Brunner, Henri and Rosenboem, Sabine (2000) Enantioselective catalyses CXXXV. Stereoselective hydrogenation of folic acid and 2-methylquinoxaline with optically active rhodium(I)-phosphane complexes. MONATSHEFTE FUR CHEMIE, 131 (12). pp. 1371-1382. ISSN 0026-9247
Full text not available from this repository. (Request a copy)Abstract
In the hydrogenation of the C=N double bonds of the pyrazine ring of folic acid to 5,6,7,8-tetrahydrofolic acid a new asymmetric center is formed at C6 of the pteridine system. With rhodium(r) catalysts made from optically active phosphanes, which are immobilized on silical gel, the hydrogenation in aqueous solution can be controlled stereoselectively. The highest diastereomeric excess of ca. 40% is obtained with (-)-BPPM containing catalysts. The hydrogenation of the biomolecule folic acid in aqueous solution is also possible homogeneously with rhodium(I)phosphane catalysts, the ligands of which contain sulfonic acid groups and polyether fragments. The homogeneous hydrogenations proceed slower and with somewhat reduced diastereoselectivities compared to the heterogeneous catalyses. The hydrogenation of 2-methylquinoxaline is a model system for the reduction of folic acid. The usual rhodium(I)-phosphane catalysts afford only small enantioselectivities.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | C2-SYMMETRICAL BIS(PHOSPHOLANES); ASYMMETRIC CATALYSIS; REDUCTION; DIPHOSPHINE; enantioselectivity; diastereoselectivity; hydrogenation; folic acid; leucovorin; 2-methylquinoxaline; Rhodium(I) catalysts |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie > Alumni or Retired Professors > Prof. Dr. Henri Brunner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 15 Mar 2022 06:47 |
| Last Modified: | 15 Mar 2022 06:47 |
| URI: | https://pred.uni-regensburg.de/id/eprint/42023 |
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