33605-56-0Relevant articles and documents
The preparation method of the levodopa intermediate derivatives
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Paragraph 0076; 0077, (2017/10/13)
The invention relates to a preparation method for a levodopa intermediate derivative. The preparation method comprises: in a solvent, reacting 3, 4-dimethoxybenzene phenylalanine shown as formula I with (+)-tartaric acid derivative to obtain the salt of a [(-)-3, 4-dimethoxybenzene phenylalanine]2.(+)- tartaric acid derivative. The solvent includes an alcohol solvent and an ester solvent. The racemization method includes: in the solvent, under the action of an aldehyde or ketone catalyst, reacting the 3, 4-dimethoxybenzene phenylalanine shown as formula I at 0-90DEG C for 0.5-24 h. The preparation method for the levodopa intermediate derivative provided by the invention has simple steps, and the prepared enantiomer has high purity and is low in cost, thus being applicable to industrial production. (reaction formula).
GENERAL METHOD FOR THE ASYMMETRIC SYNTHESIS OF α-AMINO ACIDS VIA ALKYLATION OF THE CHIRAL NICKEL(II) SCHIFF BASE COMPLEXES OF GLYCINE AND ALANINE
Belokon, Yuri N.,Bakhmutov, Vladimir I.,Chernoglazova, Nina I.,Kochetkov, Konstantin A.,Vitt, Sergei V.,et al.
, p. 305 - 312 (2007/10/02)
Nickel(II) complexes of Schiff bases derived from (S)-o-benzaldehyde and alanine (3), or (S)-O-benzophenone and alanine (4), or glycine (5) have been used for the asymmetric synthesis of α-amino acids under a variety of conditions.The method of choice consists of the reaction of the corresponding complex with the appropriate alkyl halide in DMF at 25 deg C using solid NaOH as a catalyst.Low diastereoselective excess (d.e.) is observed for the alkylation of complex (3) with benzyl bromide and allyl bromide.Large selectivity (80 percent) is observed for the alkylation of complex (4).Optically pure(R)- and (S)-O-benzyl-α-methyl-α-amino acids were obtained (70-90 percent) after the alkylated diastereoisomeric complexes had been seperated on SiO2 and hydrolysed with aqueous HCl.The initial chiral reagents were recovered (80-92 percent).The alkylation of complex (5) gave (S)-alanine, (S)-valine, (S)-phenylalanine, (S)-tryptophan, (S)-isoleucine, (S)-2-aminohexanoic acid, and 3,4-dimethoxyphenylalanine with optical yields of 70-92 percent.The optically pure α-amino acids were obtained after the separation of the alkylated diastereoisomeric complexes on SiO2.The stereochemical mechanism of the alkylation reaction is discussed.