Emergence of a single solid chiral state from a nearly racemic amino acid derivative.
- W. Noorduin, Toshiko Izumi, D. Blackmond
- ChemistryJournal of the American Chemical Society
- 4 January 2008
Attrition-enhanced dissolution and recrystallization processes based on solubility considerations of the Gibbs−Thomson rule, coupled with solution-phase racemization, drive this near-equilibrium system inexorably to single chirality in the solid phase.
The driving mechanism behind attrition-enhanced deracemization.
- W. Noorduin, W. V. van Enckevort, E. Vlieg
- Materials ScienceAngewandte Chemie
- 2 November 2010
The transformation of the enantiomorphic but intrinsically achiral salt NaClO3 into single chirality was recently demonstrated by Viedma by simply grinding the crystals in a saturated solution, and it is found that the solution phase has a surprisingly large excess of molecules with the handedness of the minor solid phase, which becomes more pronounced upon enrichment of the solid phase in the opposite enantiomer.
High-performance liquid chromatographic separation of the enantiomers of unusual alpha-amino acid analogues.
- A. Péter, E. Olajos, D. Armstrong
- ChemistryJournal of Chromatography A
- 25 February 2000
Peptide α/310-Helix Dimorphism in the Crystal State
- M. Crisma, M. Saviano, A. Moretto, Q. Broxterman, B. Kaptein, C. Toniolo
- Chemistry, Materials Science
- 21 November 2007
The fully Cα-methylated homo-peptide Ac-[l-(αMe)Val]7-NHiPr is completely 310-helical when its crystals are grown from a methanol solution, whereas it is α-helical when crystallized from HFIP…
(alphaMe)Nva: stereoselective syntheses and preferred conformations of selected model peptides.
- A. Moretto, C. Peggion, C. Cativiela
- Chemistry, BiologyJournal of Peptide Research
- 1 November 2000
This study reinforced previous conclusions that peptides based on alpha-amino acids with a Calpha-methyl substituent and aCalpha-linear alkyl substituents are characterized by a strong tendency to fold into turn and helical structures.
Dipeptide-catalyzed asymmetric aldol condensation of acetone with (N-alkylated) isatins.
- Gianluigi Luppi, P. Cozzi, M. Monari, B. Kaptein, Q. Broxterman, C. Tomasini
- ChemistryJournal of Organic Chemistry
- 5 August 2005
The aldol condensation of acetone with several isatins is described, resulting in the preferential formation of the (R-enantiomer), and the absolute configuration of the newly formed chiral center has been assigned.
Complete chiral symmetry breaking of an amino acid derivative directed by circularly polarized light.
- W. Noorduin, Arno A. C. Bode, E. Vlieg
- ChemistryNature Chemistry
- 1 December 2009
It is demonstrated that irradiation of a racemic amino acid derivative with CPL leads to a small amount of chiral induction that can be amplified readily to give an enantiopure solid phase.
From Ostwald ripening to single chirality.
- W. Noorduin, E. Vlieg, R. Kellogg, B. Kaptein
- Materials ScienceAngewandte Chemie
- 14 December 2009
The basic concepts developed by Ostwald will be introduced, followed by a summary of the current status of grinding-induced asymmetric transformations, and how close Ostwald himself came to discovering this technique.
Attrition-Enhanced Deracemization in the Synthesis of Clopidogrel - A Practical Application of a New Discovery
- M. V. D. Meijden, M. Leeman, R. Kellogg
- Chemistry, Biology
- 4 November 2009
The recently discovered technique of deracemization by means of attrition-induced grinding of a solid conglomerate in contact with a solution wherein racemization occurs has been used with a…
Complete deracemization by attrition-enhanced ostwald ripening elucidated.
- W. Noorduin, H. Meekes, E. Vlieg
- Materials Science, ChemistryAngewandte Chemie
- 11 August 2008
Direct resolution by crystallization of racemic mixtures, induced by seeding or by adding tailor-made additives, constitutes an attractive alternative to separation using diastereomeric salts.…
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