No / The separation of racemates into pure enantiomers through crystallization is an important industrial process. This study provides further validation of a novel, predictive approach for spontaneous resolution in which crystal structure prediction simulations are used to explore the relative stabilities of racemic solids versus enantiopure solids. 2-(4-Hydroxyphenyl)-2,5,5-trimethylpyrrolidine-1-oxy (compound 1) has previously been shown to be a racemic conglomerate, while a similar compound, 2-(3-hydroxyphenyl)-2,5,5-trimethylpyrrolidine-1-oxy (compound 2), was not. A conformational search using the Dreiding force field revealed 10 conformational minima for compound 1, and 20 for compound 2. Atomic charges were calculated using unrestricted DFT B3LYP 6-311G** optimized structures, and a crystal structure prediction was performed using the Dreiding force field, considering all low-energy gas-phase conformations and all relevant space groups. Analysis of the predicted crystal structures suggests that compound 1 is a racemic conglomerate, but compound 2 is not. This is in agreement with the experimental evidence.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/4621 |
| Date | January 2008 |
| Creators | Gourlay, Matthew D., Kendrick, John, Leusen, Frank J.J. |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Article, No full-text available in the repository |
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