- Triphosgene and DMAP as Mild Reagents for Chemoselective Dehydration of Tertiary Alcohols
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The utility of triphosgene and DMAP as mild reagents for chemoselective dehydration of tertiary alcohols is reported. Performed in dichloromethane at room temperature, this reaction is readily tolerated by a broad scope of substrates, yielding alkenes preferentially with the (E)-geometry. While formation of the Hofmann products is generally favored, a dramatic change in alkene selectivity toward the Zaitzev products is observed when the reaction is carried out in dichloroethane at reflux.
- Ganiu, Moshood O.,Cleveland, Alexander H.,Paul, Jarrod L.,Kartika, Rendy
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supporting information
p. 5611 - 5615
(2019/08/01)
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- Menglusitena a high yield new method for the synthesis of (by machine translation)
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The invention discloses a method for preparing Menglusitena, the method adopts a one-pot synthesis, in order to 2 - (2 - (3 - (2 - (7-chloro-2-quinolyl) vinyl) phenyl) - 3-oxo-propyl) phenyl) propyl alcohol as the starting material, and 1 - (thiomethyl)-c
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- Preparation method of montelukast sodium intermediates
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The invention relates to a preparation method of montelukast sodium intermediates. The method comprises the steps that under the protection of inert gas, in solvent, nucleophilic substitution is conducted on a montelukast mother nucleus compound, replaced by various leaving groups, of secondary hydroxyl and various side chains respectively under the action of a catalyst, and various montelukast sodium intermediates are obtained. According to the preparation method of the montelukast sodium intermediates, new catalysts of 4-dimethylaminopyridine and 4-pyrrolidinopyridine are utilized, the reaction is mild in condition and rapid, the product is single, purification is easy and convenient, the obtained intermediates are high in optical purity and higher in yield, and the preparation method is more suitable for industrial production.
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Paragraph 0034; 0035; 0036
(2016/12/26)
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- METHOD FOR PRODUCING MONTELUKAST ALKYL ESTER
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PROBLEM TO BE SOLVED: To provide a method for efficiently producing a high purity 1-(((1(R)-(3-(2-(7-chloro-2-quinonyl)ethenyl)phenyl)-3-(2-(1-hydroxy-1-methylethyl)phenyl)propyl)thio)methyl)cyclopropane acetic acid alkyl ester having a reduced content of a specific impurity. SOLUTION: A specific amount of a weakly basic nitrogen-containing organic compound is made to exist in a reaction system in a reaction between 2(2-(3(S)-(3-(2-(7-chloro-2-quinonyl)ethenyl)phenyl)-3-methanesulfonyloxypropyl)phenyl)-2-propanol and 1-mercaptomethylcyclopropane acetic acid alkyl ester in the presence of a strong base. COPYRIGHT: (C)2015,JPO&INPIT
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- MONTELUKAST INTERMEDIATE CAMPHORSULFONIC SALT
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The present invention is directed to a novel salt of a montelukast intermediate, the process of preparation thereof, the use of such salt in the preparation of sodium montelukast and a process for the preparation of sodium montelukast making use of said salt.
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Page/Page column 22-23
(2012/10/07)
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- Identification, synthesis and characterization of impurities of Montelukast sodium
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Montelukast sodium is a selective leukotriene receptor antagonist which inhibits cysteinyl leukotriene CysLT1 receptor. Various synthesis of Montelukast is published. During laboratory optimization and later in bulk synthesis formation of various impurities was detected. Besides, pharma Europa draft mention nine process related impurities. However, the method of preparation of most of these impurities is not available in literature. Also, different route of synthesis will have different impurity profile and those process related impurities are not covered in pharmacopeias. In this study we report the synthesis of possible process impurities, including seven impurities (A-H) mentioned in pharma Europa.
- Sunil Kumar,Anjaneyulu,Hima Bindu
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p. 4536 - 4546
(2012/02/04)
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- EFFICIENT SYNTHESIS FOR THE PREPARATION OF MONTELUKAST AND NOVEL CRYSTALLINE FORM OF INTERMEDIATES THEREIN
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The present invention describes the improved process for the preparation of montelukast acid (VII) and its pharmaceutically acceptable salts and esters using a novel synthesis step. The process is cost effective, environment friendly, and easily scale up to commercial level and leads to products having high chemical and optical purity. Moreover, the present invention provides a novel crystalline intermediate (IV) that is useful in this process and a method for its production. In a further aspect, the process of the present invention includes a step of removing ketone by-products be derivatization.
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Page/Page column 32; 33
(2011/10/13)
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- Efficient synthesis for the preparation of montelukast
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The present invention describes the improved process for the preparation of montelukast acid and its pharmaceutically acceptable salts and esters. The process is cost effective, environment friendly, and easily scale up to commercial level.
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Page/Page column 9-10
(2011/04/14)
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- METHOD FOR PREPARATION OF MONTELUKAST ACID IN IONIC LIQUID MEDIUM
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The present invention relates to a method for preparing Montelukast acid or its sodium salt by reacting a thiol compound with a Montelukast intermediate in the presence of a base in a medium comprising an ionic liquid compound. In accordance with the inventive method, highly pure Montelukast acid or its sodium salt, which is advantageously used as a raw material in the preparation of Montelukast, a leukotriene antagonist, can be easily prepared in a high yield.
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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; 8; 15
(2010/06/20)
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- Process for the Preparation of Montelukast and Its Pharmaceutically Acceptable Salts
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An improved process for the preparation of Montelukast and its pharmaceutically acceptable salts comprises of reacting (S) Benzenepropanol α-[3-[2-(7-chloro2-quinolinyl)ethenyl]phenyl]-2-(1-hydroxy-1-methyl ethyl)-α-methane sulfonate compound of formula (II) with 1-(mercapto methyl)cyclo propane acetic acid or its ester or nitrile in presence of alkali or alkaline carbonates and/or alkali or alkaline earth metal alkoxide in a suitable polar aprotic solvent with or without combination of C1-C4 alcoholic solvents and then treating with organic amine in a suitable ester and/or acetone and/or aliphatic or aromatic hydrocarbon solvents, and converting the corresponding amine salt compound of montelukast into its sodium salt compound of formula (I) using sodium ion source in methanol, without converting into montelukast free acid.
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Page/Page column 8
(2009/07/17)
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- Process for the Preparation of Leukotriene Receptor Antagonist (Montelukast Sodium)
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The present invention relates to an improved process for the preparation of [R-(E)]-1-[[[1-[3-[2-(7-chloroquinolin-2-yl)ethenyl]phenyl]-3-[2-(1-hydroxy-1-methylethyl)phenyl]propyl]thio]methyl]-cyclopropaneacetic acid, monosodium salt of Formula (I).
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Page/Page column 6-7
(2010/01/31)
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- A PROCESS FOR PREPARATION OF MONTELUKAST SODIUM SALT
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The present invention relates to a process for the preparation of montelukast sodium salt. The process includes (a) reacting 2-(2-(3-(S)-(3-(7-chloro-2- quinolinyl)-ethenyl) phenyl)-3-hydroxypropyl)- phenyl-2-propanol of Formula (II) with diphenyl chloro phosphate to get a compound of Formula III; (b) condensing the compound of Formula III with a compound of Formula IV to get compound of Formula V; (c) and converting the compound of Formula V to montelukast sodium of Formula (I).
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Page/Page column 14-15
(2009/12/23)
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- METHOD OF PREPARING MONTELUKAST AND INTERMEDIATES USED THEREIN
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The present invention relates to a method for preparing montelukast, an inhibitor against leukotrienes, and an intermediate used therein. According to the inventive method, high-purity montelukast or its sodium salt can be prepared in a high yield.
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Page/Page column 9-10
(2008/12/06)
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- AN IMPROVED PROCESS FOR THE PREPARATION OF LEUKOTRIENE RECEPTOR ANTAGONIST (MONTELUKAST SODIUM)
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The present invention relates to an improved process for the preparation of [R-(E)]-1-[[[1-[3-[2-(7-chloroquinolin-2-yl)ethenyl]phenyl]-3-[2-(1-hydroxy-1-methylethyl)phenyl]propyl]thio]methyl]-cyclopropaneacetic acid, monosodium salt of Formula (I).
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Page/Page column 13
(2010/11/29)
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- AN IMPROVED PROCESS FOR THE PREPARATION OF MONTELUKAST AND ITS PHARMACEUTICALLY ACCEPTABLE SALTS
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An improved process for the preparation of Mσntelukast and its pharmaceutically acceptable salts comprises of reacting (S) Benzenepropanol α -[3-[2-(7-chloro2-quinolinyl) ethenyl]phenyl]-2-(l-hydroxy-1-methyl ethyl)-α-methane sulfonate compound of formula (II) with l-(mercapto methyl) cyclo propane acetic acid or its ester or nitrile in presence of alkali or alkaline carbonates and/or alkali or alkaline earth metal alkoxide in a suitable polar aprotic solvent with or without combination of C1-C4 alcoholic solvents and then treating with organic amine in a suitable ester and/or acetone and/or aliphatic or aromatic hydrocarbon solvents, and converting the corresponding amine salt compound of montelukast into its sodium salt compound of formula (I) using sodium ion source in methanol, without converting into montelukast free acid.
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Page/Page column 11; 20
(2010/11/27)
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- PURIFICATION OF MONTELUKAST
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The present invention provides methods of purifying montelukast, a new isolated impurity of montelukast of formula I, method for its isolation, and method of using montelukast impurity as a reference marker and a reference standard.
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Page/Page column 18-19
(2010/11/25)
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