- Impact of Oxidation State on Reactivity and Selectivity Differences between Nickel(III) and Nickel(IV) Alkyl Complexes
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Described is a systematic comparison of factors impacting the relative rates and selectivities of C(sp3)?C and C(sp3)?O bond-forming reactions at high-valent Ni as a function of oxidation state. Two Ni complexes are compared: a catio
- Roberts, Courtney C.,Camasso, Nicole M.,Bowes, Eric G.,Sanford, Melanie S.
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- Regio-selective synthesis of key intermediates of fexofenadine
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The present work is focused on improved process of preparation of fexofenadine which is achieved by regio-selective synthesis of intermediate; 1-oxoalkoxy-2-methyl-2-[4-(4-chloro-1-oxobutyl)phenyl]propane. The said intermediate is prepared in good yields and with greater purity wherein the synthesis of side products like 1-oxoalkoxy-2-methyl-2-[3-(4-chloro-1-oxobutyl)phenyl]propane (metaisomer) is reduced to a great amount. The intermediate, 1-oxoalkoxy-2-methyl-2-[4-(4-chloro-1-oxobutyl)phenyl]propane (para-isomer) where, alkyl group is selected from C2-5 carbon chain, is synthesized through preparation of 1-chloro-2-methyl-2-phenylpropane which upon reaction with potassium salt of aliphatic carboxylic acid followed by Friedel-Crafts acylation with 4-chlorobutyrylchloride results into desired intermediate, 1-oxoalkoxy-2-methyl-2-[4-(4-chloro-1-oxobutyl)phenyl]propane and a side impurity, 1-oxoalkoxy-2-methyl-2-[3-(4-chloro-1-oxobutyl)phenyl]propane (meta-isomer) in the ratio of 1:0.09-0.15. The above said mixture can be directly used for the synthesis of fexofenadine and has an advantage of eliminating the purification process at intermediate stage and use of less volume of expensive solvents.
- Kumar, Anil,Bhashkar, Bhuwan,Kumar, Harish,Singh, Gurpreet
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p. 2285 - 2287
(2015/12/19)
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- The synthesis of fexofenadine
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This work proposes a new simple route for fexofenadine synthesis with low cost and easily obtainable raw materials. We use benzene and methallyl as starting reactants, applying steps of Friedel-Crafts alkylation reaction, hydrolysis, oxidation, esterification reaction, and reduction reaction to obtain the intermediate product, followed by N-alkylation reaction to obtain 4-{1-hydroxy-4-[4-(hydroxydiphenyl)-piperidine]butyl}-α, α-dimethylbenzene acetate. Then, the final product fexofenadine is obtained upon hydrolysis. In the synthesis process, we constantly optimize the reaction conditions such as reaction time, reaction temperature, solvent selection, and other factors, thus improving the final yield of the target product fexofenadine to 33.51 %.
- Ronggeng, Wang,Yougui, Zhao,Guanchao, Zhang
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p. 2149 - 2155
(2013/06/05)
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- Synthesis of [2H5]-ebastine fumarate and [ 2H5]-hydroxyebastine
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This study describes the synthesis of deuterium-labelled ebastine fumarate and its deuterium-labelled metabolite hydroxyebastine. The synthesis of the two desired compounds both used [2H5]-bromodiphenylmethane as deuterium-labelled reagent, which was synthesized beforehand in three steps. [2H5]-ebastine was synthesized in further three steps with a 27% overall yield and [2H5]-hydroxyebastine was synthesized in further seven steps with a 13% overall yield.
- Yu, Zhoujie,Wang, Wei,Chen, Liqin
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experimental part
p. 352 - 356
(2012/06/01)
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- A process for producing 4-(4-halo-1-oxybutyl)-alpha,alpha-dimethylbenzene acetic acid or alkyl esters thereof
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Disclosed herein is a process for large scale production of pure 4-(4-halo-1-oxybutyl)-α,α-dimethylbenzene acetic acid or alkyl esters thereof, wherein the process comprises of condensing (2-halo-1,1-dimethyl-ethyl)benzene with acetate salt followed by acylation with ω-halo compound, hydrolyzing and cyclizing the resultant regioisomers, subsequently oxidizing and purifying to obtain pure regioisomer, further halogenating and/or esterifying the para regioisomer to produce 4-(4-halo-1-oxybutyl)-α,α-dimethylbenzene acetic acid or their alkyl esters.
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Page/Page column 7
(2011/04/14)
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- ARYL SULFONAMIDES
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Compounds are provided that act as potent antagonists of the CCR9 receptor, and which have been further confirmed in animal testing for inflammation, one of the hallmark disease states for CCR9. The compounds are generally aryl sulfonamide derivatives and are useful in pharmaceutical compositions, methods for the treatment of CCR9-mediated diseases, and as controls in assays for the identification of CCR9 antagonists.
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- Intermediates useful for the preparation of antihistaminic piperidine derivatives
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The present invention is related to a novel intermediates and processes which are useful in the preparation of certain antihistaminic piperidine derivatives of the formula whereinW represents —C(=O)— or —CH(OH)—;R1 represents hydrogen or hydroxy;R2 represents hydrogen;R1 and R2 taken together form a second bond between the carbon atoms bearing R1 and R2;n is an integer of from 1 to 5;m is an integer 0 or 1;R3 is —COOH or —COOalkyl wherein the alkyl moiety has from 1 to 6 carbon atoms and is straight or branched each of A is hydrogen or hydroxy; andpharmaceutically acceptable salts and individual optical isomers thereof, with the proviso that where R1 and R2 are taken together to form a second bond between the carbon atoms bearing R1 and R2 or where R1 represented hydroxy, m is an integer 0.
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Page column 87
(2008/06/13)
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- Intermediates useful for the preparation of antihistaminic piperidine derivatives
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The present invention is related to a novel intermediates and processes which are useful in the preparation of certain antihistaminic piperidine derivatives of the formula whereinW represents —C(=O)— or —CH(OH)—;R1 represents hydrogen or hydroxy;R2 represents hydrogen;R1 and R2 taken together form a second bond between the carbon atoms bearing R1 and R2;n is an integer of from 1 to 5;m is an integer 0 or 1;R3 is —COOH or —COOalkyl wherein the alkyl moiety has from 1 to 6 carbon atoms and is straight or branched each of A is hydrogen or hydroxy; and pharmaceutically acceptable salts and individual optical isomers thereof,with the proviso that where R1 and R2 are taken together to form a second bond between the carbon atoms bearing R1 and R2 or where R1 represented hydroxy, m is an integer 0.
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Page column 87
(2010/01/30)
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- A new synthesis of carboxyterfenadine (fexofenadine) and its bioisosteric tetrazole analogs
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A new synthesis of carboxyterfenadine (4), based on the conversion of a α-halo-alkylarylketone into the corresponding substituted 2-arylalkanoic ester, is described. The enantioselective synthesis of its two bioisosteric tetrazole analogs together with preliminary biological results are reported. Copyright (C) 1999 Elsevier Science S.A.
- Di Giacomo, Barbara,Coletta, Donato,Natalini, Benedetto,Ni, Ming-Hong,Pellicciari, Roberto
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p. 600 - 610
(2007/10/03)
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