3 research outputs found
Solution-phase racemization in the presence of an enantiopure solid phase.
Solution-phase racemization
drives the evolution of single chirality
in the solid phase by the "chiral amnesia"
process first described by Viedma.
The current investigations lay the basis
for a better understanding of the mechanism
of the solid-phase deracemization
by uncoupling the chemical rate
processes associated with the interconversion
of enantiomers in the solution
phase from the physical processes associated
with solution-solid phase transfer
via dissolution and reaccretion of
molecules onto crystals. In addition,
the enantiomer concentration profiles
presented in this work, together with
an analytical treatment of the racemization
process in the presence of excess
enantiopure solid, unequivocally reconfirm
the validity of the Meyerhoffer
double solubility rule for systems
under solution racemization conditions
Chiral separation of substituted phenylalanine analogues using chiral palladium phosphine complexes with enantioselective liquid–liquid extraction
Chiral palladium phosphine complexes have been employed in the chiral separation of amino acids and phenylalanine analogues in particular. The use of (S)-xylyl-BINAP as a ligand for the palladium complex in enantioselective liquid–liquid extraction allowed the separation of the phenylalanine analogues with the highest operational selectivity reported to date. 31P NMR, FTIR, FIR, UV-Vis, CD and Raman spectroscopy methods have been applied to gain insight into the binding mechanism of the amino acid substrates with the chiral palladium phosphine complexes. A complexation in a bidentate fashion is proposed.
Enantiomerically pure beta-phenylalanine analogues from alpha-beta-phenylalanine mixtures in a single reactive extraction step
An efficient and selective method for the extraction of alpha-amino acids in preference over their beta-isomers using PdCl2(PPh3)(2) was discovered, which enables the separation of product mixtures obtained in the enantioselective enzymatic formation of beta-amino acids