- Structure-Activity Relationship Studies of Pyrimidine-4-Carboxamides as Inhibitors of N-Acylphosphatidylethanolamine Phospholipase D
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N-Acylphosphatidylethanolamine phospholipase D (NAPE-PLD) is regarded as the main enzyme responsible for the biosynthesis of N-acylethanolamines (NAEs), a family of bioactive lipid mediators. Previously, we reported N-(cyclopropylmethyl)-6-((S)-3-hydroxypyrrolidin-1-yl)-2-((S)-3-phenylpiperidin-1-yl)pyrimidine-4-carboxamide (1, LEI-401) as the first potent and selective NAPE-PLD inhibitor that decreased NAEs in the brains of freely moving mice and modulated emotional behavior [ Mock et al. Nat Chem. Biol., 2020, 16, 667-675 ]. Here, we describe the structure-activity relationship (SAR) of a library of pyrimidine-4-carboxamides as inhibitors of NAPE-PLD that led to the identification of LEI-401. A high-throughput screening hit was modified at three different substituents to optimize its potency and lipophilicity. Conformational restriction of an N-methylphenethylamine group by replacement with an (S)-3-phenylpiperidine increased the inhibitory potency 3-fold. Exchange of a morpholine substituent for an (S)-3-hydroxypyrrolidine reduced the lipophilicity and further increased activity by 10-fold, affording LEI-401 as a nanomolar potent inhibitor with drug-like properties. LEI-401 is a suitable pharmacological tool compound to investigate NAPE-PLD function in vitro and in vivo.
- Mock, Elliot D.,Kotsogianni, Ioli,Driever, Wouter P. F.,Fonseca, Carmen S.,Vooijs, Jelle M.,Den Dulk, Hans,Van Boeckel, Constant A. A.,Van Der Stelt, Mario
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p. 481 - 515
(2021/02/05)
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- Convenient Continuous Flow Synthesis of N-Methyl Secondary Amines from Alkyl Mesylates and Epoxides
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The first continuous flow process was developed to synthesize N-methyl secondary amines from alkyl mesylates and epoxides via a nucleophilic substitution using aqueous methylamine. A variety of N-methyl secondary amines were produced in good to excellent yields, including a number of bioactive compounds or their precursors. Up to 10.6 g (88% yield) of an N-methyl secondary amine was produced in 140 min process time. The amination procedure included an in-line workup, and the starting mesylate material was also produced in continuous flow from the corresponding alcohol. Finally, an in-line process combining the mesylate synthesis and nucleophilic substitution was developed.
- Lebel, Hélène,Mathieu, Gary,Patel, Heena
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p. 2157 - 2168
(2020/11/23)
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- PRODUCTION OF AMINES VIA A HYDROAMINOMETHYLATION REACTION USING IMINIUM REACTANTS
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Provided is a process for producing an amine via a hydroaminomethylation reaction of a non- aromatic C-C double bond, said process comprising a step of reacting a compound comprising a non-aromatic C-C double bond with an iminium ion in a solvent comprising an alcohol, wherein the iminium ion is represented by the following formula (I): wherein R1 and R2 are independently hydrogen or selected from the group consisting of an aliphatic hydrocarbon group which may be substituted, an aromatic hydrocarbon group which may be substituted, an aliphatic heterocyclic group which may be substituted, an aromatic heterocyclic group which may be substituted and of combinations thereof, such as an aralkyl group which may be substituted; and R1 and R2 may be bonded to each other to form a ring together with the nitrogen atom to which they are bound; and wherein R1 and R2 are not both hydrogen and at least one of R1 and R2 carries a hydrogen atom at a carbon atom in ex? position to the nitrogen atom of the iminium ion.
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Page/Page column 33-34
(2020/05/14)
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- A General Acid-Mediated Hydroaminomethylation of Unactivated Alkenes and Alkynes
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In comparison to the extensively studied metal-catalyzed hydroamination reaction, hydroaminomethylation has received significantly less attention despite its considerable potential to streamline amine synthesis. State-of-the-art protocols for hydroaminomethylation of alkenes rely largely on transition-metal catalysis, enabling this transformation only under highly designed and controlled conditions. Here we report a broadly applicable, acid-mediated approach to the hydroaminomethylation of unactivated alkenes and alkynes. This methodology employs cheap, readily available, and bench-stable reactants and affords the desired amines with excellent functional group tolerance and impeccable regioselectivity. The broad scope of this transformation, as well as mechanistic investigations and in situ domino functionalization reactions are reported.
- Kaiser, Daniel,Tona, Veronica,Gon?alves, Carlos R.,Shaaban, Saad,Oppedisano, Alberto,Maulide, Nuno
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supporting information
p. 14639 - 14643
(2019/09/17)
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- B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
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The first B(C6F5)3-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3 ? OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 2301 - 2308
(2019/01/30)
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- INHIBITORS OF N-ACYLPHOSPHATIDYLETHANOLAMINE PHOSPHOLIPASE D (NAPE-PLD)
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The invention relates to a compound of the formula (I) as novel inhibitor of N-acylphosphatidylethanolamine phospholipase D (NAPE-PLD), and to use thereof for the prophylaxis or treatment of diseases associated with NAPE-PLD. wherein in a ring A, X1 is N, or CR4; X2 is N or CR5; X3 is N or CH; with the proviso that at least one of X1 and X3 is N.
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- Fluoxetine Inhibits Enterovirus Replication by Targeting the Viral 2C Protein in a Stereospecific Manner
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Enteroviruses (family Picornaviridae) comprise a large group of human pathogens against which no licensed antiviral therapy exists. Drug-repurposing screens uncovered the FDA-approved drug fluoxetine as a replication inhibitor of enterovirus B and D speci
- Bauer, Lisa,Manganaro, Roberto,Zonsics, Birgit,Strating, Jeroen R. P. M.,El Kazzi, Priscila,Lorenzo Lopez, Moira,Ulferts, Rachel,Van Hoey, Clara,Maté, Maria J.,Langer, Thierry,Coutard, Bruno,Brancale, Andrea,Van Kuppeveld, Frank J. M.
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p. 1609 - 1623
(2019/08/20)
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- Synthesis of β-Chiral Amines by Dynamic Kinetic Resolution of α-Branched Aldehydes Applying Imine Reductases
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Imine reductases (IREDs) allow the one-step preparation of optically active secondary and tertiary amines by reductive amination of ketones. Until now, mainly α-chiral amines have been prepared by this route. In this study, we explored the possibility of synthesizing β-chiral amines, a class of compounds which is also frequently found as structural motif in pharmaceuticals but much more challenging to prepare due to the following reasons: (i) The aldehyde substrate already contains the chiral center and needs to be racemized to enable full conversion. (ii) Because the intermediate imine bears the stereo center two carbon atoms remote to the imine nitrogen, it is more challenging to achieve high enantioselectivity compared to α-chiral amine synthesis. For investigating the proof of concept, we first confirmed that different IREDs are able to convert a variety of α-branched aldehydes when combined with five different amine substrates. The IRED from Streptomyces ipomoeae was a suitable enzyme facilitating the dynamic kinetic resolution of 2-phenylpropanal and a substituted 2-methyl-3-phenylpropanal: the corresponding N-methylated β-chiral amines were obtained with '95 % conversion and 78 and 95 %ee. Other amines were formed with low to moderate enantiomeric excess. This exemplifies the potential of IREDs for the one-step synthesis of secondary β-chiral amines, but also the challenge to identify highly selective enzymes for a desired amine product.
- Matzel, Philipp,Wenske, Sebastian,Merdivan, Simon,Günther, Sebastian,H?hne, Matthias
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p. 4281 - 4285
(2019/08/20)
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- PRODUCTION OF AMINES VIA A HYDROAMINOALKYLATION REACTION
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Provided is a process for producing an amine via a hydroaminoalkylation reaction of a non-aromatic C-C double bond or C-C triple bond, said process comprising a step of reacting a compound comprising a non-aromatic C-C double bond or C-C triple bond with a reactive component which is obtainable by combining an aminal or a hemiaminal ether with an acidic medium comprising trifluoroacetic acid, wherein the aminal contains two amino groups independently selected from a secondary and a tertiary amino group that are linked by a methylene group wherein one hydrogen atom may be replaced by a further substituent, and at least one of the amino groups carries a hydrogen atom at a carbon atom bound in α-position to its nitrogen atom, and the hemiaminal ether contains a secondary or a tertiary amino group which carries a hydrogen atom at a carbon atom bound in α-position to its nitrogen atom, and the secondary or tertiary amino group is linked to an alkoxy group by a methylene group wherein one hydrogen atom may be replaced by a further substituent.
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Page/Page column 64-65; 71; 85
(2019/12/04)
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- Radical-mediated direct C-H amination of arenes with secondary amines
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Aryl dialkyl amines, valuable subunits of a wide range of effect chemicals, are accessed by intramolecular amination of aromatic C-H bonds employing UV photolysis of N-chloroamines. The reactions show good functional group tolerance and allow access to a range of fused and bridged polycyclic structures. The homogeneous reaction conditions allow for the one-pot conversion of secondary amines to their arylated derivatives. Experimental and theoretical evidence supports the involvement of electrophilic aminium radicals which react via direct ortho-attack on the arene.
- Cosgrove, Sebastian C.,Plane, John M. C.,Marsden, Stephen P.
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p. 6647 - 6652
(2018/08/23)
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- Selective Monomethylation of Amines with Methanol as the C1 Source
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The N-monomethyl functionality is a common motif in a variety of synthetic and natural compounds. However, facile access to such compounds remains a fundamental challenge in organic synthesis owing to selectivity issues caused by overmethylation. To address this issue, we have developed a method for the selective, catalytic monomethylation of various structurally and functionally diverse amines, including typically problematic primary aliphatic amines, using methanol as the methylating agent, which is a sustainable chemical feedstock. Kinetic control of the aliphatic amine monomethylation was achieved by using a readily available ruthenium catalyst at an adequate temperature under hydrogen pressure. Various substrates including bio-related molecules and pharmaceuticals were selectively monomethylated, demonstrating the general utility of the developed method.
- Choi, Geunho,Hong, Soon Hyeok
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supporting information
p. 6166 - 6170
(2018/04/30)
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- Design and synthesis of sulfonamidophenylethylureas as novel cardiac myosin activator
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To optimize the lead urea scaffold 1 and 2 as selective cardiac myosin ATPase activator, a series of urea derivatives have been synthesized to explore its structure activity relationship. Among them N,N-dimethyl-4-(2-(3-(3-phenylpropyl)ureido)ethyl)benzenesulfonamide (13, CMA = 91.6%, FS = 17.62%; EF = 11.55%), N,N-dimethyl-4-(2-(1-methyl-3-(3-phenylpropyl)ureido)ethyl)benzene sulfonamide (40, CMA = 52.3%, FS = 38.96%; EF = 24.19%) and N,N-dimethyl-4-(2-(3-methyl-3-(3-phenylpropyl)ureido)ethyl)benzenesulfonamide (41, CMA = 47.6%, FS = 23.19%; EF = 15.47%) proved to be efficient to activate the cardiac myosin in vitro and in vivo. Further the % change in ventricular cell contractility at 5 μM of 13 (47.9 ± 3.2), 40 (45.5 ± 2.4) and 41 (63.5 ± 2.2) showed positive inotropic effect in isolated rat ventricular myocytes. The potent compounds 13, 40, 41 were highly selective for cardiac myosin over skeletal and smooth muscle myosin, thus proving them these new urea derivatives is a novel scaffold for discovery of cardiac myosin activators for the treatment of systolic heart failure.
- Manickam, Manoj,Jalani, Hitesh B.,Pillaiyar, Thanigaimalai,Boggu, Pulla Reddy,Sharma, Niti,Venkateswararao, Eeda,Lee, You-Jung,Jeon, Eun-Seok,Son, Min-Jeong,Woo, Sun-Hee,Jung, Sang-Hun
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p. 1869 - 1887
(2017/12/28)
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- Dimethylamine as a Substrate in Hydroaminoalkylation Reactions
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Transition-metal-catalyzed hydroaminoalkylations of alkenes have made great progress over the last decade and are heading to become a viable alternative to the industrial synthesis of amines through hydroformylation of alkenes and subsequent reductive amination. In the past, one major obstacle of this progress has been an inability to apply these reactions to the most important amines, methylamine and dimethylamine. Herein, we report the first successful use of dimethylamine in catalytic hydroaminoalkylations of alkenes with good yields. We also report applicability for a variety of alkenes to show the tolerance of the reaction towards different functional groups. Additionally, we present a catalytic dihydroaminoalkylation reaction using dimethylamine, which has never been reported before.
- Bielefeld, Jens,Doye, Sven
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supporting information
p. 15155 - 15158
(2017/11/01)
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- Amidation of unactivated ester derivatives mediated by trifluoroethanol
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A catalytic amidation protocol mediated by 2,2,2-trifluoroethanol has been developed, facilitating the condensation of unactivated esters and amines, furnishing both secondary and tertiary amides. The complete scope and limitations of the method are described, along with modified conditions for challenging substrates such as acyclic secondary amines and chiral esters with retention of chiral integrity.
- McPherson, Christopher G.,Caldwell, Nicola,Jamieson, Craig,Simpson, Iain,Watson, Allan J. B.
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supporting information
p. 3507 - 3518
(2017/04/26)
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- Compounds with cardiac myosin activating function and pharmaceutical composition containing the same for treating or preventing heart failure
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The present invention relates to a compound having a cardiotonic activating function and a pharmaceutical composition containing the same. The composition comprising the compound according to the present invention is effective in preventing or treating heart failure. In addition, the compound is represented by chemical formula 2 or is pharmaceutically acceptable salt thereof.COPYRIGHT KIPO 2016
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Paragraph 1608; 1613; 1614
(2017/02/02)
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- Compounds with cardiac myosin activating function and pharmaceutical composition containing the same for treating or preventing heart failure
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Disclosed are a compound having cardiotonic activity and a pharmaceutical composition containing the same, and the composition containing the compound, according to the present invention, is useful for preventing and treating heart failure.COPYRIGHT KIPO 2016
- -
-
Paragraph 0880; 0887-0891
(2016/10/07)
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- An assembly of structurally diverse small and simple 5-aminomethylene derivatives of 2,4-thiazolidinedione and studies of their biological activity
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The synthesis of a novel series of substituted 5-(aminomethylene)thiazolidine-2,4-diones was achieved using a wide range of heterocyclic models derived from eight drug-like molecules. The primary aim of this study was to combine medicinally known, biologically active molecules bearing a 2° amine functionality, such as terbinafine, fluoxetine, atomoxetine, cetirizine, risperidone, aripiprazole, ziprasidone, and clopidogrel, with a thiazolidinedione ring via an amino-methylene linker. By targeting this synergistic approach to compounds with skeletal, functional, and stereochemical diversity, we have developed a simple synthetic concept to enrich the thiazolidinedione collection with various biological activities. The biological activities of the newly synthesized 5-(aminomethylene)thiazolidine-2,4-dione derivatives were explored. All compounds were found to have antibacterial activity, with compounds bearing pyridine or piperazine moieties showing good to excellent antibacterial activity. Compounds with piperazine moieties were also found to show good antifungal activity, whereas none of the synthesized compounds showed high cytotoxic activity.
- Mohanty, Sandeep,Reddy, Sandeep G.,Ramadevi,Karmakar, Arun Chandra
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p. 4037 - 4049
(2015/11/02)
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- One-pot anti-markovnikov hydroamination of unactivated alkenes by hydrozirconation and amination
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A one-pot anti-Markovnikov hydroamination of alkenes is reported. The synthesis of primary and secondary amines from unactivated olefins was accomplished in the presence of a variety of functional groups. Hydrozirconation, followed by amination with nitrogen electrophiles, provides exclusive anti-Markovnikov selectivity. Most products are isolated in high yields without the use of column chromatography.
- Strom, Alexandra E.,Hartwig, John F.
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p. 8909 - 8914
(2013/09/24)
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- Design, synthesis, and evaluation of novel small molecule inhibitors of the influenza virus protein NS1
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Influenza is a continuing world-wide public health problem that causes significant morbidity and mortality during seasonal epidemics and sporadic pandemics. The existing vaccination program is variably effective from year to year, and drug resistance to available antivirals is a growing problem, making the development of additional antivirals an important challenge. Influenza virus non-structural protein 1 (NS1) is the centerpiece of the viral response to the host interferon (IFN) system. NS1 was demonstrated previously to be a potential therapeutic target for antiviral therapy by the identification of specific small-molecule inhibitors. One inhibitory compound, NSC125044, was subjected to chemical evaluation. Initial synthetic work comprised simplifying the core structure by removing unwanted functionality and determination of key features important for activity. Several subclasses of molecules were designed and synthesized to further probe activity and develop the basis for a structure-activity relationship. Apparent potency, as judged by activity in virus replication assays, increased dramatically for some analogs, without cytotoxicity. Results suggest that the target binding site tolerates hydrophobic bulk as well as having a preference for weakly basic substituents.
- Jablonski, Joseph J.,Basu, Dipwanita,Engel, Daniel A.,Geysen, H. Mario
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experimental part
p. 487 - 497
(2012/02/15)
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- THERAPEUTIC AGENT FOR CEREBRAL INFARCTION
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The invention provides a therapeutic drug for ischemic stroke. The therapeutic drug has the formula (I) wherein each symbol is as defined herein, or a pharmacologically acceptable salt thereof, or a solvate thereof, as an active ingredient.
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- Synthesis, structure-activity relationships and molecular modeling studies of new indole inhibitors of monoamine oxidases A and B
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New monoamine oxidase inhibitors were synthesized as indole analogues of a previously reported pyrrole series. Several compounds were potent MAO-A (12, 17, 19-22, 31, 36, and 37) or MAO-B (14, 20, 24, 38, 44, and 46) inhibitors, and had Ki values in the nanomolar concentration range. In particular, 22 (Ki = 0.00092 μM, and SI = 68,478) was exceptionally potent and selective as MAO-A inhibitor. In molecular modeling studies, compounds 22, 24, 44, and 46 positioned the indole ring into an aromatic cavity of MAO-A, and established π-π stacking interactions with Tyr407, Tyr444, and FAD cofactor. However, only compound 22 was able to form hydrogen bonds with FAD, a finding which was in accordance with its potent anti-MAO-A activity. Conversely, 22/MAOB complex was highly unstable during the MD simulation.
- La Regina, Giuseppe,Silvestri, Romano,Gatti, Valerio,Lavecchia, Antonio,Novellino, Ettore,Befani, Olivia,Turini, Paola,Agostinelli, Enzo
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experimental part
p. 9729 - 9740
(2009/04/06)
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- The ruthenium-catalyzed reduction and reductive N-alkylation of secondary amides with hydrosilanes: Practical synthesis of secondary and tertiary amines by judicious choice of hydrosilanes
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(Chemical Equation Presented) A triruthenium cluster, (μ3, η2,η3,η5-acenaphthylene)Ru 3(CO)7 (1) catalyzes the reaction of secondary amides with hydrosilanes, yielding a mixture of secondary amines, tertiary amines, and silyl enamines. Production of secondary amines with complete selectivity is achieved by the use of higher concentration of the catalyst (3 mol %) and the use of bifunctional hydrosilanes such as 1,1,3,3-tetramethyldisiloxane. Acidic workup of the reaction mixture affords the corresponding ammonium salts, which can be treated with a base, providing a facile method for isolation of secondary amines with high purity. In contrast, tertiary amines are formed with high selectivity by using lower concentration of the catalyst (1 mol %) and polymeric hydrosiloxanes (PMHS) as reducing agent. Reduction with PMHS encapsulates the ruthenium catalyst and organic byproducts to the insoluble silicone resin. The two reaction manifolds are applicable to various secondary amides and are practical in that the procedures provide the desired secondary or tertiary amine as a single product. The product contaminated with only minimal amounts of ruthenium and silicon residues. On the basis of the products and observed side products as well as NMR studies a mechanistic scenario for the reaction is also described.
- Hanada, Shiori,Ishida, Toshiki,Motoyama, Yukihiro,Nagashima, Hideo
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p. 7551 - 7559
(2008/02/12)
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- Compounds with growth hormone releasing properties
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There are disclosed novel synthetic peptides of the general formula (I) Compounds of formula (I) stimulate the release of growth hormone from the pituitary in humans and animals. A method for increasing the rate and extent of growth of animals to increase their milk and wool production or for the treatment of ailments, and the use of the compounds of formula (I) for the preparation of medicaments, are also disclosed.
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- Fused imidazopyridine derivatives as antihyperlipidemic agents
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A novel compound of the formula: wherein ring Q is an optionally substituted pyridine ring; One of R0, R1and R2is —Y0—Z0, and the other tow groups are a hydrogen, a halogen, an optionally substituted hydroxy group, a hydrocarbon group that may be an optionally substituted hydrocarbon group or an acyl group; Y0is a bond or an optionally substituted bivalent hydrocarbon group; Z0is a basic group which may be bonded via oxygen, nitrogen, —CO—, —CS—, —SO2N(R3)— (where R3is hydrogen or an optionally substituted hydrocarbon group), or S(O)n(wherein n is to 0, 1 or 2); .........is a single bond or a double bond, or a salt thereof, which has an excellent LDL receptor up-regulating, blood-lipids lowering, blood-sugar lowering and diabetic complication-ameliorating activity.
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- Preparation of secondary amines by reductive animation with metallic magnesium
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A novel and efficient method for the preparation of secondary amines by reductive animation of carbonyl compounds with primary amines has been developed. The reduction, effected with metallic magnesium in methanol, utilizing triethylamine-acetic acid as a buffer, gave pure secondary amines, mostly in good yields (65-80%). No formation of tertiary amines or alcohols was observed. Use of ammonium acetate as an amino component gave primary amines in modest yields (ca. 50%), together with variable amounts of secondary amines. Enamines failed to undergo reduction. The method is inexpensive, relatively rapid, operationally simple and suitable for large-scale preparations. In addition, a simple method for separation of primary amines from secondary ones has been developed.
- Micovic, Ivan V.,Ivanovic,Roglic, Goran M.,Kiricojevic, Vesna D.,Popovic, Jelena B.
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p. 265 - 269
(2007/10/03)
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- Synthesis of metallohaptenes. An unexpected behavior of the "activated" ferrocenic ester towards secondary amines.
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Ferrocenoyl chloride FcCOCl 1 (Fc = C5H5FeC5H4-) reacts with primary or secondary amine drugs (amphetamine : a; desipramine : b; nortryptiline; c) to give the expected metallohaptenes 3a,b,c : FcCONRR'.The organometallic labeled compound 3a is also obtain
- Lavastre, Isabelle,Besancon, Jack,Moiese, Claude,Brossier, Pierre
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p. 188 - 195
(2007/10/02)
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- Central nervous system antiischemic agents
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A series of phenylalkylaminoalkyl derivatives of Formula I wherein Ar is naphtyl or phenyl; R1 is hydrogen, fluoro or R?CONH-; R2 is hydrogen or C?-? alkyl; R? is C?-? alkyl; R? is C?-? alkyl or phenyl-C?- ? alkyl; x is zero or the integers 1 and 2; m is
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- ACYLCYANAMIDES: VERSATILE SYNTHETIC INTERMEDIATES
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An improved general procedure for the preparation of acylcyanamides is described.Preliminary experiments have demonstrated that acylcyanamides exibit a rich chemistry.For example, acylcyanamides are easily converted into highly reactive dianions which, in
- Belletire, J. L.
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p. 2063 - 2072
(2007/10/02)
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- Hydride Transfer Reaction Products in the Aminomethylation of Styrene
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Aminomethylation of styrene with formaldehyde and dimethylamine leads to N-methylbenzenepropanamine (1), N-(3-phenylpropyl)benzenepropanamine (3), and α-methylenebenzenepropanal (4) as major products.The ratio of 1, 3 and 4 is considerably influenced by the ratio of the reactants.The best yield of 1 is obtained by using dimethylamine in excess.Styrene in excess favors the formation of 3, and equivalent amounts of reactants afford the best yield of 4.Using formaldehyde in excess leads to the complete N-methylation of 1 and 3.When styrene reacts with formaldehyde and diethylamine or diisopropylamine the most important aminomethylation products are N-ethylbenzenepropanamine (11) or N-isopropylbenzenepropanamine (12), respectively, and 3 and 4 in both cases.The formation of the major products in the aminomethylation of styrene can be explained by the hydride transfer mechanism represented earlier as one competing mechanism for the aminomethylation of certain bicyclic alkenes.The N-methylation of amine 1 and 3, when formaldehyde is used in excess, is due to Eschweiler methylation under aminomethylation conditions.
- Manninen, Kalle,Karjalainen, Aira
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p. 190 - 195
(2007/10/02)
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- Competing Hydride Transfer and Ene Reactions in the Aminoalkylation of 1-Alkenes with N,N-Dimethylmethyleniminium Ions. A Literature Correction
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A literature report that N,N-dimethylmethyleniminium ion (2) reacts with propylene and styrene to form unsaturated tertiary amines is shown to be incorrect.The major products are the secondary amines 1-(methylamino)butane and 1-(methylamino)-3-phenylpropane in which N-demethylation has occurred along with the saturation of the alkene.Analogous major products are formed with 1-butene, 1-hexene, 1-octene, 1-dodecene, 1-tetradecene, p-methylstyrene, and m-nitrostyrene as substrates.When the substrates are isobutylene, 2-ethyl-1-hexene, α-methylstyrene, and p-methoxystyrene, the major products are tertiary amines, but the secondary amines are also formed in smaller yields.The small yields of tertiary amines obtained in the cases of styrene and p-methylstyrene were increased by going from solvent acetic acid to acetonitrile and by increasing the branching of the alkyl groups on nitrogen.The internal olefins 5-decene and cyclohexene were far less reactive, giving only 3-4percent of amine products that were mainly tertiary in the former case and secondary in the latter.It is concluded that tertiary amine products are favored by an alkene structure and a solvent that favors the formation of a stable carbenium ion intermediate or a transition state with substantial carbenium ion character upon electrophilic attack of the iminium ion on the alkene.The secondary amine products are favored when a carbenium ion is of low stability and when the β-carbon atom of the olefin and/or the alkyl group attached to nitrogen is sterically unhindered; such hindrance decreases the rate of hydride ion transfer that is believed to occur in the production of secondary amines.
- Cohen, Theodore,Onopchenko, Anatoli
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p. 4531 - 4537
(2007/10/02)
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