- Continuous flow magnesiation of functionalized heterocycles and acrylates with TMPMgCl·LiCl
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A flow procedure for the metalation of functionalized heterocycles (pyridines, pyrimidines, thiophenes, and thiazoles) and various acrylates using the strong, non-nucleophilic base TMPMgCl·LiCl is reported. The flow conditions allow the magnesiations to be performed under more convenient conditions than the comparable batch reactions, which often require cryogenic temperatures and long reaction times. Moreover, the flow reactions are directly scalable without further optimization. Metalation under flow conditions also allows magnesiations that did not produce the desired products under batch conditions, such as the magnesiation of sensitive acrylic derivatives. The magnesiated species are subsequently quenched with various electrophiles, thereby introducing a broad range of functionalities. Go with the flow: Flow conditions allow a practical metalation of functionalized heterocycles and various acrylates in the presence of the base TMPMgCl·LiCl (TMP=2,2,6,6-tetramethylpiperidyl). More convenient temperatures and very fast reaction times can usually be achieved by applying the flow conditions. Sensitive acrylic derivatives can be magnesiated under flow conditions. Furthermore, the flow reactions are readily scalable without further optimization.
- Petersen, Trine P.,Becker, Matthias R.,Knochel, Paul
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supporting information
p. 7933 - 7937
(2014/08/05)
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- A study on the BF3 directed lithiation of 3-chloro- and 3-bromopyridine
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The BF3-directed lithiation of 3-chloro- and 3-bromopyridine (1a and 1b, respectively) has been investigated. The reactions of 3-chloro- or 3-bromopyridine-BF3 adduct with LDA (1.3/1.1 equiv) followed by quenching with benzaldehyde or iodine exclusively gave the C-2 substituted products. However, when 2.2 equiv of LDA and dimethyl disulfide was used, a C-6 substituted product was obtained. Dilithiation of 1a and 1b has been studied with and without the involvement of BF3 complexation. The role of Lia?F(BF3) interactions has been investigated by experimental and DFT calculations.
- Dhau, Jaspreet S.,Singh, Amritpal,Kasetti, Yoganjaneyulu,Bhatia, Sonam,Bharatam, Parsad V.,Brand?o, Paula,Félix, Vítor,Singh, Kamal N.
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p. 10284 - 10291
(2013/11/19)
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- CHEMICAL COMPOUNDS
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The invention relates to sulfonamide derivatives, to their use in medicine, to compositions containing them, to processes for their preparation and to intermediates used in such processes. More particularly the invention relates to a new sulfonamide Nav1.7 inhibitors of formula (I): or a pharmaceutically acceptable salt thereof, wherein Het1, X, R1, R2, R3, R4 and R5 are as defined in the description. Nav 1.7 inhibitors are potentially useful in the treatment of a wide range of disorders, particularly pain
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Page/Page column 52
(2012/01/15)
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- Deprotonative metalation of chloro- and bromopyridines using amido-based bimetallic species and regioselectivity-computed CH acidity relationships
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A series of chloro- and bromopyridines have been deprotometalated by using a range of 2,2,6,6-tetramethylpiperidino-based mixed lithium-metal combinations. Whereas lithium-zinc and lithium-cadmium bases afforded different mono- and diiodides after subsequent interception with iodine, complete regioselectivities were observed with the corresponding lithium-copper combination, as demonstrated by subsequent trapping with benzoyl chlorides. The obtained selectivities have been discussed in light of the CH acidities of the substrates, determined both in the gas phase and as a solution in THF by using the DFT B3LYP method.
- Snegaroff, Katia,Nguyen, Tan Tai,Marquise, Nada,Halauko, Yury S.,Harford, Philip J.,Roisnel, Thierry,Matulis, Vadim E.,Ivashkevich, Oleg A.,Chevallier, Floris,Wheatley, Andrew E. H.,Gros, Philippe C.,Mongin, Florence
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experimental part
p. 13284 - 13297
(2012/02/03)
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- GLYCINE TRANSPORTER INHIBITOR
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The present invention provides a compound represented by the following formula or a pharmaceutically acceptable salt of the compound or a hydrate of the compound or the salt, which is useful for the prevention or treatment of diseases such as schizophreni
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Page/Page column 109
(2010/11/30)
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- Silyl-mediated halogen/halogen displacement in pyridines and other heterocycles
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Heating with bromotrimethylsilane converts 2-chloropyridine into 2-bromopyridine and 2-chloro-6-methylpyridine into 2-bromo-6-methylpyridine. Both 2-chloropyridines and 2-bromopyridines give the corresponding iodo compound when treated with in situ generated iodotrimethylsilane. Although 3- and 4-chloropyridine are completely inert, 2,4-dichloropyridine undergoes the halogen/halogen exchange simultaneously at the 2- and 4-position. Halogen displacement takes place exclusively at the 2-position with 2,3-dichloropyridine and 2,5-dichloropyridine. In agreement with the intermediacy of N-trimethylsilylpyridinium salts as a prerequisite for the occurrence of halogen exchange, neither 2-fluoropyridine and 2-fluoro-6-methylpyridine nor any 2,6-dihalopyridine reacts. Finally, bromine/chlorine and iodine/chlorine substitution can also be accomplished with 2-or 4-chloroquinoline, 1-chloroisoquinoline, 2-chloropyrimidine, chloropyrazine and 2,3-dichloroquinoxaline as substrates. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2002).
- Schlosser, Manfred,Cottet, Fabrice
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p. 4181 - 4184
(2007/10/03)
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- Coupling reaction of zirconacyclopentadienes with dihalonaphthalenes and dihalopyridines: A new procedure for the preparation of substituted anthracenes, quinolines, and isoquinolines
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Reactions of tetraiodobenzene with zirconacyclopentadienes, which were conveniently prepared from two alkynes (or diynes) and zirconocene complexes, afforded 1,2,3,4-tetrasubstituted diiodonaphthalene derivatives in good isolated yields. These 1,2,3,4-tetrasubstituted diiodonaphthalene derivatives could be converted to 1,2,3,4,5,6,7,8-octasubstituted anthracene derivatives by reaction with a second zirconacyclopentadiene. When the two zirconacyclopentadienes were different, unsymmetrical anthracenes such as 1,2,3,4-tetraethyl-5,6,7,8-tetraphenylanthracene (68% isolated yield) were obtained. On the other hand, treatment of a 2,3-dihalopyridine such as 2-bromo-3-iodopyridine with zirconacyclopentadienes gave 5,6,7,8-tetrasubstituted quinoline derivatives in good to high yields. 3,4-Dihalopyridines such as 4-chloro-3-iodopyridine reacted with zirconacyclopentadienes to afford 5,6,7,8-tetrasubstituted isoquinoline derivatives in good to high yields.
- Takahashi, Tamotsu,Li, Yanzhong,Stepnicka, Petr,Kitamura, Masanori,Liu, Yanjun,Nakajima, Kiyohiko,Kotora, Martin
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p. 576 - 582
(2007/10/03)
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- First regioselective c-2 lithiation of 3- and 4-chloropyridines
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We have shown that the BuLi/LiDMAE reagent promotes the clean and regioselective C2 lithiation of 3- and 4-chloropyridines, while other reagents such as LDA or BuLi/TMEDA lead to classical ortho lithiation products or mixtures of regioisomers. The method was successfully applied to the preparation of various reactive 2,3- and 2,4-disubstituted pyridines.
- Choppin, Sabine,Gros, Philippe,Fort, Yves
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p. 603 - 606
(2007/10/03)
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- REGIOSELECTIVE ORTHO-LITHIATION OF HALOPYRIDINES. SYNTHESES OF ORTHO-DISUBSTITUTED PYRIDINES AND A CONVENIENT GENERATION OF 3,4-PYRIDYNE
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The regioselective ortho-lithiation of 3-chloro- (4), 3-fluoro- (7), 3-bromo- (10), 2-chloro- (22), and 4-chloropyridine (25) with lithium diisopropylamide affords, after quenching with various electrophiles, the corresponding ortho-disubstituted pyridine
- Gribble, Gordon W.,Saulnier, Mark G.
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p. 151 - 169
(2007/10/02)
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- Regioselective ortho lithiation of halopyridines
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Regioselective ortho lithiation of 2-, 3-, and 4-halopyridines is achieved with lithium diisopropylamide (-78°, tetrahydrofuran) to afford, upon quenching with electrophilic reagents, 2,3- and 3,4-disubstituted pyridines in good to excellent yield.
- Gribble, Gordon W.,Saulnier, Mark G.
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p. 4137 - 4140
(2007/10/02)
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