6645-46-1Relevant articles and documents
NOVEL CRYSTALLINE FORMS
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Page/Page column 12; 13, (2017/12/01)
Preparation and characterization of novel forms of (1-hydroxy-2-imidazol-1-yl-1-phosphono-ethyl) phosphonic acid, suitable for pharmaceutical compositions in drug delivery systems for humans.
Asymmetric synthesis of l-carnitine from (R)-3-chloro-1,2-propanediol
Li, Xu Qin,Yang, Yun Xu,Wang, Wei Li,Hu, Bin,Xue, Hui Min,Zhang, Tian Yi,Zhang, Xue Tao
body text, p. 765 - 767 (2012/01/03)
A practical chemical synthesis of l-carnitine (1) has been accomplished from (R)-3-chloro-1,2-propanediol ((R)-4), which is a main by-product originated from (R,R)-Salen Co(III) catalyzed hydrolytic kinetic resolution (HKR) of (±)-epichlorohydrin. (R)-4 was utilized as a chiral starting material to prepare the key intermediate cyclic sulfite ((R)-5). The new synthetic approach demonstrated an efficient utilization of organic by-product for the asymmetric synthesis of bioactive compounds.
Practical and efficient utilisation of (R)-3-chloro-1,2-propanediol in synthesis of L-carnitine
Yang, Yunxu,Wang, Weili,Wumaier, Aikeremu,Sheng, Ruilong,Zhang, Xuetao,Zhang, Tianyi
scheme or table, p. 371 - 372 (2011/10/09)
As a by-product originating from Salen Co(III) catalysed hydrolytic kinetic resolution (HKR) of (±)-epichlorohydrin in the manufacturing procedure of L-Carnitine, (R)-3-chloro-1,2-propanediol was utilised as a starting chiral material to prepare via key nitrile intermediates and by a final hydrolysis L-Carnitine. The new synthetic approach demonstrated an efficient utilisation of the by-product.
Lipase-catalyzed enantiomer separation of 3-hydroxy-4-(tosyloxy) butanenitrile: Synthesis of (R)-GABOB (=(3R)-4-amino-3-hydroxybutanoic acid) and (R)-carnitine hydrochloride (= (2R)-3-carboxy-2-hydroxy-N,N,N-trimethylpropan- 1-aminium chloride)
Kamal, Ahmed,Khanna, G. B. Ramesh,Krishnaji, Tadiparthi
, p. 1723 - 1730 (2008/03/12)
Enzymatic resolution of racemic 3-hydroxy-4-(tosyloxy)butanenitrile ((±)-5) by using various lipases in different solvents were studied. The obtained optically pure (3R)-3-(acetyloxy)-4-(tosyloxy)-butanenitrile ((R)-6), upon treatment with aqueous ammonia followed by cone. HCl solution, provided (R)-GABOB (=(3R)-4-amino-3-hydroxybutanoic acid; (R)-1). Similarly, reaction of (R)-6 with aqueous trimethylamine solution followed by cone. HCl solution provided (R)-carnitine hydrochloride (=(2R)-3-carboxy-2-hydroxy-N,N,N- trimethylpropan-1-aminium chloride; (R)-2·HCl) in an expeditious manner.
PROCESS FOR L-CARNITINE AND ACETYL L-CARNITINE HYDROCHLORIDE
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Page/Page column 9-10, (2010/11/29)
Provided is a process for preparing L-carnitine or acetyl L-carnitine hydrochloride. Specifically, the process comprises sequentially synthesizing racemic 4-chloro-3-hydroxybutyronitrile and racemic 4-chloro-3-hydroxy butyric acid alkyl ester under specific reaction conditions, using racemic epichlorohydrin as a starting material, preparing (R)-4-chloro-3-hydroxy butyric acid alkyl ester from stereoselective hydrolysis of the racemic 4-chloro-3-hydroxy butyric acid alkyl ester using an enzyme, and preparing L-carnitine or acetyl L-carnitine hydrochloride from the (R)-4-chloro-3-hydroxy butyric acid alkyl ester, according to the known method.
Process for preparing optically active carnitine ester
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, (2008/06/13)
A process for preparing an optically active carnitine ester represented by formula (I): wherein R represents a lower alkyl group; and X represents a halogen atom, is disclosed, comprises asymmetrically hydrogenating a γ-trimethylammonium-3-oxobutanoic ester halide represented by formula (II): wherein R and X are as defined above, in the presence of a ruthenium-optically active phosphine complex as a catalyst. An optically active carnitine ester of any desired isomerism can be obtained through simple operation in high yield at high optical purity. The substrate used is easily available.
ENANTIOSELECTIVE HYDROGENATION REACTIONS WITH A FULL SET OF PREFORMED AND PREPARED IN SITU CHIRAL DIPHOSPHINE-RUTHENIUM (II) CATALYSTS
Genet, J. P.,Pinel, C.,Ratovelomanana-Vidal, V.,Mallart, S.,Pfister, X.,et al.
, p. 675 - 690 (2007/10/02)
The new class of 2-methylallyl ruthenium chiral diphosphines 1 are efficient in asymmetric hydrogenation of α,β unsaturated acids and allylic alcohols.The related chiral halogen-containing ruthenium catalysts 2 are prepared from 1 or in situ from (COD)Ru(η3-(CH2)2CHCH3)2 by ligand exchange with the chelating diphosphine followed by protonation (HX) in acetone.This procedure allows rapid screening of chiral phosphines, such as Diop, Chiraphos, Cbd, Bppm, Binap, β-glucophos, Biphemp, MeO-Biphep, Me-Duphos, in ruthenium mediated hydrogenations of prochiral substrates.A high efficiency is displayed by Ru-catalysts having atropisomeric ligands (e.e. up to 99percent), and a C2 symmetric bis(phospholane) has also emerged as a valuable ligand (Me-Duphos, e.e. up to 87percent not optimized).Asymmetric hydrogenation of β-keto esters can be conducted under quite mild conditions (4 atm. of H2, 50 deg C, e.e. up to 99percent), β-keto esters having a disubstituted double bond are also hydrogenated chemoselectively to unsaturated chiral alcohols under controlled conditions with excellent optical purities.
An efficient synthesis of (R)-carnitine
Kasai,Sakaguchi
, p. 1211 - 1212 (2007/10/02)
An efficient synthesis of (R)-carnitine hydrochloride is described. The starting material is obtained by microbial resolution of (RS)-2,3-dichloro-1-propanol.
Process for preparing carnitine
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, (2008/06/13)
A process for preparing carnitine which comprises asymmetrically hydrogenating a γ-halogeno-β-keto ester represented by formula (I): STR1 wherein X represents a chlorine atom or a bromine atom; and R represents a lower alkyl group, in the presence of a ruthenium-optically active phosphine complex represented by formula (II), (III) or (IV): wherein L represents 2,2'-bis(di-p-R1 -phenylphosphino)- 1,1'-binaphthyl of formula (III): STR2 wherein R1 represents a hydrogen atom, a methyl group, or a t-butyl group; R2 represents a lower alkyl group or a trifluoromethyl group; and X is as defined above, as a catalyst at a temperature of from 70° to 150° C. to obtain an optically active alcohol represented by formula (VI): STR3 wherein X and R are as defined above, and then reacting the optically active alcohol as obtained with trimethylamine without isolation, is disclosed.
Enzymatic Hydrolysis of Alkyl 3,4-Epoxybutyrates. A New Route to (R)-(-)-Carnitine Chloride
Bianchi, Daniele,Cabri, Walter,Cesti, Pietro,Francalanci, Franco,Ricci, Marco
, p. 104 - 107 (2007/10/02)
The enzyme-catalyzed hydrolysis of alkyl 3,4-epoxybutyrates to the corresponding epoxy acids is reported.By using esterases the reaction occurred with good stereoselectivity leading to optically active unreacted esters of R configuration.With proteases the stereoselectivity was reversed, and the S enantiomer of the unreacted ester was recovered, albeit in lover enantiomeric excess.Finally, upon preliminary optimization of the reaction conditions, a new synthesis of (R)-(-)-carnitine chloride by the successive use of a stereoselective and of a nonstereoselective enzymatic hydrolysis is shown.
