146912-63-2Relevant academic research and scientific papers
Asymmetric synthesis of (S)-dihydrokavain from l-malic acid
Eskici, Mustafa,Karanfil, Abdullah,?zer, M. Sabih,Kabak, Yal??n,Durucasu, ?nci
supporting information, p. 2382 - 2390 (2018/10/20)
A practical and efficient asymmetric synthesis of (S)-dihydrokavain from known ethyl (S)-2-hydroxy-4-phenylbutanoate which is, in turn, readily available from l-malic acid as a cheap chiral pool material is described using regioselective ring-opening of the 1,2-cyclic sulfate with lithium-3,3,3-triethoxypropiolate and subsequent HgO/H2SO4-mediated lactonization as the key steps. Its opposite enantiomer (R)-dihydrokavain was also synthesized from d-malic acid using the same sequences of reactions for the purpose of optical purity determination.
Lipase activity of Lecitase Ultra: characterization and applications in enantioselective reactions
Mishra, Mithilesh Kumar,Kumaraguru, Thenkrishnan,Sheelu, Gurrala,Fadnavis, Nitin W.
experimental part, p. 2854 - 2860 (2010/04/05)
The general properties of Lecitase Ultra, a phospholipase manufactured and marketed by Novozymes, Denmark, have been studied after purification by ultrafiltration. The enzyme has a molecular mass of 35 KD, pH-optimum of 8.5, and appears to possess a single active site which exhibits both the lipase and phospholipase activities that increase in the presence of Ca2+ and Mg2+ ions. The enzyme is inhibited by heavy metal ions and surfactants, and does not accept p-nitrophenyl acetate and glycerol triacetate. Substrates, such as glycerol tributyrate and p-nitrophenyl palmitate, esters of N-acetyl-α-amino acids and α-hydroxy acids are readily accepted. Amino acids with aliphatic residues, such as alanine, isoleucine, and methionine, are hydrolyzed with high enantioselectivity for the l-enantiomer (E >100), but amino acids with aromatic residues such as phenylalanine and phenylglycine, and esters of α-hydroxy acids are hydrolyzed with low enantioselectivity (E = 1-5). Immobilization of the enzyme in a gelatin matrix (gelozyme) leads to a marginal improvement in the enantioselectivity for these substrates. However, a dramatic improvement in enantioselectivity is observed for ethyl 2-hydroxy-4-oxo-4-phenylbutyrate (E value increases from 4.5 to 19.5 with S-selectivity). Similarly, glycidate esters, such as ethyl trans-(±)-3-phenyl glycidate and methyl trans-(±)-3-(4-methoxyphenyl) glycidate, are selectively hydrolyzed with a remarkable selectivity towards the (2S,3R)-enantiomer providing unreacted (2R,3S)-glycidate esters (ee >99%, conversion 52-55%) by the immobilized enzyme.
Enantio- and regiospecific reduction of ethyl 4-phenyl-2,4-dioxobutyrate with baker's yeast: Preparation of (R)-HPB ester
Fadnavis, Nitin W.,Radhika, Kasiraman R.
, p. 3443 - 3447 (2007/10/03)
Ethyl 2,4-dioxo-4-phenylbutyrate obtained by condensation of acetophenone with diethyl oxalate is reduced enantio- and regiospecifically by baker's yeast in a diisopropyl ether/water two-phase system to give (-)-ethyl (R)-2-hydroxy-4-oxo-4-phenylbutyrate with an ee = 98% in 80% isolated yield. The hydroxyester was hydrogenated over Pd-C to obtain (-)-ethyl (R)-2-hydroxy-4-phenylbutyrate (HPB ester), an important intermediate for the synthesis of ACE inhibitors. Prolonged contact of the reduction product with baker's yeast produced 3-phenyl 3-oxo propanol in 90% yield.
A practical synthesis of ethyl (R)- and (S)-2-hydroxy-4-phenylbutanoate and D-homophenylalanine ethyl ester hydrochloride from L-malic acid
Lin, Wen-Qing,He, Ze,Jing, Yi,Cui, Xin,Liu, Hui,Mi, Ai-Qiao
, p. 1583 - 1587 (2007/10/03)
With the readily available L-malic acid as starting material, both enantiomers of ethyl 2-hydroxyl-4-phenylbutanoates and D-homophenylalanine ethyl ester hydrochloride were prepared conveniently in excellent optical purity and 64, 53 and 49% overall yield, respectively.
Synthesis of homochiral 2-hydroxy acids
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, (2008/06/13)
A process for the production of a homochiral 2-hydroxy carboxylic acid or salt thereof corresponding to general formula (I), wherein R represents one of formulae (II), (III), (IV), (V), wherein R' represents straight- or branched-chain alkyl or phenyl opt
Stereoselective routes to chiral 2-hydroxy-4-oxo acids and substituted 2-hydroxybutyrolactones using lactate dehydrogenases
Casy, Guy
, p. 8159 - 8162 (2007/10/02)
The enantioselective reduction 2,4-dioxo acids catalysed by lactate dehydrogenases provided access to 2-hydroxy-4-oxo acids of both S and R configuration. Subsequent diastereoselective chemical reduction affords 4-substituted 2-hydroxybutyrolactones.
