- Antiplasmodial activity of [(aryl)arylsulfanylmethyl]pyridine
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A series of [(aryl)arylsufanylmethyl]pyridines (AASMP) have been synthesized. These compounds inhibited hemozoin formation, formed complexes (KD = 12 to 20 μM) with free heme (ferriprotoporphyrin IX) at a pH close to the pH of the parasite food vacuole, and exhibited antimalarial activity in vitro. The inhibition of hemozoin formation may develop oxidative stress in Plasmodium falciparum due to the accumulation of free heme. Interestingly, AASMP developed oxidative stress in the parasite, as evident from the decreased level of glutathione and increased formation of lipid peroxide, H2O2, and hydroxyl radical (·OH) in P. falciparum. AASMP also caused mitochondrial dysfunction by decreasing mitochondrial potential (ΔΨm) in malaria parasite, as measured by both flow cytometry and fluorescence microscopy. Furthermore, the generation of ·OH may be mainly responsible for the antimalarial effect of AASMP since ·OH scavengers such as mannitol, as well as spin trap α-phenyl-n- tertbutylnitrone, significantly protected P. falciparum from AASMP-mediated growth inhibition. Cytotoxicity testing of the active compounds showed selective activity against malaria parasite with selectivity indices greater than 100. AASMP also exhibited profound antimalarial activity in vivo against chloroquine resistant P. yoelii. Thus, AASMP represents a novel class of antimalarial. Copyright
- Kumar, Sanjay,Das, Sajal Kumar,Dey, Sumanta,Maity, Pallab,Guha, Mithu,Choubey, Vinay,Panda, Gautam,Bandyopadhyay, Uday
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- Pegylated triarylmethanes: Synthesis, antimicrobial activity, anti-proliferative behavior and in silico studies
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We describe herein the synthesis, characterization and biological studies of novel PEGylated triarylmethanes. Non-symmetrical and symmetrical triarylmethanes series have been synthesized by Friedel-Crafts hydroxyalkylation or directly from bisacodyl respectively followed by a functionalization with PEG fragments in order to increase bioavailability and biological effectiveness. The antimicrobial activity was investigated against Gram-positive and Gram-negative foodborne pathogens and against Candida albicans, an opportunistic pathogenic yeast. The anti-biocidal activity was also studied using Staphylococcus aureus as a reference bacterium. Almost all PEGylated molecules displayed an antifungal activity comparable with fusidic acid with MIC values ranging from 6.25 to 50 μg/mL. Compounds also revealed a promising antibiofilm activity with biofilm eradication percentages values above 80% for the best molecules (compounds 4d and 7). Compounds 7 and 8b showed a modest antiproliferative activity against human colorectal cancer cell lines HT-29. Finally, in silico molecular docking studies revealed DHFR and DNA gyrase B as potential anti-bacterial targets and in silico predictions of ADME suggested adequate drug-likeness profiles for the synthetized triarylmethanes.
- Abdmouleh, Fatma,Ali, Mamdouh Ben,Arbi, Mehdi El,Ferroud, Clotilde,Goya-Jorge, Elizabeth,Guenineche, Léna,Lagarde, Nathalie,Liagre, Bertrand,Martin, Frédérique,Ricco, Christophe,Riccobono, Charlotte,Veitía, Maité Sylla-Iyarreta
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supporting information
(2020/01/31)
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- Targeting the aryl hydrocarbon receptor with a novel set of triarylmethanes
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The aryl hydrocarbon receptor (AhR) is a chemical sensor upregulating the transcription of responsive genes associated with endocrine homeostasis, oxidative balance and diverse metabolic, immunological and inflammatory processes, which have raised the pharmacological interest on its modulation. Herein, a novel set of 32 unsymmetrical triarylmethane (TAM) class of structures has been synthesized, characterized and their AhR transcriptional activity evaluated using a cell-based assay. Eight of the assayed TAM compounds (14, 15, 18, 19, 21, 22, 25, 28) exhibited AhR agonism but none of them showed antagonist effects. TAMs bearing benzotrifluoride, naphthol or heteroaromatic (indole, quinoline or thiophene) rings seem to be prone to AhR activation unlike phenyl substituted or benzotriazole derivatives. A molecular docking analysis with the AhR ligand binding domain (LBD) showed similarities in the binding mode and in the interactions of the most potent TAM identified 4-(pyridin-2-yl (thiophen-2-yl)methyl)phenol (22) compared to the endogenous AhR agonist 5,11-dihydroindolo[3,2-b]carbazole-12-carbaldehyde (FICZ). Finally, in silico predictions of physicochemical and biopharmaceutical properties for the most potent agonistic compounds were performed and these exhibited acceptable druglikeness and good ADME profiles. To our knowledge, this is the first study assessing the AhR modulatory effects of unsymmetrical TAM class of compounds.
- Barigye, Stephen J.,Carpio, Laureano E.,Ferroud, Clotilde,Giner, Rosa M.,Goya-Jorge, Elizabeth,Gozalbes, Rafael,Loones, Nicolas,Rampal, Celine,Sylla-Iyarreta Veitía, Maité
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supporting information
(2020/10/02)
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- Ligand-Free Iridium-Catalyzed Dehydrogenative ortho C?H Borylation of Benzyl-2-Pyridines at Room Temperature
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A convenient and ligand-free iridium-catalyzed dehydrogenative ortho C?H borylation of benzyl-2-pyridines has been developed. The reaction proceeds smoothly at room temperature using pinacolborane as a borylating reagent in the presence of catalytic amount of [IrOMe(COD)]2. The reaction is compatible with many functional groups, providing a vast array of ortho borylated products in moderate to excellent yields with excellent selectivities. (Figure presented.).
- Yang, Yuhuan,Gao, Qian,Xu, Senmiao
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supporting information
p. 858 - 862
(2019/01/04)
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- Conformational Dynamics-Guided Loop Engineering of an Alcohol Dehydrogenase: Capture, Turnover and Enantioselective Transformation of Difficult-to-Reduce Ketones
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Directed evolution of enzymes for the asymmetric reduction of prochiral ketones to produce enantio-pure secondary alcohols is particularly attractive in organic synthesis. Loops located at the active pocket of enzymes often participate in conformational changes required to fine-tune residues for substrate binding and catalysis. It is therefore of great interest to control the substrate specificity and stereochemistry of enzymatic reactions by manipulating the conformational dynamics. Herein, a secondary alcohol dehydrogenase was chosen to enantioselectively catalyze the transformation of difficult-to-reduce bulky ketones, which are not accepted by the wildtype enzyme. Guided by previous work and particularly by structural analysis and molecular dynamics (MD) simulations, two key residues alanine 85 (A85) and isoleucine 86 (I86) situated at the binding pocket were thought to increase the fluctuation of a loop region, thereby yielding a larger volume of the binding pocket to accommodate bulky substrates. Subsequently, site-directed saturation mutagenesis was performed at the two sites. The best mutant, where residue alanine 85 was mutated to glycine and isoleucine 86 to leucine (A85G/I86L), can efficiently reduce bulky ketones to the corresponding pharmaceutically interesting alcohols with high enantioselectivities (~99% ee). Taken together, this study demonstrates that introducing appropriate mutations at key residues can induce a higher flexibility of the active site loop, resulting in the improvement of substrate specificity and enantioselectivity. (Figure presented.).
- Liu, Beibei,Qu, Ge,Li, Jun-Kuan,Fan, Wenchao,Ma, Jun-An,Xu, Yan,Nie, Yao,Sun, Zhoutong
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p. 3182 - 3190
(2019/05/15)
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- Triazole Ureas Act as Diacylglycerol Lipase Inhibitors and Prevent Fasting-Induced Refeeding
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Triazole ureas constitute a versatile class of irreversible inhibitors that target serine hydrolases in both cells and animal models. We have previously reported that triazole ureas can act as selective and CNS-active inhibitors for diacylglycerol lipases (DAGLs), enzymes responsible for the biosynthesis of 2-arachidonoylglycerol (2-AG) that activates cannabinoid CB1 receptor. Here, we report the enantio- and diastereoselective synthesis and structure-activity relationship studies. We found that 2,4-substituted triazole ureas with a biphenylmethanol group provided the most optimal scaffold. Introduction of a chiral ether substituent on the 5-position of the piperidine ring provided ultrapotent inhibitor 38 (DH376) with picomolar activity. Compound 38 temporarily reduces fasting-induced refeeding of mice, thereby emulating the effect of cannabinoid CB1-receptor inverse agonists. This was mirrored by 39 (DO34) but also by the negative control compound 40 (DO53) (which does not inhibit DAGL), which indicates the triazole ureas may affect the energy balance in mice through multiple molecular targets.
- Deng, Hui,Kooijman, Sander,Van Den Nieuwendijk, Adrianus M. C. H.,Ogasawara, Daisuke,Van der Wel, Tom,Van Dalen, Floris,Baggelaar, Marc P.,Janssen, Freek J.,Van Den Berg, Richard J. B. H. N.,Den Dulk, Hans,Cravatt, Benjamin F.,Overkleeft, Herman S.,Rensen, Patrick C. N.,Van der Stelt, Mario
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supporting information
p. 428 - 440
(2017/04/26)
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- PBr3-mediated unexpected reductive deoxygenation of α-aryl-pyridinemethanols: Synthesis of arylmethylpyridines
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PBr3-mediated reductive deoxygenation of α-aryl-pyridinemethanols to provide arylmethylpyridines is described, the alcohol substrate scope is explored, free radical trap TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) is introduced, and the hydrogen source of the methylene product is defined. The unexpected reaction enabled us to prepare previously inaccessible, novel EP1 antagonists.
- Nishigaya, Yosuke,Umei, Kentaro,Watanabe, Daisuke,Kohno, Yasushi,Seto, Shigeki
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supporting information
p. 1566 - 1572
(2016/03/01)
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- Rhodium Catalyzed Asymmetric Hydrogenation of 2-Pyridine Ketones
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Catalyzed by [Rh(COD)Binapine]BF4, the asymmetric hydrogenation of 2-pyridine ketones has been achieved with excellent enantioselectivities (enantiomeric excesses up to 99%) under mild conditions. This method is suitable for various kinds of 2-pyridine ketones and their derivatives. A number of enantiomerically pure chiral 2-pyridine-aryl/alkyl alcohols were prepared through hydrogenation, which can be used directly in organic synthesis.
- Yang, Hailong,Huo, Ningning,Yang, Ping,Pei, Hao,Lv, Hui,Zhang, Xumu
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p. 4144 - 4147
(2015/09/15)
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- Rhodium-catalyzed NH insertion of pyridyl carbenes derived from pyridotriazoles: A general and efficient approach to 2-picolylamines and imidazo[1,5-a]pyridines
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A general and efficient NH insertion reaction of rhodium pyridyl carbenes derived from pyridotriazoles was developed. Various NH-containing compounds, including amides, anilines, enamines, and aliphatic amines, smoothly underwent the NH insertion reaction to afford 2-picolylamine derivatives. The developed transformation was further utilized in a facile one-pot synthesis of imidazo[1,5-a]pyridines.
- Shi, Yi,Gulevich, Anton V.,Gevorgyan, Vladimir
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supporting information
p. 14191 - 14195
(2015/01/09)
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- Facile one-pot synthesis of [1,2,3]triazolo[1,5-a]pyridines from 2-acylpyridines by copper(II)-catalyzed oxidative N-N bond formation
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An efficient and simple method for the synthesis of various [1,2,3]triazolo[1,5-a]pyridines has been established. The method involves a copper(II)-catalyzed oxidative N-N bond formation that uses atmospheric oxygen as the terminal oxidant following hydrazonation in one pot. The use of ethyl acetate as the solvent dramatically promotes the oxidative N-N bond-formation reaction and enables the application of oxidative cyclization in the efficient one-pot reaction. A mechanism for the reaction was proposed on the basis of the results of a spectroscopic study. In the same pot: [1,2,3]Triazolo[1,5-a] pyridines are synthesized from the corresponding 2-acylpyridines by a one-pot method, consisting of hydrazonation followed by oxidative cyclization through copper(II)-catalyzed N-N bond formation (see scheme).
- Hirayama, Tasuku,Ueda, Satoshi,Okada, Takahiro,Tsurue, Norihiko,Okuda, Kensuke,Nagasawa, Hideko
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supporting information
p. 4156 - 4162
(2014/04/17)
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- Friedel-Crafts hydroxyalkylation through activation of a carbonyl group using AlBr3: An easy access to pyridyl aryl/heteroaryl carbinols
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Aromatic electrophilic substitution of aromatic/electron rich heteroaromatic compounds with AlBr3 activated aldehydes/ketone to afford pyridyl aryl/heteroaryl or diaryl carbinols is described. The strong electron donating group dictates the regiochemical outcome of the product.
- Harikrishnan, Adhikesavan,Selvakumar, Jayaraman,Gnanamani, Elumalai,Bhattacharya, Suman,Ramanathan, Chinnasamy Ramaraj
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supporting information
p. 563 - 567
(2013/04/10)
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- Ruthenium catalyzed hydrohydroxyalkylation of isoprene with heteroaromatic secondary alcohols: Isolation and reversible formation of the putative metallacycle intermediate
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Heteroaromatic secondary alcohols react with isoprene to form products of hydrohydroxyalkylation in the presence of ruthenium(0) catalysts generated from Ru3(CO)12 and tricyclohexylphosphine, enabling direct conversion of secondary to tertiary alcohols in the absence of premetalated reagents or stoichiometric byproducts. The putative oxaruthenacycle intermediate has been isolated and characterized, and reversible metallacycle formation has been demonstrated.
- Park, Boyoung Y.,Montgomery, T. Patrick,Garza, Victoria J.,Krische, Michael J.
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supporting information
p. 16320 - 16323
(2013/12/04)
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- Chiral organomagnesiates as dual reagents for bromine-magnesium exchange of 2-bromopyridine and access to chiral α-substituted 2-pyridylcarbinols
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New chiral ligand containing butyl and dibutylmagnesiates have been prepared from a range of ligands and their reactivity studied. The reagents were generally efficient in promoting the clean bromine-magnesium exchange of 2-bromopyridine at room temperature and the subsequent reaction with aldehydes to afford α-substituted 2-pyridylcarbinols in good yields. (R,R)-TADDOLate proved to be the best ligand, leading to acceptable to good enantioselectivities. To the best of our knowledge this is the first example of an organomagnesiate-induced halogen-metal exchange followed by an enantioselective addition.
- Catel, Delphine,Chevallier, Floris,Mongin, Florence,Gros, Philippe C.
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supporting information; experimental part
p. 53 - 57
(2012/02/06)
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- [1,2]-Wittig rearrangement of aromatic heterocycles
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Anionic rearrangement of diverse heteroaryl ethers is reported. In many cases, directed metallation followed by formal [1,2]-Wittig rearrangement provides heteroaryl carbinols in good yield.
- Yang, Jingyue,Wangweerawong, Apiwat,Dudley, Gregory B.
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scheme or table
p. 1603 - 1606
(2012/08/29)
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- Pyridylmagnesiates: Generation by bromine-metal exchange and enantioselective addition to aldehydes
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Butyl and dibutylmagnesiates incorporating chiral ligands have been prepared and their reactivity studied. The reagents were efficient to promote the clean bromine-magnesium exchange of azinyl bromides at room temperature and subsequent reaction with aldehydes affording pyridylcarbinols. (R,R)-TADDOL-based dibutylmagnesiate was the best reagent leading to acceptable to good enantioselectivities, depending on the substrate and on the aldehyde substitution. This is the first example of enantioselective addition of in situ generated pyridylmagnesiate to carbonyl electrophiles.
- Catel, Delphine,Payen, Olivier,Chevallier, Floris,Mongin, Florence,Gros, Philippe C.
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experimental part
p. 4018 - 4028
(2012/07/28)
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- Aryl aryl methyl thio arenes prevent multidrug-resistant malaria in mouse by promoting oxidative stress in parasites
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We have synthesized a new series of aryl aryl methyl thio arenes (AAMTAs) and evaluated antimalarial activity in vitro and in vivo against drug-resistant malaria. These compounds interact with free heme, inhibit hemozoin formation, and prevent Plasmodium falciparum growth in vitro in a concentration-dependent manner. These compounds concentration dependently promote oxidative stress in Plasmodium falciparum as evident from the generation of intraparasitic oxidants, protein carbonyls, and lipid peroxidation products. Furthermore, AAMTAs deplete intraparasite GSH levels, which is essential for antioxidant defense and survival during intraerythrocytic stages. These compounds displayed potent antimalarial activity not only in vitro but also in vivo against multidrug-resistant Plasmodium yoelii dose dependently in a mouse model. The mixtures of enantiomers of AAMTAs containing 3-pyridyl rings were found to be more efficient in providing antimalarial activity. Efforts have been made to synthesize achiral AAMTAs 17-23 and among them, compound 18 showed significant antimalarial activity in vivo
- Goyal, Manish,Singh, Priyanka,Alam, Athar,Kumar Das, Sajal,Shameel Iqbal, Mohd,Dey, Sumanta,Bindu, Samik,Pal, Chinmay,Kumar Das, Sanjit,Panda, Gautam,Bandyopadhyay, Uday
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scheme or table
p. 129 - 142
(2012/09/07)
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- Homoleptic zincate-promoted room-temperature halogen-metal exchange of bromopyridines
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Homoleptic lithium tri- and tetraalkyl zincates were reacted with a set of bromopyridines. Efficient and chemoselective bromine-metal exchanges were realized at room temperature with a substoichiometric amount of nBu 4ZnLi2·TMEDA reagent (1/3 equiv; TMEDA=N,N,N′,N′-tetramethylethylenediamine). This reactivity contrasted with that of tBu4ZnLi2·TMEDA, which was inefficient below one equivalent. DFT calculations allowed us to rationalize the formation of N...Li stabilized polypyridyl zincates in the reaction. The one-pot difunctionalization of dibromopyridines was also realized using the reagent stoichiometrically. The direct creation of C-Zn bonds in bromopyridines enabled us to perform efficient Negishi-type cross-couplings. Mild zincation! nBu4ZnLi2·TMEDA (in substoichiometric amounts) promoted efficient and chemoselective room-temperature bromine-metal exchange of a range of bromopyridines (see scheme). DFT calculations strongly supported the formation of a stabilized tripyridylzincate, which could be reacted with electrophiles or be directly involved in palladium-catalyzed cross-coupling reactions.
- Chau, Nguyet Trang Thanh,Meyer, Maxime,Komagawa, Shinsuke,Chevallier, Floris,Fort, Yves,Uchiyama, Masanobu,Mongin, Florence,Gros, Philippe C.
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experimental part
p. 12425 - 12433
(2011/01/05)
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- Synthesis of fluorescent 1,3-diarylated imidazo[1,5-α]pyridines: Oxidative condensation-cyclization of aryl-2-pyridylmethylamines and aldehydes with elemental sulfur as an oxidant
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Oxidative condensation - cyclization of aldehydes and aryl-2- pyridylmethylamines proceeded in the presence of a stoichiometric amount of elemental sulfur as an oxidant in the absence of catalyst. The reaction gave a variety of 1,3-diarylated imidazo[l,5-a]pyridines in good to high yields. The products showed fluorescence emission in a wavelength range of 454-524 nm. The quantum yields of 1,3-diarylated imidazopyridines were greatly improved compared to those of the parent 3-monosubstituted compounds.
- Shibahara, Fumitoshi,Sugiura, Rie,Yamaguchi, Eiji,Kitagawa, Asumi,Murai, Toshiaki
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supporting information; experimental part
p. 3566 - 3568
(2009/09/05)
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- [1,2]-Anionic rearrangement of 2-benzyloxypyridine and related pyridyl ethers
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(Chemical Equation Presented) An anionic rearrangement of 2-benzyloxypyridine is described. Pyridine-directed metalation of the benzylic carbon leads to 1,2-migration of pyridine via a postulated associative mechanism (addition/elimination). Several aryl pyridyl carbinols were obtained in high yields. A formal synthesis of carbinoxamine, an antihistamine drug used for the treatment of seasonal allergies and hay fever, emerges from this methodology.
- Yang, Jingyue,Dudley, Gregory B.
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supporting information; experimental part
p. 7998 - 8000
(2010/03/01)
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- Slow-onset, long-duration, alkyl analogues of methylphenidate with enhanced selectivity for the dopamine transporter
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Methylphenidate analogues, in which the carbomethoxy has been replaced by an alkyl group and with different phenyl substituents, have been synthesized and tested in monoamine transporter assays. As predicted from a pharmacophore model, most of the RR/SS diastereomers showed high potency as dopamine reuptake inhibitors. Analogues with a 4-chlorophenyl group and an unbranched initial alkyl atom had consistently enhanced selectivity for the dopamine transporter. The most potent compounds were those with a three- or four-carbon chain. The "inactive" RS/SR diastereomers showed substantial activity when the phenyl substituent was 3,4-dichloro. On a locomotor assay, one compound was found to have a slow onset and a long duration of action. The activity of these compounds provides additional evidence for a conformational/superposition model of methylphenidate with cocaine-like structures. A ketone analogue, obtained by hydrogenating a previously described vinylogous amide, had activity similar to that of methylphenidate.
- Froimowitz, Mark,Gu, Yonghong,Dakin, Les A.,Nagafuji, Pamela M.,Kelley, Charles J.,Parrish, Damon,Deschamps, Jeffrey R.,Janowsky, Aaron
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p. 219 - 232
(2007/10/03)
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- Convenient, benign and scalable synthesis of 2- and 4-substituted benzylpiperidines
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A short, scalable and environmentally benign synthesis of 2- and 4-substituted benzylpiperidines has been developed. The method is based on the temperature-programmed consecutive deoxygenation and heteroaromatic ring saturation of aryl(pyridin-2-yl)- and aryl(pyridin-4-yl)methanols and aryl(pyridin-4-yl)methanones in the presence of Pd/C catalyst. The crucial roles of the temperature, the acidity and the substrate structure in the change of selectivity have been demonstrated by isolation of several substituted aryl(piperidine)methanols. The carbinols and ketones were prepared from commercially available pyridinecarbaldehydes or 4-cyanopyridine and substituted bromobenzenes via organometallic intermediates. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Agai, Bela,Proszenyak, Agnes,Tarkanyi, Gabor,Vida, Laszlo,Faigl, Ferenc
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p. 3623 - 3632
(2007/10/03)
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- IPSO SUBSTITUTION OF HETEROCYCLIC TRIMETHYLSILYL CARBOXYLATES BY CARBON ELECTROPHILES
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Trimethylsilyl esters 1 of heterocyclic carboxylic acids having the ester group in the α-position to an azine nitrogen atom react with aldehydes or ketones through ipso substitution of the ester group to give (trimethylsiloxy)-alkyl-substituted heterocyclic products in good yields.
- Effenberger, Franz,Koenig, Joachim
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p. 3281 - 3288
(2007/10/02)
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- 3-SUBSTITUTED-4-HYDROXYPHENYL-2-PIPERIDYLCARBINOLS AS BETA ADRENERGIC STIMULANTS
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3-Substituted-3-hydroxyphenyl-2-piperidylcarbinols are prepared. These compounds are β-adrenergic stimulants and are useful in particular as bronchodilators.
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