10017-44-4Relevant articles and documents
An efficient synthesis of (R)-carnitine
Kasai,Sakaguchi
, p. 1211 - 1212 (1992)
An efficient synthesis of (R)-carnitine hydrochloride is described. The starting material is obtained by microbial resolution of (RS)-2,3-dichloro-1-propanol.
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
, p. 371 - 372 (2011)
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 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.
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.
Process for preparing L-carnitine and salts thereof
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, (2008/06/13)
L-carnitine and salts thereof are resolved from DL-carnitine by the use as a resolving agent of dibenzoyl-L(+)tartaric acid. L-carnitine is known as vitamin BT and is useful as a medicine.
