- Preparation method of levocetirizine
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The invention provides a preparation method of levocetirizine. The preparation method comprises following steps: carrying out a reaction on a compound represented by a formula (I) under the action ofa reduction system and L-tartaric acid to obtain a compound represented by a formula (II); and reacting the compound shown in a formula (II) with a compound shown in a formula (III) under the action of NaH, N,N-dimethyl formamide and tetrabutyl ammonium bromide to obtain levocetirizine. The levocetirizine is prepared by taking the compound shown by the formula (I) and the compound shown by the formula (III) as raw materials, at first, the compound shown by the formula (I) is de-protected and then racemized to obtain the compound shown by the formula (II); and the compound shown by the formula(II) and the compound shown by the formula (III) carry out reactions to obtain levocetirizine. The provided method is short in reaction route, the yield can reach 54% or above, and the purity can reach 99.65% at most.
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Paragraph 0024; 0027
(2020/06/17)
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- AN IMPROVED PROCESS FOR THE PREPARATION OF ANTIHISTAMINIC DRUGS VIA A NOVEL CARBAMATE INTERMEDIATE
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The present invention relates to a novel racemic or optically active carbamate intermediate of formula (IV A). This novel racemic or optically active carbamate intermediate of formula (IV A) can be used to prepare drugs having antihistaminic activity such as cetirizine (IA), meclizine (IB), chlorcyclizine (IC), clocinizine (ID), buclizine (IE) and enantiomers thereof such as levocetirizine (I). Further, disclosed herein is an improved process for the preparation of levocetirizine via a novel optically active intermediate i.e. compound of formula (IV). Also, disclosed herein is a novel process for the preparation of compound (II) and for crystallization of its salt.
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Page/Page column 14
(2012/08/08)
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- PROCESS FOR MAKING N-(DIPHENYLMETHYL)PIPERAZINES
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A compound of formula (8) or a salt thereof: wherein Z represents a group containing 1-20 carbon atoms and at least one chiral carbon atom and having a single conformation, is useful in the synthesis of pharmaceutical compounds, especially chiral compounds such as levocetirizine.
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Page/Page column 8-9
(2010/06/19)
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- LEVOCETIRIZINE BY MENTHYL INTERMEDIATE
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The invention relates to a process for making levocetirizine, to a process for converting the racemic compound (4) into enantiomers, and to compounds used thereby.
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Page/Page column 22-23
(2010/07/10)
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- PROCESS FOR PREPARATION OF SUBSTANTIALLY OPTICALLY PURE LEVOROTATORY AND DEXTROROTATORY ENANTIOMERS OF CETIRIZINE USING NOVEL INTERMEDIATES
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The present invention relates to a novel and commercially viable process for substantially optically pure levorotatory and dextrorotatory enantiomers of cetirizine intermediate, 1-[(4-chlorophenyl)phenylmethyl]piperazine, thereby producing substantially optically pure levorotatory and dextrorotatory enantiomers of cetirizine and their pharmaceutical acceptable acid addition salts thereof in high purity and in high yield using novel intermediates.
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Page/Page column 3
(2009/12/04)
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- METHOD FOR PREPARING (R)-(-)-1-[(4-CHLOROPHENYL)PHENYLMETHYL]PIPERAZINE
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The present invention relates to a novel method for preparing (R)-(-)-1-[(4-chlorophenyl)phenylmethyl]piperazine of formula (I), which is useful as an intermediate for preparing an antihistamine, levocetirizine.
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Page/Page column 8-9
(2009/07/18)
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- Process for making n-(diphenylmethyl)piperazines
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The compound of formula (8), in racemic or single enantiomeric form, is useful in making N-(diphenylmethyl)-piperazines such as cetirizine and levocetrizine. wherein Z is preferably phenyl.
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Page/Page column 8-9
(2009/06/27)
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- PROCESSES FOR PREPARING LEVOCETIRIZINE AND PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF
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Processes for preparing levocetirizine dihydrochloride.
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Page/Page column 21-22
(2009/06/27)
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- NEW PROCESS FOR THE PREPARATION OF LEVOCETIRIZINE AND INTERMEDIATES THEREOF
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The present invention describes a novel process for the preparation of levocetirizine and pharmaceutically acceptable acid addition salts thereof via a ketocetirizine ester and new ketocetirizine ester intermediates used in that process. reaction of ketocetirizine of the formula (IIIb) to a ketocetirizine ester of the formula (IV) or a salt thereof.
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Page/Page column 18
(2010/01/07)
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- NEW PROCESS FOR THE PREPARATION OF LEVOCETIRIZINE AND INTERMEDIATES THEREOF
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The present invention describes a novel process for the preparation of levocetirizine and pharmaceutically acceptable acid addition salts thereof using diglycolic acid or derivatives thereof and new intermediates used in that process.
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Page/Page column 11; 20
(2008/12/07)
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