L‐Carnitine. Novel Synthesis and Determination of the Optical Purity

Abstract

A ncw route to L-carnitine (1) based on the resolution of the triniethylanimoniuni derivative 5 is described. The enantiomeric purity of 1 is determined by 'H-NMR of its 0-acetyl hydrochloride 11 using [Eu(hfc),] aschiral shift reagent. The optical rotation of 1 with an enantiomeric purity > 99 'YO is [a]:: = -31.3" (r = 10, H,O).

Synthesis of γ‐Aminobutyric Acid Analogs

“…Alternatively, reaction of trimethylamine and L-tartaric acid with epichlorohydrin yields the (3-chloro-2-hydroxypropyl)trimethylammonium tartrate salts which were resolved by crystallization and converted to enantiomerically pure (R)-carnitine in two steps [163].…”

Enantiomeric purity determination of acetyl-l-carnitine by NMR with chiral lanthanide shift reagents

“…There are some reports concerning the HPLC determination of the d-enantiomer contained in l-AC [16][17][18][19][20]. In the NMR method, Voeffray et al [21] reported enantiomeric purity of l-AC employing tris [3-(heptafluoropropylhydroxymethylene CSR. As little as 0.5% of d-AC could be discerned, however, effects of the kinds of CSRs and its concentration on the enantiomer signal separation were not studied at that time.…”

An Efficient Synthesis of Enantiomeric (S)-Phosphocarnitine

“…[1] Increasing use of this compound primarily as a dietary supplement has resulted in the elaboration of numerous synthetic procedures, including transformations of homochiral starting materials, [2Ϫ6] asymmetric synthesis, [7Ϫ14] applications of enzymes and related technologies [15Ϫ22] and also optical resolution of the racemic carnitine or its precursors. [23,24] Various analogues of carnitine have been synthesised in order to study its mode of action and to reveal the structural features of binding sites. [25Ϫ34] Among them, phosphocarnitine (2), an analogue in which the carboxy group has been replaced with a phosphoryl residue, has recently been obtained.…”