3 mol % of chiral amidophosphane‐[RhCl(C2H4)]2 in a 10:1 mixture of 1,4‐dioxane and water at 70 °C to afford a nearly 1:1 mixture of trans‐ and cis‐5‐aryl‐2‐substituted cyclohexanones in high enantioselectivity, which was subsequently epimerized with sodium ethoxide in ethanol to give thermodynamically stable trans‐5‐aryl‐2‐substituted cyclohexanones with 99–97 % ee in high two‐step yields. 相似文献
13.
Jin‐Hong Fan Hong‐Wu Wang De‐Li Wu Zhi‐Gang Liu Lu‐Ming Ma 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2011,86(10):1295-1302
BACKGROUND: Little attention has been paid to the use of large‐sized scrap cast iron for reduction of refractory organic pollutants at neutral pH and in the presence of dissolved oxygen (DO). RESULTS: Scrap cast iron and copper‐modified cast iron with fresh surfaces have a high reactivity towards the reduction of 2,4‐dinitrotoluene (2,4‐DNT). The extent of conversion reached around 80% and 97% respectively, though it gradually decreased with repeated reactions to relatively stable values of 63% and 72%, and recovered once the reacted filings were cleaned by dilute acid. After 50 days reaction, no dissolved copper appeared in the copper‐modified cast iron process. The mass loss of copper due to physical detachment reached 1.1% of the total coated copper within the initial 20 reaction days, and only 0.3% appeared in the next 30 days. 2,4‐DNT oxidizes scrap cast iron to generate mainly FeFe2O4 with DO, however, it oxidizes scrap copper‐modified cast iron to generate mainly γ‐FeO(OH) and α‐FeO(OH). CONCLUSION: Both samples of cast iron were successfully applied in the treatment of neutral wastewater containing 2,4‐DNT with high reactivity and good repeatable efficiency. Electrode reaction rate was enhanced by the deposited copper, which has strong chemical and physical stability. Copyright © 2011 Society of Chemical Industry 相似文献
14.
Synthesis, σ Receptor Affinity,and Pharmacological Evaluation of 5‐Phenylsulfanyl‐ and 5‐Benzyl‐Substituted Tetrahydro‐2‐benzazepines 下载免费PDF全文
Dr. Peer Hasebein Bastian Frehland Dr. Dirk Schepmann Prof. Dr. Bernhard Wünsch 《ChemMedChem》2014,9(8):1697-1703
In accordance with a novel strategy for generating the 2‐benzazepine scaffold by connecting C6–C1 and C3–N building blocks, a set of 5‐phenylsulfanyl‐ and 5‐benzyl‐substituted tetrahydro‐2‐benzazepines was synthesized and pharmacologically evaluated. Key steps of the synthesis were the Heck reaction, the Stetter reaction, a reductive cyclization, and the introduction of diverse N substituents at the end of the synthesis. High σ1 affinity was achieved for 2‐benzazepines with linear or branched alk(en)yl residues containing at least an n‐butyl substructure. The butyl‐ and 4‐fluorobenzyl‐substituted derivatives, (±)‐5‐benzyl‐2‐butyl‐2,3,4,5‐tetrahydro‐1H‐2‐benzazepine ( 19 b ) and (±)‐5‐benzyl‐2‐(4‐fluorobenzyl)‐2,3,4,5‐tetrahydro‐1H‐2‐benzazepine ( 19 m ), show high selectivity over more than 50 other relevant targets, including the σ2 subtype and various binding sites of the N‐methyl‐D ‐aspartate (NMDA) receptor. In the Irwin screen, 19 b and 19 m showed clean profiles without inducing considerable side effects. Compounds 19 b and 19 m did not reveal significant analgesic and cognition‐enhancing activity. Compound 19 m did not have any antidepressant‐like effects in mice. 相似文献
15.
The reaction of N‐(2,4‐dinitrophenyl)pyridinium chloride ( 1 ), diaza‐18‐crown 6‐ether (DA18C6) and 2,5‐bis(aminophenyl)‐1,3,4‐oxadiazole ( 2 ) caused the opening of the pyridinium ring and yielded an ionic oligomer (oligomer‐1) comprising a 5‐DA18C6‐penta‐2,4‐dienylideneammonium chloride main chain and 2‐(4‐aminophenyl)‐5‐phenyl‐1,3,4‐oxadiazole or 2‐(4‐N‐phenylpyridinium)‐5‐phenyl‐1,3,4‐oxadiazole end groups. Accordingly, the reaction of 1 , DA18C6 and 2,7‐diaminofluorene ( 3 ) yielded oligomer‐2. The structures of oligomer‐1 and oligomer‐2 were determined by comparing their 1H NMR spectra with those of model compounds, which were synthesized by the 1:1 reaction of 1 with 2 or 3 . Oligomer‐1 and oligomer‐2 exhibited weak bluish‐green photoluminescence (PL) before the inclusion of Ag+ in the DA18C6 receptor, after which they exhibited strong bluish‐green PL. These observations can be explained by the occurrence of photoinduced electron transfer in the oligomers. Copyright © 2011 Society of Chemical Industry 相似文献
16.
Tihomir Tomašić Nace Zidar Andreja Kovač Dr. Samo Turk Mihael Simčič Didier Blanot Dr. Manica Müller‐Premru Prof. Dr. Metka Filipič Prof. Dr. Simona Golič Grdadolnik Prof. Dr. Anamarija Zega Prof. Dr. Marko Anderluh Prof. Dr. Stanislav Gobec Prof. Dr. Danijel Kikelj Prof. Dr. Lucija Peterlin Mašič Prof. Dr. 《ChemMedChem》2010,5(2):286-295
Mur ligases participate in the intracellular path of bacterial peptidoglycan biosynthesis and constitute attractive, although so far underexploited, targets for antibacterial drug discovery. A series of hydroxy‐substituted 5‐benzylidenethiazolidin‐4‐ones were synthesized and tested as inhibitors of Mur ligases. The most potent compound 5 a was active against MurD–F with IC50 values between 2 and 6 μm, making it a promising multitarget inhibitor of Mur ligases. Antibacterial activity against different strains, inhibitory activity against protein kinases, mutagenicity and genotoxicity of 5 a were also investigated, and kinetic and NMR studies were conducted. 相似文献
17.
Rafa Kowalczyk Przemysaw J. Boratyski 《Advanced Synthesis \u0026amp; Catalysis》2016,358(8):1289-1295
Organocatalyzed highly stereoselective 1,4‐thia‐Michael addition of mercaptans to linear 2,4‐dienones and 2‐en‐4‐ynones was developed using Cinchona alkaloid‐based squaramides. Application of only 0.5–1 mol % loading afforded products in up to 98:2 e.r. and above 99:1 after a single recrystallization. The adducts of allyl mercaptan can be conveniently further transformed to new chiral 2‐substituted 2,5‐dihydrothiophenes by ring‐closing metathesis.
18.
2‐Substituted 6‐(Het)aryl‐7‐deazapurine Ribonucleosides: Synthesis,Inhibition of Adenosine Kinases,and Antimycobacterial Activity 下载免费PDF全文
Dr. Vincent Malnuit Dr. Lenka Poštová Slavětínská Dr. Petr Nauš Dr. Petr Džubák Prof. Marián Hajdúch Dr. Jiřina Stolaříková Dr. Jan Snášel Dr. Iva Pichová Prof. Dr. Michal Hocek 《ChemMedChem》2015,10(6):1079-1093
A series of 6‐(hetero)aryl‐ or 6‐methyl‐7‐deazapurine ribonucleosides bearing a substituent at position 2 (Cl, F, NH2, or CH3) were prepared by cross‐coupling reactions at position 6 and functional group transformations at position 2. Cytostatic, antiviral, and antimicrobial activity assays were performed. The title compounds were observed to be potent and selective inhibitors of Mycobacterium tuberculosis adenosine kinase (ADK), but not human ADK; moreover, they were found to be non‐cytotoxic. The antimycobacterial activities against M. tuberculosis, however, were only moderate. The reason for this could be due to either poor uptake through the cell wall or to parallel biosynthesis of adenosine monophosphate by the salvage pathway. 相似文献
19.
CherylL. Hill ChandraS. Verma Gideon Grogan 《Advanced Synthesis \u0026amp; Catalysis》2007,349(6):916-924
A series of 1‐alkylbicyclo[3.3.0]octane‐2,8‐diones was transformed by enzymatic retro‐Claisen reaction using recombinant 6‐oxocamphor hydrolase (OCH) overexpressed in Escherichia coli, to yield optically active 2,3‐substituted cyclopentanones with enantiomeric excesses of up to >95 %. Whilst the parent substrate, bicyclo[3.3.0]octane‐2,8‐dione 12 , was transformed only very slowly, derivatives 13, 14, 15, 16 and 30 with alkyl chains of varying length in the 1‐position were converted rapidly to optically active products with typically 82 % de and up to >95 % enantiomeric excess. The results confirm the apparent requirement of OCH for non‐enolisable diketone substrates, and offer a potential route to decorated cyclopentanone derivatives of multiple chiral centres. Computer modelling of 1‐methylbicyclo[3.3.0]octane‐2,8‐dione into the active site of OCH suggested that the bicyclic [3.3.0] series substrates were accommodated in the active site in similar orientation with the natural enzyme substrate, 6‐oxocamphor, and would thus yield the (2S,3S)‐product series. 相似文献
20.
Yoshinari Sawama Masahiro Masuda Ryosuke Nakatani Hiroki Yokoyama Yasunari Monguchi Toshifumi Dohi Yasuyuki Kita Hironao Sajiki 《Advanced Synthesis \u0026amp; Catalysis》2016,358(23):3683-3687
The iron(III) chloride‐catalyzed Friedel–Crafts arylation of 4‐aryl‐4‐methoxy‐2,5‐cyclohexadienones, which were easily prepared by the phenyliodine(III) diacetate (PIDA)‐mediated oxidation of 4‐arylphenols in methanol, proceeded site‐selectively to form meta‐terphenyl (2,4‐diarylphenol) derivatives in good yields. The subsequent PIDA‐mediated oxidation and iron(III) chloride‐catalyzed Friedel–Crafts arylation of the resulting products gave the corresponding 2,4,6‐triarylphenol derivatives. The present method provides useful highly substituted polyarylated compounds.