Viedma ripening is a deracemization process that has been used to deracemize a range of chiral molecules. The method has two major requirements: the compound needs to crystallize as a conglomerate and it needs to be racemizable under the crystallization conditions. Although conglomerate formation can be induced in different ways, the number of racemization methods is still rather limited. To extend the scope of Viedma ripening, in the present research we applied UV-light-induced racemization in a Viedma ripening process, and report the successful deracemization of a BINOL derivative crystallizing as a conglomerate. Irradiation by UV light activates the target compound in combination with an organic base, required to promote the excited-state proton transfer (ESPT), leading thereafter to racemization. This offers a new tool towards the development of Viedma ripening processes, by using a cheap and "green" catalytic source like UV light to racemize suitable chiral compounds.
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http://dx.doi.org/10.1002/chem.201904382 | DOI Listing |
Chemphyschem
September 2023
Laboratoire des IMRCP, UMR au CNRS No. 5623, Université Paul Sabatier 31062, Toulouse Cedex, France.
Attrition-enhanced chiral symmetry breaking in crystals, known as Viedma deracemization, is a promising method for converting racemic solid phases into enantiomerically pure ones under non-equilibrium conditions. However, many aspects of this process remain unclear. In this study, we present a new investigation into Viedma deracemization using a comprehensive kinetic rate equation continuous model based on classical primary nucleation theory, crystal growth, and Ostwald ripening.
View Article and Find Full Text PDFChirality
September 2023
Center for Computational Sciences, University of Tsukuba, Tsukuba, Japan.
Chemistry
June 2023
Department of Molecular Chemistry, Materials and Catalysis, Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Place Louis Pasteur, 1 bte L4.01.06, 1348, Louvain-La-Neuve, Belgium.
We report the first case of mechanochemical deracemization by using liquid-assisted abrasive grinding. The target molecule is a precursor of Paclobutrazol, an important fungicide and plant growth inhibitor. Using mechanochemical deracemization, we are even able to transform a 10 % ee scalemic mixture of this latter in an enantioenriched product of 97 % ee in a couple of hours.
View Article and Find Full Text PDFPhys Chem Chem Phys
November 2022
Bashkir State University, 32 Zaki Validi str., Ufa, Russia.
Chiral crystals remain one of the probable sources of first minute chiral symmetry breaking, a trigger that potentially causes an as-yet unknown type of asymmetric autocatalysis during the formation of chiral biopolymers under the conditions of the Archean Earth. Therefore, studying adsorption processes on the surface of such crystals may help improve the understanding of the nature of the initial chiral shift. The adsorptive activity of non-porous crystals with respect to the majority of organic molecules essentially depends on the ability of a crystal surface to engage in specific intermolecular interactions.
View Article and Find Full Text PDFOrg Process Res Dev
April 2022
Department of Chemical Engineering and Analytical Science, University of Manchester, M13 9PL Manchester, U.K.
Enantiomeric purity is of prime importance for several industries, specifically in the production of pharmaceuticals. Crystallization processes can be used to obtain pure enantiomers in a suitable solid form. However, some process variants inherently rely on kinetic enhancement (preferential crystallization) of the desired enantiomer or on complex interactions of several phenomena (e.
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