139237-97-1Relevant articles and documents
(3S)-3-Hydroxyquinidine, the Major Biotransformation Product of Quinidine. Synthesis and Conformational Studies. X-Ray Molecular Structure of (3S)-3-Hydroxyquinidine Methanesulphonate
Carroll, F. Ivy,Abraham, Philip,Gaetano, Kevan,Mascarella, S. Wayne,Wohl, Ronald A.,et al.
, p. 3017 - 3026 (1991)
(3S)-3-Hydroxyquinidine, the major metabolite of the Cinchona alkaloid quinidine, was prepared by synthetic chemical modification or microbial oxidation of quinidine.The structure of this metabolite has been demonstrated to be (3S)-3-hydroxyquinidine by 1H and 13C NMR, IR, UV and mass spectral analysis.Previously published comparisons of the 13C NMR spectra of 3-hydroxyquinidine and model compounds were used to establish the absolute stereochemistry of the metabolite (see ref. 8).This assignment has been verified by single-crystal X-ray analysis of (3S)-3-hydroxyquinidine methanesulphonate.The gas- and solution-phase conformational preference of the metabolite derived from molecular modelling and NOE studies are compared with the conformation observed by X-ray crystallography.
Positional isomerization of quinine and quinidine via rhodium on alumina catalysis: Practical one-step synthesis of Δ3,10-isoquinine and Δ3,10-isoquinidine
Portlock, David E.,Naskar, Dinabandhu,West, Laura,Seibel, William L.,Gu, Titan,Krauss, Howard J.,Peng, X. Sean,Dybas, Paul M.,Soyke, Edward G.,Ashton, Stephen B.,Burton, Jonathan
, p. 5365 - 5368 (2007/10/03)
The synthesis of Δ3,10-isoquinine (5Z,5E) and Δ3,10-isoquinidine (6Z,6E) was achieved in one-step through positional isomerization of the terminal alkene in the parent cinchona alkaloids using catalytic amounts of 5% Rh/Al2O3 and excess hydrochloric acid in refluxing 50% aqueous EtOH. The products were obtained in good yields as a mixture of E and Z geometric isomers and fully characterized using spectroscopic methods.
Heterogeneous Enantioselective Hydrogenation of Activated Ketones Catalyzed by Modified Pt-Catalysts: A Systematic Structure-Selectivity Study
Exner, Christian,Pfaltz, Andreas,Studer, Martin,Blaser, Hans-Ulrich
, p. 1253 - 1260 (2007/10/03)
A systematic structure-selectivity study was carried out for the enantioselective hydrogenation of activated ketones with chirally modified Pt/Al2O3 catalysts. For this, 18 modifiers containing an extended aromatic system able to form a strong adsorption complex with the Pt surface, and a suitable chiral group with an amino function capable to interact with the keto group of the substrate (HCd, Qd, HCn, Qn, and semi-synthetic derivatives, as well as synthetic analogues) were prepared and tested on 8 different activated ketones in AcOH and toluene under standard conditions. It was found that relatively small structural changes of the substrate and/or modifier structures strongly affected the enantioselectivity, and that no "best" modifier exists for all substrates. The highest ees for all substrates were obtained with quinuclidine-derived modifiers in combination with naphthalene or quinoline rings, either in AcOH (substrates 1-5 and 8, all carrying an sp3 carbon next to the keto group) or toluene (6 and 7, with an sp2 carbon next to the ketone). The presence and nature of the substituent R′ at the quinuclidine significantly affected the ee (positive and negative effects). Certain combinations of an aromatic system and an amino function were preferred: For the quinuclidine moiety, quinoline and to a somewhat lesser extent naphthalene were a better match, while for the pyrrolidinylmethyl group anthracene was better suited. Methylation of the OH group often had a positive effect for hydrogenations in AcOH but not in toluene. With the exception of 8, higher ees were obtained for the Cd/ Qn series [leading to (R)-products] than for the Cn/ Qd series [leading to (S)-products]. In several cases, opposite structure-selectivity trends were detected when comparing reactions in toluene and AcOH, indicating a significant influence of the solvent.
