- Novel photochemical rearrangements of dihydro-1,3-thiazines
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A series of 4-alkyl or 4-phenyl substituted 2,3-dihydro-6H-1,3-thiazine-5-carboxylates are synthesised and photolysed in toluene. The 4-methyl compound rearranges to a thiazolidine, which co-exists as an imino-tau tomer in solution. The 4-ethyl derivative
- Bhatia, Shameem H.,Buckley, David M.,McCabe, Richard W.,Avent, Anthony,Brown, Robert G.,Hitchcock, Peter B.
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Read Online
- A scaffold replacement approach towards new sirtuin 2 inhibitors
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Sirtuins (SIRT1–SIRT7) are an evolutionary conserved family of NAD+-dependent protein deacylases regulating the acylation state of ε-N-lysine residues of proteins thereby controlling key biological processes. Numerous studies have found association of the aberrant enzymatic activity of SIRTs with various diseases like diabetes, cancer and neurodegenerative disorders. Previously, we have shown that substituted 2-alkyl-chroman-4-one/chromone derivatives can serve as selective inhibitors of SIRT2 possessing an antiproliferative effect in two human cancer cell lines. In this study, we have explored the bioisosteric replacement of the chroman-4-one/chromone core structure with different less lipophilic bicyclic scaffolds to overcome problems associated to poor physiochemical properties due to a highly lipophilic substitution pattern required for achieve a good inhibitory effect. Various new derivatives based on the quinolin-4(1H)-one scaffold, bicyclic secondary sulfonamides or saccharins were synthesized and evaluated for their SIRT inhibitory effect. Among the evaluated scaffolds, the benzothiadiazine-1,1-dioxide-based compounds showed the highest SIRT2 inhibitory activity. Molecular modeling studies gave insight into the binding mode of the new scaffold-replacement analogues.
- Seifert, Tina,Malo, Marcus,Kokkola, Tarja,Stéen, E. Johanna L.,Meinander, Kristian,Wallén, Erik A.A.,Jarho, Elina M.,Luthman, Kristina
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- Donor-Acceptor-Acceptor 1,3-Bisdiazo Compounds: An Exploration of Synthesis and Stepwise Reactivity
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Metal carbenes, derived from the decomposition of diazo compounds, are valued for their capacity to perform a variety of transformations. A unique class of acyclic, bis-diazo compounds, the donor-acceptor-acceptor 1,3-bisdiazo compounds, are described her
- Abrams, Dylan J.,Davies, Huw M. L.,Sorensen, Erik J.
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supporting information
p. 1791 - 1795
(2020/03/24)
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- Homobenzylic Oxygenation Enabled by Dual Organic Photoredox and Cobalt Catalysis
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Activation of aliphatic C(sp3)-H bonds in the presence of more activated benzylic C(sp3)-H bonds is often a nontrivial, if not impossible task. Herein we show that leveraging the reactivity of benzylic C(sp3)-H bonds to achieve reactivity at the homobenzylic position can be accomplished using dual organic photoredox/cobalt catalysis. Through a two-part catalytic system, alkyl arenes undergo dehydrogenation followed by an anti-Markovnikov Wacker-type oxidation to grant benzyl ketone products. This formal homobenzylic oxidation is accomplished with high atom economy without the use of directing groups, achieving valuable reactivity that traditionally would require multiple chemical transformations.
- McManus, Joshua B.,Griffin, Jeremy D.,White, Alexander R.,Nicewicz, David A.
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supporting information
p. 10325 - 10330
(2020/07/27)
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- Discovery of [1,2,4]-triazolo [1,5-a]pyrimidine-7(4H)-one derivatives as positive modulators of GABAA1 receptor with potent anticonvulsant activity and low toxicity
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In searching for more effective and safer antiepileptic drugs, a series of 2,5-disubstituted [1,2,4]-triazolo[1,5-a]pyrimidine-7(4H)-one derivatives were designed and synthesized. Spontaneous Ca2+ oscillations (SCOs) of cortical neurons were used for in vitro phenotypic screening. Maximal electroshock test (MES) and pentylenetetrazole (PTZ) test were used to access their anticonvulsant activity, and rotarod test was used to estimate their neurotoxicity. The active compounds in in vitro model are specifically effective in pentylenetetrazole (PTZ)-induced epilepsy model but not maximal electroshock (MES) model, more importantly with lower neurotoxicity as compared to commonly used drugs. Among them, compound 5c and 5e showed significant anticonvulsant activities in PTZ-induced epilepsy model with ED50 values at 31.81 mg/kg and 40.95 mg/kg, respectively. These compounds have improved neurotoxicity with protective index (PI = TD50/ED50) values at 17.22 and 9.09, respectively. Finally we demonstrated that compound 5c and 5e mainly acted on GABAA receptor as positive modulators but not sodium channels. Thus the present study has provided potential candidates for further investigation in epilepsy.
- Huang, Longjiang,Ding, Jing,Li, Min,Hou, Zhipeng,Geng, Yanru,Li, Xiufen,Yu, Haibo
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- Replacement of the Benzylpiperidine Moiety with Fluorinated Phenylalkyl Side Chains for the Development of GluN2B Receptor Ligands
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The 4-benzylpiperidine moiety is a central structural element of potent N-methyl-d-aspartate (NMDA) receptor antagonists containing the GluN2B subunit. To obtain novel GluN2B ligands suitable for positron emission tomography, the benzylpiperidine moiety was replaced with fluorinated ω-phenylalkylamino groups. For this purpose three primary propyl- and butylamines 7 a–c and one butyraldehyde 7 d bearing a fluorine atom and an ω-phenyl moiety were prepared in 3- to 7-step syntheses. Compounds 7 a–d were attached to various scaffolds of potent GluN2B antagonists (scaffold hopping) instead of the original 4-benzylpiperidine moiety. Although benzoxazol-2-ones and indoles with a benzylpiperidine moiety show high GluN2B affinity, the corresponding fluorophenylalkylamine derivatives did not result in high Glu2B affinity. Moderate GluN2B affinity was observed for a 3-(fluoroalkyl)-substituted tetrahydro-1H-3-benzazepine (Ki=239 nm). However, high GluN2B affinity was obtained for the tetrahydro-5H-benzo[7]annulen-7-amines 12 a–c (Ki=17–30 nm). Docking studies resulted in the same binding pose for 12 a as for the lead compound Ro 25-6981. It can be concluded that some GluN2B ligands (benzoxazolones, indoles) do not tolerate replacement of the 4-benzylpiperidine moiety with flexible fluorinated phenylalkyl side chains, but other scaffolds such as tetrahydro-3-benzazepines and -benzo[7]annulenes retain interaction with NMDA receptors containing the GluN2B subunit.
- Thum, Simone,Schepmann, Dirk,Kalinin, Dmitrii V.,Ametamey, Simon M.,Wünsch, Bernhard
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p. 2522 - 2529
(2018/11/23)
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- TBHP/AIBN-Mediated Synthesis of 2-Amino-thioazoles from Active Methylene Ketones and Thiourea under Metal-free Conditions
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A new oxidative system of tert-butyl hydroperoxide (TBHP)/azodiisobutyronitrile (AIBN) has been used for the first time for a convenient, metal-free synthesis of substituted 2-aminothioazoles from active methylene ketone derivatives and thiourea. The reaction is postulated to proceed via an oxidative cyclization initiated by a radical process and followed by a condensation reaction.
- Sun, Jiyun,Ge, Huaibin,Zhen, Xiaohua,An, Xuechan,Zhang, Guangtao,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
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p. 2107 - 2114
(2018/03/26)
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- Oxa-Pictet–Spengler reaction as key step in the synthesis of novel σ receptor ligands with 2-benzopyran structure
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The Oxa-Pictet–Spengler reaction of methyl 3-hydroxy-4-phenylbutanoate (8) was explored to obtain novel σ receptor ligands. 1-Acyl protected piperidone ketals 10 and 11 reacted with phenylethanol 8 to yield spirocyclic compounds. Aliphatic aldehyde acetals 19 provided 1,3-disubstituted 2-benzopyrans 20 with high cis-diastereoselectivity. The intramolecular Oxa-Pictet–Spengler reaction of 24 led to the tricyclic compound 25. The spirocyclic compounds 18 show high σ1affinity (Ki20–26?nM) and σ1/σ2selectivity (>9-fold), when a large substituent (n-octyl, benzyl, phenylpropyl) is attached to the piperidine N-atom. Opening of the piperidine ring to yield aminoethyl (22, 23) or aminomethyl derivatives (21) resulted in reduced σ1affinity and σ1/σ2selectivity.
- Knappmann, Inga,Schepmann, Dirk,Wünsch, Bernhard
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p. 4045 - 4055
(2016/08/23)
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- Hauser-Heck: Efficient Synthesis of γ-Aryl-β-ketoesters en Route to Substituted Naphthalenes
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γ-Aryl-β-ketoesters can be prepared in one step from aryl bromides and bis(trimethylsilyl) enol ethers using catalytic amounts of Pd(dba)2/t-Bu3P and stoichiometric amounts of Bu3SnF. The wide range of γ-(hetero)aryl-β-ketoesters that can be obtained illustrate the scope and limitations of this novel Hauser-Heck combination. γ-Aryl-β-ketoesters with a 1,3-dioxane acetal in the ortho position can easily be transformed into the hydroxy naphthoate in very good yield. Aqueous formic acid at 65 °C provides optimal conditions for this deprotective aromatization.
- Wagner, Frederic,Harms, Klaus,Koert, Ulrich
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p. 5670 - 5673
(2015/12/08)
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- Total synthesis of (-)-ophiodilactone A and (-)-ophiodilactone B
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The first asymmetric total synthesis of (-)-ophiodilactone A and (-)-ophiodilactone B, isolated from the ophiuroid (Ophiocoma scolopendrina), is reported. The key features of the synthesis include the highly stereocontrolled construction of the structurally congested γ-lactone/δ-lactone skeleton through an asymmetric epoxidation, diastereoselective iodolactonization, and intramolecular epoxide-opening with a carboxylic acid, and biomimetic radical cyclization of ophiodilactone A to ophiodilactone B. Bioinspired synthesis: The first total synthesis of the title compounds has been accomplished in a highly stereocontrolled manner. Key features of the synthesis include an asymmetric epoxidation, a diastereoselective iodolactonization, an intramolecular epoxide opening with a carboxylic acid, and a biomimetic radical cyclization of ophiodilactone A to ophiodilactone B. Copyright
- Matsubara, Takaaki,Takahashi, Keisuke,Ishihara, Jun,Hatakeyama, Susumi
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supporting information
p. 757 - 760
(2014/01/23)
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- Highly atom-efficient oxidation of electron-deficient internal olefins to ketones using a palladium catalyst
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A 100 % atom-efficient synthesis of ketones from electron-deficient internal olefins was achieved using O2 as a "green" oxidant (see scheme, DMA=N,N-dimethylacetamide, EWG=electron-withdrawing group). Various electron-deficient olefins were oxidized to the corresponding ketones with over 99 % selectivity and without the formation of olefin isomers or their oxidized products. Copyright
- Mitsudome, Takato,Yoshida, Syuhei,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 5961 - 5964
(2013/06/27)
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- Stereoselective synthesis of the fused γ-lactone/ δ-lactone core of ophiodilactones
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A promising precursor of ophiodilactones A and B, tetrameric phenyl propanoids isolated form the ophiuroid Ophiocoma scolopendrina, has been synthesized stereoselectively employing a halolactonization and an intramolecular epoxide-opening with a carboxyli
- Matsubara, Takaaki,Takahashi, Keisuke,Ishihara, Jun,Hatakeyama, Susumi
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p. 155 - 158
(2013/08/23)
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- Triclorosilane-mediated stereoselective synthesis of β-amino esters and their conversion to highly enantiomerically enriched β-lactams
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A highly stereoselective trichlorosilane-mediated reduction of N-benzyl enamines was developed; the combination of a low cost, easy to make metal-free catalyst and an inexpensive chiral auxiliary allowed to perform the reaction on substrates with different structural features often with total control of the stereoselectivity. By easy deprotection through hydrogenolysis followed by conversion of β-aminoester to 2-azetidinones, the synthesis of enantiomerically pure β-lactams (>98% e.e.) was successfully accomplished.
- Guizzetti, Stefania,Benaglia, Maurizio,Bonsignore, Martina,Raimondi, Laura
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supporting information; experimental part
p. 739 - 743
(2011/04/22)
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- GLYCINE B ANTAGONISTS
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The invention relates to pyrazolopyrimidine derivatives as well as their pharmaceutically acceptable salts. The invention further relates to a process for the preparation of such compounds. The compounds of the invention are glycine B antagonists and are therefore useful for the control and prevention of various disorders, including neurological disorders.
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Page/Page column 57
(2010/12/29)
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- CHEMICAL COMPOUNDS
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The invention is directed to to substituted indazole derivatives. Specifically, the invention is directed to compounds according to Formula I: wherein R1 - R6 and X are defined herein. The compounds of the invention are inhibitors of PDK1 and can be useful in the treatment of disorders characterized by constitutively activated ACG kinases such as cancer and more specifically leukemia and cancers of the breast, colon, and lung. Accordingly, the invention is further directed to pharmaceutical compositions comprising a compound of the invention. The invention is still further directed to methods of inhibiting PDK1 activity and treatment of disorders associated therewith using a compound of the invention or a pharmaceutical composition comprising a compound of the invention.
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Page/Page column 128-129
(2010/11/04)
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- Expedient synthesis of 3-hydroxyisoquinolines and 2-hydroxy-1,4- naphthoquinones via one-pot aryne acyl-alkylation/condensation
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A convenient method is disclosed for the synthesis of both 3-hydroxyisoquinolines and 2-hydroxy-1,4-naphthoquinones from β-ketoesters using a one-pot aryne acyl-alkylation/condensation procedure. When performed in conjunction with a one-step method for the synthesis of the β-ketoester substrates, this method provides a new route to these polyaromatic structures in only two steps from commercially available carboxylic acid starting materials. The utility of this approach is demonstrated in the synthesis of the atropisomeric P,N-ligand, QUINAP. The Royal Society of Chemistry 2009.
- Allan, Kevin M.,Hong, Boram D.,Stoltz, Brian M.
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supporting information; experimental part
p. 4960 - 4964
(2010/02/15)
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- Regioselective synthesis of functionalized biaryls based on the first [3+3] cyclocondensations of 4-Aryl-1,3-bis(trimethylsilyloxy)buta-1,3-dienes
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Sterically encumbered biaryls were regioselectively prepared by formal [3+3] cyclocondensations of novel 4-aryl-1,3- bis(trimethylsilyloxy)-1,3-dienes. Georg Thieme Verlag Stuttgart · New York.
- Adeel, Muhammad,Rashid, Muhammad A.,Rasool, Nasir,Ahmad, Rasheed,Villinger, Alexander,Reinke, Helmut,Fischer, Christine,Langer, Peter
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experimental part
p. 243 - 250
(2009/06/27)
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- β-Keto esters derived from 2-(trimethylsilyl)ethanol: An orthogonal protective group for β-keto esters
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β-Keto esters derived from 2-(trimethylsilyl)ethanol undergo cleavage and decarboxylation when treated with 0.75 equivalents of tetrabutylammonium fluoride trihydrate in tetrahydrofuran at 50°C, while β-keto esters derived from methanol, tert-butyl alcohol, allyl alcohol, or benzyl alcohol stay intact. Conversely, methyl-, tert-butyl-, allyl-, or benzyl β-keto esters can be cleaved and decarboxylated without the 2-(trimethylsilyl)ethyl β-keto esters being affected. Similarly, mixed bis(β-keto esters) derived from 2-(trimethylsilyl)ethanol and methanol, tert-butyl alcohol, allyl alcohol, or benzyl alcohol can be defunctionalized chemoselectively under the same reaction conditions. Georg Thieme Verlag Stuttgart.
- Knobloch, Eva,Brueckner, Reinhard
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experimental part
p. 2229 - 2246
(2009/04/08)
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- Microwave assisted rapid and efficient synthesis of aryl methyl ketones and β-keto esters using Meldrum's acid
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Microwave mediated rapid and efficient synthesis of aryl methyl ketones and β-keto esters from acyl Meldrum's acid by hydrolysis and alcoholysis, respectively, has been reported.
- More,Mahulikar
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p. 823 - 825
(2007/10/03)
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- Small molecule inhibitors of bacterial quorum sensing and biofilm formation
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Bacteria monitor their local population densities using small molecules (or autoinducers) in a process known as quorum sensing. Here, we report a new and efficient synthetic route to naturally occurring bacterial autoinducers [N-acyl L-homoserine lactones (AHLs)] that is readily amenable to the synthesis of analogues. This route has been applied in the first synthesis of a library of non-native AHLs. Evaluation of these compounds in bacterial reporter gene and biofilm assays has revealed a potent set of quorum sensing antagonists. These ligands will serve as valuable new tools to explore the role of quorum sensing in bacterial pathogenesis. Copyright
- Geske, Grant D.,Wezeman, Rachel J.,Siegel, Adam P.,Blackwell, Helen E.
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p. 12762 - 12763
(2007/10/03)
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- One step synthesis of 1,2,3-triazole carboxylic acids
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Disclosed is a one step method for preparing a 1,2,3-triazole carboxylic acid by treating an azide with a β-ketoester in the presence of a base.
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- Ketone derivatives and medical application thereof
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The present invention relates to ketone derivatives represented by the following formula and medical agents containing the ketone derivatives or pharmacologically acceptable salts thereof as an active ingredient, and in particular, relates to a hematopoietic agent; it is shown that the present invention increases blood cells, such as platelets, white blood cells, and red blood cells, and is effective in preventing and treating cytopenia caused by cancer chemotherapy, radiation therapy, and the like.
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- Process for producing 3-oxocarboxylic acid esters
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A novel process for producing 3-oxocarboxylic acid esters, which are useful as intermediates in the synthesis of ceramides to be used as a humectant, biodegradable polymers, drugs, etc., at a high purity and a high yield without requiring any troublesome procedure, is disclosed. The process comprises reacting an acetoacetic ester with a calcium compound, a barium compound or a strontium compound in the presence of an organic solvent at a temperature of 10 to 120° C., further reacting the obtained product with a carboxylic acid chloride to thereby acylate it, and then adding thereto an alcohol in an amount 1 to 5 times by mol as much as the calcium compound, barium compound or strontium compound to thereby deacetylate the same.
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- Facile synthesis of β-keto esters from methyl acetoacetate and acid chloride: The barium oxide/methanol system
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The synthesis of β-keto esters has been performed in good yield by reacting excess methyl acetoacetate with barium oxide, acylating the resulting barium complex with acid chloride, and then cleaving the α-acyl β-keto ester with methanol at a mild temperature. Using this new procedure, various β-keto esters were prepared. Thus, methyl 4-phenyl-3-oxobutanoate, methyl 3-phenyl-3-oxopropionate, methyl 4-cyclohexyl-3-oxobutanoate, and methyl 3-oxooctadecanoate were prepared from methyl acetoacetate and the corresponding acid chloride in 69%, 84%, 67%, and 74% yields, respectively.
- Yuasa, Yoshifumi,Tsuruta, Haruki,Yuasa, Yoko
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p. 412 - 414
(2013/09/08)
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- Process for preparing optically active allophenylnorstatin derivatives
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A process for preparing an optically active (2S,3S)-allophenylnorstatin derivative (I) is disclosed, comprising asymmetrically hydrogenating a 4-phenyl-2-halogeno-3-oxobutyric ester (III) in the presence of a ruthenium-phosphine complex to obtain a 4-phen
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- Knoevenagel Reactions with β-Oxo Acids. Regiospecific Enol Equivalents for Syntheses of α,β-Unsaturated Ketones and of Some β-Ketols
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3-Oxobutanoic acid reacts with aliphatic aldehydes in the presence of pyridine to give α,β-unsaturated methyl ketones in good yields.Analogous results were obtained with a series of other β-oxo acids.Synthesis of (E)-7-methyloct-4-en-3-one, a major constituent of the marine sponge Plakortis zygompha, has been carried out using this methodology.Aromatic aldehydes are generally less reactive under these conditions but give β-ketols when the phenyl ring bears an electron-withdrawing substituent.Some observations on the mechanism of the reaction between 3-oxobutanoic acid and benzaldehyde are presented.
- Grayson, David H.,Tuite, Mathew R. J.
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p. 2137 - 2142
(2007/10/02)
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- Preparation and Rearrangement of cis-Methyl 3,4-Epoxy-4-(4'-methylphenyl)butanoate
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AlCl3 catalysed bromination of methyl 4-keto-4-(4'-methylphenyl)butanoate (2) is regioselective and furnishes methyl 3-bromo-4-keto-4-(4'-methylphenyl)butanoate (3). 3 on NaBH4 reduction in the presence of NaHCO3 furnishes a mixture of cis-methyl 3,4-epoxy-4-(4'-methylphenyl)butanoate (9), methyl (E)-4-hydroxy-4-(4'-methylphenyl)but-2-enoate (12), 4-(4'-methylphenyl)butanolide (26) and 2. 12 can be transformed to 1 on heating with NaOH-ethanol.BF3 catalysed rearrangement of 9 furnishes methyl 3-keto-4-(4'-methylphenyl)butanoate (17).The sequence of reactions 2->3->9->17 constitutes an interesting example of ketone transposition and provides a convenient route for the preparation of 17 from the readily available 2.
- Bhat, K. S.,Rao, A. S.
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p. 355 - 358
(2007/10/02)
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