97443-96-4Relevant academic research and scientific papers
A Concise Enantiodivergent Synthesis of Equol
Uemura, Takahito,Saito, Yusuke,Sonoda, Motohiro,Tanimori, Shinji
, p. 693 - 696 (2020/12/23)
Equol, a nonsteroidal estrogen produced from the metabolism of the isoflavonoid phytoestrogen daidzein, has been synthesized as both enantioenriched forms based on MacMillan's α-Arylation of carbonyl compound mediated by amino acid derived indazolidinones and copper precatalysts. The natural form of (S)-equol and its enantiomer (R)-equol have been synthesized in 8 steps from 2,4-dimethoxybenzaldehyde with good enantiomeric purity (90% ee and 90% ee, respectively).
Herstellung enantiomerenreiner cis- oder trans-konfigurierter 2-(tert-Butyl)-3-methylimidazolidin-4-one aus den Aminosaeuren (S)-Alanin, (S)-Phenylalanin, (R)-Phenylglycin, (S)-Methionin und (S)-Valin.
Naef, Reto,Seebach, Dieter
, p. 135 - 143 (2007/10/02)
In contrast to α-hydroxy and α-mercapto carboxylic acids, simple α-amino acids do not form acetal-type derivatives (2, X=NH) with pivalaldehyde.For the generation of amino-acid-derived chiral, nonracemic enolates (cf.3), and hence, for the α-alkylation of amino acids without racemization and without an external chiral auxiliary, the imidazolidinones 12-14 were prepared diastereoselectively.To this end, the methyl or ethyl esters of amino-acid hydrochlorides were first converted to N-methylamides of amino acids which in turn were condensed with pivalaldehyde to give (neopentylidenamino)amides (11).These Schiff bases could be cyclized either to trans- or to cis-imidazolidinones (12, 14 and 13, respectively), which were obtained in enantiomerically pure form after recrystallization.The enantiomeric purities were confirmed by HPLC with chiral stationary phases or by 1H-NMR spectroscopy in the presence of chiral shift reagents.The configurations (cis, trans) were assigned by NOE measurements on 300- or 360-MHz 1H-NMR spectrometers.
