36060-84-1Relevant articles and documents
Carica papaya lipase catalysed resolution of β-amino esters for the highly enantioselective synthesis of (S)-dapoxetine
You, Pengyong,Qiu, Jian,Su, Erzheng,Wei, Dongzhi
, p. 557 - 565 (2013/03/13)
An efficient synthesis of the (S)-3-amino-3-phenylpropanoic acid enantiomer has been achieved by Carica papaya lipase (CPL) catalysed enantioselective alcoholysis of the corresponding racemic N-protected 2,2,2-trifluoroethyl esters in an organic solvent. A high enantioselectivity (E > 200) was achieved by two strategies that involved engineering of the substrates and optimization of the reaction conditions. Based on the resolution of a series of amino acids, it was found that the structure of the substrate has a profound effect on the CPL-catalysed resolution. The enantioselectivity and reaction rate were significantly enhanced by switching the conventional methyl ester to an activated trifluoroethyl ester. When considering steric effects, the substituted phenyl and amino groups should not both be large for the CPL-catalysed resolution. The mechanism of the CPL-catalysed enantioselective alcoholoysis of the amino acids is discussed to delineate the substrate requirements for CPL-catalysed resolution. Finally, the reaction was scaled up, and the products were separated and obtained in good yields (≥ 80 %). The (S)-3-amino-3- phenylpropanoic acid obtained was used as a key chiral intermediate in the synthesis of (S)-dapoxetine with very high enantiomeric excess (> 99 %). A carica papaya lipase catalysed resolution of N-protected β-phenylalanine esters has been developed. High enantioselectivity was achieved by two strategies that involved engineering of the substrates and optimization of the reaction conditions. After 50 % conversion, the products were separated and used as key chiral intermediates for the synthesis of (S)-dapoxetine with > 99 % ee. Copyright
An efficient synthesis of new 2-aminomethyl-1,3,4-oxadiazoles from enantiomeric phenylglycine hydrazides
Kudelko, Agnieszka,Zieliński, Wojciech
experimental part, p. 1200 - 1206 (2009/04/10)
New derivatives of 2-aminomethyl-1,3,4-oxadiazole were synthesized in the reactions of N-protected phenylglycine hydrazides and triethyl orthoesters (orthoformate, orthoacetate, orthopropionate, orthobenzoate) in the presence of glacial acetic acid. Studies on the cleavage reactions of the acid-sensitive N-BOC and N-Ac 1,3,4-oxadiazoles are presented. Spectral characteristics of the compounds and attempts to elucidate the racemization phenomenon observed in products are also discussed.
Rational de novo design of NADH mimic for stereoselective reduction based on molecular orbital calculation
Eguchi, Tadashi,Fukuda, Miki,Toyooka, Yumiko,Kakinuma, Katsumi
, p. 705 - 714 (2007/10/03)
The methodology of rational design of NADH mimics in stereoselective reduction of carbonyl and imino groups based on molecular orbital calculation was described. The designed NADH mimics 1a and 1b were subjected to the reduction of benzoylformate and acetyliminophenylacetate. As expected from the calculations of the transition-states, the reduction with 1a proceeded with high stereoselectivity in both substrates, while 1b showed much lower chirality transfer.
