- Sodiation of Arenes and Heteroarenes in Continuous Flow
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The first sodiations of (hetero)arenes in continuous flow using NaDA (sodium diisopropylamide) in Me2EtN are reported. This flow procedure enables sodiation of functionalized arenes and heteroarenes that decompose under batch-sodiation conditions. The resulting sodiated (hetero)arenes react instantly with various electrophiles, such as ketones, aldehydes, isocyanates, alkyl bromides, and disulfides, affording polyfunctionalized (hetero)arenes in high yields. Scale-up is possible without further optimization.
- Weidmann, Niels,Ketels, Marthe,Knochel, Paul
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supporting information
p. 10748 - 10751
(2018/07/30)
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- TRICYCLIC COMPOUNDS AS mPGES-1 INHIBITORS
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The present invention relates to tricyclic compounds of formula (I) or pharmaceutically acceptable salt thereof as mPGES-1 inhibitors. These compounds are inhibitors of the microsomal prostaglandin E synthase-1 (mPGES-1) enzyme and are therefore useful in the treatment of pain and/or inflammation from a variety of diseases or conditions, such as asthama, osteoarthritis, rheumatoid arthritis, acute or chronic pain and neurodegenerative diseases. (I)
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Page/Page column 55
(2012/09/10)
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- An aluminum ate base: Its design, structure, function, and reaction mechanism
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An aluminum ate base, i-Bu3Al(TMP)Li, has been designed and developed for regio- and chemoselective direct generation of functionalized aromatic aluminum compounds. Direct alumination followed by electrophilic trapping with I2, Cu/Pd-catalyzed C-C bond formation, or direct oxidation with molecular O2 proved to be a powerful tool for the preparation of 1,2- or 1,2,3-multisubstituted aromatic compounds. This deprotonative alumination using i-Bu3Al(TMP)Li was found to be effective in aliphatic chemistry as well, enabling regio- and chemoselective addition of functionalized allylic ethers and carbamates to aliphatic and aromatic aldehydes. A combined multinuclear NMR spectroscopy, X-ray crystallography, and theoretical study showed that the aluminum ate base is a Li/Al bimetallic complex bridged by the nitrogen atom of TMP and the α-carbon of an i-Bu ligand and that the Li exclusively serves as a recognition point for electronegative functional groups or coordinative solvents. The mechanism of directed ortho alumination reaction of functionalized aromatic compounds has been studied by NMR and in situ FT-IR spectroscopy, X-ray analysis, and DFT calculation. It has been found that the reaction proceeds with facile formation of an initial adduct of the base and aromatic, followed by deprotonative formation of the functionalized aromatic aluminum compound. Deprotonation by the TMP ligand rather than the isobutyl ligand was suggested and reasoned by means of spectroscopic and theoretical study. The remarkable regioselectivity of the ortho alumination reaction was explained by a coordinative approximation effect between the functional groups and the counter Li+ ion, enabling stable initial complex formation and creation of a less strained transition state structure.
- Naka, Hiroshi,Uchiyama, Masanobu,Matsumoto, Yotaro,Wheatley, Andrew E. H.,McPartlin, Mary,Morey, James V.,Kondo, Yoshinori
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p. 1921 - 1930
(2007/10/03)
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- Proton mobility in 2-substituted 1,3-dichlorobenzenes: "ortho" or "meta" metalation?
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Nine 1,3-dichlorobenzene congeners were selected as model compounds to assess the relative rates of proton abstraction from 4- and 5-positions ("ortho" vs. "meta" metalation). Using lithium 2,2,6,6-tetramethylpiperidide as the basic reagent, the chlorine-adjacent 4-position underwent metalation exclusively. In contrast, attack at the chlorine-remote 5-posi" tion became significant even in the case of moderately sized 2-substituents (such as dimethylamino or ethyl) when secbutyllithium was employed. The "ortho/para" (4-/5-) ratios ranged from 80:20 to 65:35. The more pronounced "meta-orienting" effect of silicon as opposed to carbon substituents can be attributed to dissimilarities in the n polarization of the aromatic ring. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Schlosser, Manfred,Heiss, Christophe,Marzi, Elena,Scopelliti, Rosario
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p. 4398 - 4404
(2007/10/03)
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- Metalation and derivatization of all six dichlorobenzotrifluorides: Site selectivities
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The metalation of 2,3-, 2,6-, 2,4- and 3,5-dichlorobenzotrifluorides can be readily effected with standard reagents such as lithium diisopropylamide, lithium 2,2,6,6-tetramethylpiperidide, and butyllithium at the chlorine-adjacent 4- and 3-positions and t
- Masson, Eric,Marzi, Elena,Cottet, Fabrice,Bobbio, Carla,Schlosser, Manfred
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p. 4393 - 4400
(2007/10/03)
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- Regio- and chemoselective direct generation of functionalized aromatic aluminum compounds using aluminum ate base
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A regio- and chemoselective direct method for generation of functionalized aromatic aluminum compounds through deprotonative directed ortho-alumination using triisobutyl(tetramethylpiperidino)aluminate (iBu3Al(TMP)Li), prepared by mixing of triisobutylaluminum (iBu3Al) and lithium tetramethylpiperidide (LTMP) in THF, has been developed. Deprotonative alumination of various functionalized benzenes with the use of iBu3Al(TMP)Li proved effective for the direct generation of various ortho-functionalized aluminum aromatic and heteroaromatic derivatives, particularly those with electrophilic functional groups such as cyano, amide, and halogen. Direct alumination, followed by electrophilic trapping (with I2), provided a convenient preparative method for 1,2- or 1,2,3-multisubstituted aromatic compounds. The functionalized aromatic aluminate intermediate also was found to undergo copper- and palladium-catalyzed C-C bond-forming reactions very efficiently and highly regio- and chemoselectively. Copyright
- Uchiyama, Masanobu,Naka, Hiroshi,Matsumoto, Yotaro,Ohwada, Tomohiko
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p. 10526 - 10527
(2007/10/03)
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- Formation of 3-halobenzyne: Solvent effects and cycloaddition adducts
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Noncoordinating solvents permit the halogen-metal exchange-induced formation of benzyne (aryne) from di- and trihalobenzene precursors in the presence of cyclopentadiene to give 1,4-dihydro-1,4-methano-naphthalenes. Studies with mixed halide precursors and nonacidic Diels-Alder diene traps reveal that ethereal and hydrocarbon solvents influence the halide leaving group facility, resulting in a reversal of 3-halobenzyne regioselectivity.
- Coe, Jotham W.,Wirtz, Michael C.,Bashore, Crystal G.,Candler, John
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p. 1589 - 1592
(2007/10/03)
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- 1-Aryl-3,3-dialkyltriazenes: A convenient synthesis from dry arenediazonium o-benzenedisulfonimides - A high yield break down to the starting dry salts and efficient conversions to aryl iodides, bromides and chlorides
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This research comprises three parts. The first part regards the synthesis of 1-aryl-3,3-dialkyltriazenes 3 by reaction of dry arenediazonium o-benzenedisulfonimides 1, also coming from weakly basic aromatic amines with dimethylamine or diethylamine in aqueous solution at 0-5 °C. Yields were usually greater than 90% and there was the possibility of recovering the o-benzenedisulfonimide (5), which could be reused to prepare the salts 1. In the second part it was demonstrated that there is the possibility of reconverting the triazenes 3 into the starting stable dry salts 1 by using 5 as acid. The reactions were carried out in glacial acetic acid at 50-55 °C and normally afforded salts 1 in yields of around 90-99%. The third part concerns the setting up of two procedures for the conversion of 3 to aryl iodides 9, bromides 10 and chlorides 11. Procedure A used the corresponding aqueous hydrogen halides in acetonitrile at r.t. or 60 °C, sometimes in the presence of aqueous HBF4, sometimes Cu powder (25 examples, yields 65%-88%). Procedure B usually used anhydrous methanesulfonic acid and tetraalkylammonium halides in anhydrous acetonitrile at temperatures varying from r.t. to 80 °C, sometimes in the presence of Cu (16 examples, yields 65-88%).
- Barbero,Degani,Diulgheroff,Dughera,Fochi
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p. 2180 - 2190
(2007/10/03)
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- Two efficient routes to m-terphenyls from 1,3-dichlorobenzenes
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In the first route 2,6-dichlorophenyllithium (5), prepared by direct lithiation of 1,3-dichlorobenzene, reacted with aryl Grignard reagents to give m-terphenyls in 57-93% yields; the methodology was extended to substituted 1,3-dichlorobenzenes (i.e. 8 → 10). Also, reaction of 5 with MgCl2 gave 2,6-dichlorophenyl-magnesium chloride which, on warming, produced the self-capture product tetrachloro-m-terphenyl 7 in moderate yield. In the second route, reaction of 1,3-dichlorobenzene with excess of aryllithium in diethyl ether at room temperature gave the corresponding m-terphenyls in 59-94% yields. Examples are given in which the aryllithium was prepared by three different routes (ArX + Li, ArX + t-BuLi, ArH + BuLi).
- Saednya, Akbar,Hart, Harold
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p. 1455 - 1458
(2007/10/03)
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Functionalisation in 2 position of benzenes 1,3-disubstituted by para-directing groups has been investigated, involving 2-trimethylsilylated intermediates when the classical methods (particularly these involving the anion in 2 position) are ineffective. Thus 2-trimethylsilyl derivatives of 1,3-dihalo- or 1,3-dimethoxybenzene have been prepared in good yields. Their conversion into the corresponding 1,2,3-trisubstituted benzenes has been conveniently performed upon acetylation, iodination or sulfonation, except in the case of the sulfonation of the 1,3-dimethoxylated compound in which the ipso effect of the silyl group is surpassed by the directing effect of the methoxy substituents. In contrast, whith the same substrate, cyanation in position 2 was successfully carried out using chlorosulfonyl isocyanate: to our knowledge this reaction is the first example of substitution of a trimethylsilyl by a cyano group in the aromatic series.
- Bennetau, Bernard,Rajarison, Florent,Dunogues, Jacques,Babin, Pierre
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p. 10843 - 10854
(2007/10/02)
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- Nucleophilic Displacement in Polyhalogenoaromatic Compounds. Part 11. Kinetics of Protiodeiodination of Iodoarenes in Dimethyl Sulphoxide-Methanol
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The rates of methoxide-ion induced protiodeiodination of a number of polychloroiodobenzenes and their derivatives have been measured in dimethyl sulphoxide-methanol (9:1 v/v; 323.2 K).The true reagent under these conditions appears to be the dimethyl sulphoxide anion, and the rates of reaction in some cases appear to approach that expected of a diffusion controlled process.This corresponds to a major decrease in the efficacy of further activating substituents in the aromatic system, altough deactivating groups such as p-OMe still show large effects.Chlorine promotes protiodeiodination in the order of efficiency o-Cl > m-Cl > p-Cl; the trifluoromethyl group activates displacement in the order o-CF3 > p-CF3 > m-CF3, although with much less difference between isomeric sites. o-Nitro-groups promote protiodeiodination whereas the p-nitro-group encourages methoxydeiodination.No evidence of methoxydeiodination was found in attack of the polychloroiodobenzenes, although the rates of methoxydechlorination of the corresponding polychlorobenzenes suggest that in some cases this might occur.Evidence rejecting the possible SRN1 mechanism and supporting nucleophilic attack by a carbanionic species upon iodine is presented.
- Bolton, Roger,Moore, Clive,Sandall, John P.B.
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p. 1593 - 1598
(2007/10/02)
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