- Preparation method of escitalopram process impurity
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The invention relates to a preparation method of an escitalopram process impurity. The escitalopram process impurity is prepared through a reaction of 5-cyanophthalide and 4-fluorophenyl magnesium bromide. The process is simple and the yield is relatively high.
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Paragraph 0005; 0012-0014
(2019/01/08)
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- Process development of citalopram/Escitalopram oxalate: Isolation and synthesis of novel impurities
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During process optimization of Escitalopram oxalate novel impurities, 6 and 7 were observed, which were isolated and characterized, and the proposed structure was confirmed by chemical synthesis. Investigation of the cause of impurities formation improved
- Pramanik, Chinmoy,Hivarekar, Raghvendra R.,Deshmukh, Sanjay S.,Tripathy, Narendra K.,Kotharkar, Sandeep,Chaudhari, Ashok,Gurjar, Mukund K.
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experimental part
p. 824 - 829
(2012/08/27)
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- CARBONYL ASYMMETRIC ALKYLATION
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This invention relates to processes and intermediates for the stereoselective alkylation of carbonyl groups. The invention in particular allows the stereoselective preparation of the antidepressant drug escitalopram. It has been found that boric or boronic acid derivatives are useful bridging elements for the attachment of a chiral group to a compound containing a carbonyl group to be alkylated. The said borates and boronates are thus useful in a process for the asymmetric alkylation of a carbonyl group in a compound containing a carbonyl group and an anchor group capable of reacting with a boric or boronic acid derivative. The asymmetric alkylation can be carried out by admixing the compound containing a carbonyl group to be alkylated and the anchor group capable of reacting with a boric or boronic acid derivative with a boric or boronic acid derivative, adding a chiral alcohol, and adding an organometallic compound. After the alkylation reaction, the borate and boronate can be easily removed by hydrolysis.
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Page/Page column 22
(2010/11/28)
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- PROCESS FOR PREPARING 5-SUBSTITUTED -1-(4-FLUOROPHENYL) -1,3-DIHYDROISOBENZOFURANS
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The present invention relates to a method for preparation and isolation of hitherto unknown solid boron complex of formula (v), which are obtained when 5-substituted phthalides are reacted with a solution of 4-fluorophenylmagnesiumbromide, followed by in situ reduction and complex formation in the presence of sodiumborohydride. Such boron complexes can be conveniently filtered to remove structurally similar impurities and subsequently subjected to cyclisation reaction in acidic medium to get high pure 5-substituted phthalens, which are key starting materials for manufacturing citalopram and pharmaceutically acceptable acid addition salts.
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Page/Page column 9
(2008/06/13)
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- ONE POT SYNTHESIS OF CITALOPRAM FROM 5-CYANOPHTHALIDE
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A process for one pot synthesis of citalopram is disclosed. The process comprises subjecting 5-cyano phthalide to Grignard reduction followed cyclization and followed by C-alkylation reaction to obtain citalopram without isolation and purification of any intermediates. In another embodiment, 5-cyano phthalide is subjected to sequential Grignard reactions followed by cyclization to obtain citalopram without isolation and purification of any intermediate stages.
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Page/Page column 8-9; 10-11
(2008/06/13)
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- PROCESS FOR THE PREPARATION OF A CYANO-ISOBENZOFURAN
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A process for the preparation of citalopram and the pharmaceutically acceptable salts therof is disclosed by reacting 5-cyanophthalide with a 4-fluorophenyl magnesium halide, reducing the 3-hydroxymethyl-4-(4-fluoro-benzoyl)benzonitrile with an agent reducing ketones to alcohols, submitting the thus-obtained 3-hydroxymethyl-4- [(4-fluorophenyl)hydroxymethyl) benzonitrile to a cyclization reaction to give 1-(4-fluorophenyl)-1,3-dihydro-5-isobenzofurancarbonitrile without 1,1-bis(4-fluorophenyl)-1,3-dihydro-5- isobenzofurancarbonitrile and treating 1,1-bis(4 fluorophenyl)-1,3-dihydro-5- isobenzofurancarbonitrile with a 3-(dimetylamino)propyl halide in the presence of a base.
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Page 17-18; 13; 7; 20-21
(2008/06/13)
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- Method for the preparation of citalopram
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A method for the preparation of citalopram comprising reaction of a compound of Formula (IV), wherein R is C1-6 alkyl, acyl, C1-6 alkylsulfonyl or arylsulfonyl, with 3-(N,N-dimethylamino)propyl magnesium halide, to prepare citalopram.
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