- Direct alkenylation of alkylazaarenes with aldehydes through C(sp3)-H functionalization under catalytic InCl3 activation
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Under the influence of InCl3 as a Lewis acid catalyst, a methodology on the C(sp3)-H functionalization of alkylazaarenes has been demonstrated through the activation of benzylic C-H bonds towards their addition reaction with the appropriate electrophiles. This methodology was chiefly applied in the direct alkenylation of primary and secondary benzylic C-H bonds of alkylazaarenes with aldehydes. A variety of alkenyl products were afforded in generally good yields including the starting alkenyl intermediate used in the synthesis of montelukast and other related molecules.
- Jamal, Zaini,Teo, Yong-Chua,Lim, Gina Shiyun
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p. 2132 - 2138
(2016/04/19)
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- C(sp3)-H functionalization of methyl azaarenes: a calcium-catalyzed facile synthesis of (E)-2-styryl azaarenes and 2-aryl-1,3-bisazaarenes
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Alkaline earth (Ca2+) catalyzed sp3 C-H functionalization of methyl azaarenes for the synthesis of biologically important (E)-2-styryl azaarenes, 2-aryl-1,3-bisazaarenes and 3,3-bisazaarenyl indolinones has been described. Initially methyl azaarenes react with aryl aldehydes to give β-hydroxy derivatives, which undergo Ca(II) catalyzed thermodynamic elimination to give the styryl azaarenes in a single step. Similarly it may undergo SN1 reaction to give 2-aryl-1,3-bisazaarenes and 3,3-bisazaarenyl indolinones (if isatin used as the electrophile). This green synthetic methodology enjoys the simple reaction procedures, solvent free conditions, step economy, substrate diversity and high yields of the products in short time.
- Yaragorla, Srinivasarao,Singh, Garima,Dada, Ravikrishna
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supporting information
p. 5924 - 5929
(2015/11/02)
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- Lewis-acid-catalyzed benzylic reactions of 2-methylazaarenes with aldehydes
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Lewis-acid-catalyzed benzylic reactions of 2-methylazaarenes with aldehydes have been investigated. Series of azaarene derivatives were afforded by this reaction. 2-(Pyridin-2-yl)ethanols with common substituents were formed through the LiNTf2-promoted aldol reaction for the first time. 2-Alkenylpyridines, exclusively in the form of the E isomers, were synthesized in the presence of LiNTf2 cooperated with H2NTf. In the presence of La(Pfb)3 as catalysis, 2-alkenylquinolines were obtained in high yields through the reactions between 2-methylquinolines and aldehydes under air.
- Mao, Dan,Hong, Gang,Wu, Shengying,Liu, Xin,Yu, Jianjun,Wang, Limin
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p. 3009 - 3019
(2014/05/20)
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- Iron-catalyzed C(sp3)-H functionalization of methyl azaarenes: A green approach to azaarene-substituted α- Or β-hydroxy carboxylic derivatives and 2-alkenylazaarenes
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Bioactive azaarene-substituted lactic acids, β-hydroxy esters, 3-hydroxy-2H-indol-2-ones, and 2-alkenylazaarenes were prepared in moderate-to-excellent yields via C(sp3)-H functionalization of methyl azaarenes with carbonyl compounds in the presence of iron(ii) acetate as an inexpensive, nontoxic, efficient catalyst. The application of this atom-, step-economic, and environmentally friendly method was demonstrated by a gram-scale synthesis of 3-[(E)-2-(7-chloroquinolin-2-yl)vinyl]benzaldehyde, a key intermediate of leukotriene receptor antagonist (Montelukast).
- Pi, Danwei,Jiang, Kun,Zhou, Haifeng,Sui, Yuebo,Uozumi, Yasuhiro,Zou, Kun
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p. 57875 - 57884
(2015/01/08)
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- Cobalt-catalyzed direct alkenylation of 2-methylquinolines with aldehydes via C(sp3)-H functionalization in water
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The direct C(sp3)-H alkenylation of 2-methylquinolines with aldehydes as a simple methodology to afford 2-alkenylated quinolines is reported. In the presence of catalytic CoCl2 in water, the economically and ecologically sound transformation is proposed to proceed via the direct benzylic addition to the aldehyde followed by an elimination step to provide 2-alkenylated quinolines in good to excellent yield of up to 95%. Georg Thieme Verlag Stuttgart New York.
- Jamal, Zaini,Teo, Yong-Chua
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supporting information
p. 2049 - 2053
(2014/11/08)
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- Process for the Preparation of E-3-[2-(7-Chloro-2-Quinolinyl)Ethenyl]Benzaldehyde
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An improved, scalable, and environmentally friendly manufacturing procedure for the preparation of E-3-[2-(7-chloro-2-quinolinyl)ethenyl]benzaldehyde, which is a key early intermediate used in the preparation of montelukast sodium, and the compound prepared by such a process.
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Page/Page column 4-5
(2010/02/17)
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- AN IMPROVED PROCESS FOR THE PREPARATION OF MONTELUKAST SODIUM AND ITS INTERMEDIATES
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The present invention relates to a process for the preparation of montelukast sodium (formula 1) and formula 4. The invention concerns the coupling of thiol derivative, Methyl 1 - (mercaptomethyl)cyclopropane acetate with mesylate of formula 4 compound using alkyl substituted ammonium hydroxide base, alkali amides and purification of Montelukast acid by crystallization in suitable organic solvents. The invention further concerns to provide an improved process of montelukast intermediates having good yield and quality
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Page/Page column 5; 6; 9
(2010/06/20)
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- PREPARATION OF ETHYL-3'-[((7-CHLORO-2-QUINOLINYL)ETHENYL)PHENYL]-3-OXOPROPANOATE, A KEY INTERMEDIATE FOR MONTELUKAST SODIUM
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A process for preparing β- ketoester of formula (III) comprises; (a)condensing alkyl 3- formylbenzoate with 7-Chloroquinaldine to give alkyl 3-[((7-chloro-2-quinolinyl) ethenyl)] benzoate; and (b) reacting alkyl 3-[((7-chloro-2-quinolinyl) ethenyl)] benzoate with an alkyl ester in presence of metal hydride/metal alkoxides to obtain a compound β- ketoester of structural formula (Ill) or (a) condensing isophthalaldehyde with 7-Chloroquinaldine to give Ethyl 3-[((7-chloro-2- quinolinyl) ethenyl)] benzaldehyde (b) reacting Ethyl 3-[((7-chloro-2-quinolinyl) ethenyl)] benzaldehyde with an α-halo ester in presence of a metal catalyst to give Ethyl 3'-[((7-chloro- 2-quinolinyl) ethenyl)phenyl] -3 -hydroxy propanoate; and (c) treating Ethyl 3'-[((7-chloro-2- quinolinyl)ethenyl)phenyl]-3-hydroxy propanoate with Collins reagent in an organic solvent to obtain a compound β- ketoester of structural formula (III).
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Page/Page column 8-9
(2009/03/07)
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- PREPARATION OF MONTELUKAST AND ITS SALTS
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There is provided a process for the preparation of montelukast of the Formula (I).
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Page/Page column 25-26
(2008/12/05)
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- A PROCESS FOR SYNTHESIZING DIOL (VIII)-AN INTERMEDIATE OF MONTELUKAST SODIUM
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A process comprises preparing benzaldehyde of formula I in a conventional manner, reacting the said benzaldehyde I with Grignard reagent in water miscible etheral solvent to precipitate the alcohol of formula (II) by addition of ammonium salt and water followed by isolating the alcohol thus precipitated by any known methods and then oxidizing directly under "Swern's conditions" to get a ketone of formula m, enolizing the said ketone in presence of a mild base such as alkali metal alkoxide and then reacting it with dialkyl carbonate under conditions effective to yield a β- ketoester of formula IV, benzylating the said β-ketoester so obtained in the preceding step to form the benzoate of formula V in presence of mild inorganic base followed by decarboxylating the said benzoate to a mixture of a ketoester of formula VI and its corresponding acid of formula VIA in the presence of acidic conditions, alkylating the acid VIA present in the mixture in the preceding step to obtain ketoester of formula VI and purifying it if so desired, asymmetrically reducing the ketoester of formula VI, to a chiral alcohol of formula VII using (-) diisopinocamphenylchloroborane (-DIPC1) in presence of less than 4 times v/w aprotic solvent and optionally in presence of Lewis base with respect to the said ketoester of formula VI, treating the said chiral alcohol VII with cerium halo salt, and alkylmagnesium halide followed by isolating the title compound using hyflow supercel and ammonium chloride to get the intermediate diol of formula VIII. Atemately, the said alcohol to Heck coupling with methyl-2-iodobenzoate in presence of Lewis base, acetonitrile, and palladium acetate to yield ketoester (VI), which is converted to diol (VIII) as described herein above.
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Page/Page column 19-20
(2010/10/20)
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- Novel approaches towards the LTD4/E4 antagonist, LY290154
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Several novel approaches have been investigated for the synthesis of the LTD4/E4 antagonist LY290154. Significant improvements to the discovery route were first made by using an indoline nucleophile instead of an indolyl anion in the key substitution step. An alternative approach, introducing the 7-chloroquinoline moiety in the latest stages of the synthesis was then demonstrated. Interestingly, the pivotal intermediate of this latter route was also obtained in a one-pot process following a Katritzky methodology. Finally, an asymmetric synthesis offering significant advantages over the enantioselective route reported by McKillop was demonstrated.
- Merschaert, Alain,Boquel, Pascal,Van Hoeck, Jean-Pierre,Gorissen, Hugo,Borghese, Alfio,Bonnier, Benjamin,Mockel, Anne,Napora, Freddy
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p. 776 - 783
(2012/12/22)
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- Synthesis of Montelukast (MK-0476) metabolic oxidation products
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We report the chemical synthesis of six oxidized derivatives of MK-0476 (Montelukast, L-706631), which have been key tools in the identification of its metabolites. We have prepared three diastereoisomeric pairs of potential oxidative metabolites of MK-0476, starting from the (S)-hydroxy ester 7 in 10 and five steps, and starting from MK-0476 itself in one step. The key benzylic hydroxyl of 1 and 2 was introduced by a bromination and saponification reaction sequence. In the case of the hydroxyl of 3 and 4, the key step was the addition of a hydroxymethyl carbanion equivalent on ketone 20. The two sulfoxide 5 and 6 were prepared by a direct oxidation of MK-0476 with m-chloroperbenzoic acid.
- Dufresne, Claude,Gallant, Michel,Gareau, Yves,Ruel, Rejean,Trimble, Laird,Labelle, Marc
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p. 8518 - 8525
(2007/10/03)
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- AZABENZIMIDAZOLES IN THE TREATMENT OF ASTHMA, ARTHRITIS AND RELATED DISEASES
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A series of imidazo[4,5-c]pyridines which inhibit platelet activating factor (PAF) and also block leukotriene D4 receptors are useful in treating asthma, arthritis, psoriasis, gastrointestinal distress, myocardial infarction, stroke and shock.
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- Development of a novel series of styrylquinoline compounds as high- affinity leukotriene D4 receptor antagonists: Synthetic and structure- activity studies leading to the discovery of (±)-3-[[[3-[2-(7-chloro-2- quinolinyl)-(E)-ethenyl]phenyl][[3-(dimethylamino)-3- oxopropyl]thio]methyl]thio]propionic acid
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Based on LTD4 receptor antagonist activity of 3-(2-quinolinyl-(E)- ethenyl)pyridine (2) found in broad screening, structure-activity studies were carried out which led to the identification of 3-[[[3-[2-(7-chloro-2- quinolinyl)-(E)-ethenyl]phenyl][[3-(dimethylamino)-3- oxopropyl]thio]methyl]thio]propionic acid (1, MK-571) as a potent and orally active LTD4 receptor antagonist. These studies demonstrated that a phenyl ring could replace the pyridine in 2 without loss of activity, that 7-halogen substitution in the quinoline group was optimal for binding, that the (E)- ethenyl linkage was optimal, that binding was enhanced by incorporation of a polar acidic group or groups in the 3-position of the aryl ring, and that two acidic groups could be incorporated via a dithioacetal formed from thiopropionic acid and the corresponding styrylquinoline 3-aldehyde to yield compounds such as 20 (IC50 = 3 nM vs [3H]LTD4 binding to the guinea pig lung membrane). It was found that one of the acidic groups could be transformed into a variety of the amides without loss of potency and that the dimethylamide 1 embodied the optimal properties of intrinsic potency (IC50 = 0.8 nM on guinea pig lung LTD4 receptor) and oral in vivo potency in the guinea pig, hyperreactive rat, and squirrel monkey. The evolution of 2 to 1 involves the increase of >6000-fold in competition for [3H]LTD4 binding to guinea pig lung membrane and a >40-fold increase in oral activity as measured by inhibition of antigen-induced dyspnea in hyperreactive rats.
- Zamboni,Belley,Champion,Charette,DeHaven,Frenette,Gauthier,Jones,Leger,Masson,McFarlane,Metters,Pong,Piechuta,Rokach,Therien,Williams,Young
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p. 3832 - 3844
(2007/10/02)
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- Synthesis of Unsymmetrical Dithioacetals: An Efficient Synthesis of a Novel LTD4 Antagonist, L-660,711
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An efficient four-step synthesis of the potent LTD4 antagonist L-660,711 (1) is described.The key step involves selective conversion of aldehyde 2 to the unsymmetrical dithioacetal 7, via O-trimethylsilyl hemithioacetal 10.This specific cleavage of the carbon-oxygen bond of a mixed O,S-acetal permits the unprecedented synthesis of unsymmetrical dithioacetals.
- McNamara, J. M.,Leazer, J. L.,Bhupathy, M.,Amato, J. S.,Reamer, R. A.,et al.
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p. 3718 - 3721
(2007/10/02)
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- 2-substituted quinoline dioic acids and pharmaceutical compositions
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Compounds having the formula: STR1 are antagonists of leukotrienes and inhibitors of their biosynthesis. These compounds are useful as anti-asthmatic, anti-allergic, anti-inflammatory, and cytoprotective agents.
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- 2-Substituted quinoline dioic acids
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Compounds having the formula: are antagonists of leukotrienes and inhibitors of their biosynthesis. These compounds are useful as anti-asthmatic, anti-allergic, anti-inflammatory, and cytoprotective agents.
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