Cinchonine/cinchonidine

Detection. Cinchonine is sparingly soluble in all ordinary solvents, is not fluorescent in dilute sulphuric acid, is dextrorotatory, forms a soluble tartrate and hydriodide and does not give the thalleioquin reaction. Hesse s homocinchonine has been shown to be impure cinchonine. Cinchonidine, C49H22ON2. This alkaloid occurs in most varieties of cinchona bark, but especially in C. succiruhra. 

The use of compounds with activated methylene protons (doubly activated) enables the use of a mild base during the Neber reaction to 277-azirines. Using ketoxime 4-toluenesulfonates of 3-oxocarboxylic esters 539 as starting materials and a catalytic quantity of chiral tertiary base for the reaction, moderate to high enantioselectivity (44-82% ee) was achieved (equation 240). This asymmetric conversion was observed for the three pairs of Cinchona alkaloids (Cinchonine/Cinchonidine, Quinine/Quinidine and Dihydro-quinine/Dihydroquinidine). When the pseudoenantiomers of the alkaloid bases were used, opposite enantioselectivity was observed in the reaction. This fact shows that the absolute configuration of the predominant azirine can be controlled by base selection. 

Rubiaceae Cinchona officinalis Quinine Quininidine Cinchonine Cinchonidine... 

The ordinary testB for quinin, as mentioned above, distinguish between that alkaloid and quinidin on the one hand, and cinchonin, cinchonidin, and cinchoni-cin on the other. 

The pseudoenantiomeric catalysts derived from the alkaloid pairs cinchonine/cinchonidine and quinidine/quinine (1/4 or 2/5, respectively) are related as diastereomers but are enantiomeric with respect to the front working-face defined by carbons 8 and 9. 

Cinchonine, cbz-L-Trp, Fmoc-L-Trp MAA, 4-VP/ EDMA S toluene/ dodecanol Cinchonine/ cinchonidine, cbz-rac-Trp, Fmoc-rac-Trp [157]... 

Leaves of Cinchona succirubra Pav. from a trial plantation in the north of Thailand have been reported to contain the typical bases of quinoline alkaloids (cinchonine, cinchonidine, quinidine, quinine, di-hydroquinidine, and dihydroquinine) together with the indole bases quina-mine and 3-epiquinamine (97,98). 10-Methoxycinchonamine (92) has also been isolated from this plant for the first time. Except for the inclusion of alkaloid 92, the alkaloid pattern in C. succirubra is the same as that in the cross-species C. succirubra x C. ledgeriana from Guatemala. 

Spectra for the diastereoisomeric pairs quinine-quinidine, cinchonine-cinchonidine alkaloids are mirror images of each other and mixtures have been determined using CD detection [57]. Spectra for the pilocarpine-isopilocarpine pair were such low quality that they could be used only for qualitative distinction. CD detection combined with UV detection was used to measure enantiomeric excesses in mixtures of L-hyoscyamine and atropine, i.e. racemic hyoscyamine. This subject is returned to in greater depth later. 

Using (2) as catalyst provided the (R) enantiomer in 99% yield, 78% ee. The key introduction of asynunetry during the synthesis of (+)-podocarp-8(14)-en-13-one was the phase-transfer-catalyzed Robinson annulation of 6-methoxy-l-methyl-2-tetralone with ethyl vinyl ketone. The authors carried out a comparative study of the A/-(4-trifluoromethyl)benzyl derivatives of cinchonine, cinchonidine, dihydrocinchonine, and dihydrocinchonidine and found that (5) produced the highest ee of the desired (S) enantiomer at —45 °C using toluene and 60% aq KOH (eq 10). ... 

Main components 5-15% bitter tasting alkaloids, mainly chinine, chinidine, cinchonine, cinchonidine, as well as 3-5% tannins, up to 2% chinovin (a bitter tasting triterpene glycoside), resins, starch. 

Asymmetric Michael additions can also be performed under phase-transfer conditions with an achiral base in the presence of a chiral quaternary ammonium salt as a phase-transfer agent. Conn and coworkers conducted the Michael addition of 2-propyl-l-indanone (13) to methyl vinyl ketone under biphasic conditions (aq 50% NaOH/toluene) using the cinchonine/cinchonidine-derived chiral phase-transfer catalysts (PTCs), 14a and 14b, as a catalyst (Scheme 9.5). However, only low to... 

Protein biosynthesis is essential for all cells and thus provides another important target. Indeed, a number of alkaloids have been detected (although not too many have been studied in this context) which inhibit protein biosynthesis in vitro. Emetine from Cephaelis ipecacuanha (Rubiaceae) is the most potent plant constituent other alkaloids with the same ability include harringtonine, homoharringtonine, cryptopleurine, tubulosine, hemanthamine, lycorine, narciclasine, pretazettine, pseudolycorine, tylocrepine, and tylopherine [5] and furthermore, ajmaline, berberine, boldine, cinchonine, cinchonidine, harmalin, harmin, lobeline, norharman, papaverine, quinidine, quinine, salsoline, sanguinarine,... 

Ajmaline, berbamine, berberine, boldine, cinchonine, cinchonidine, ergometrine, harmalin, harmin, lobeline, norharman, papaverine, quinidine, quinine, sanguinarine, and solanine affect more than one of the basic... 

Solubility of Cinchonine, Cinchonidine, Quinine, and Quinidine IN Several Solvents at i8°-22°. 

In addition to quinine and quinidine, the following Cinchona alkaloids have also been studied cinchonine, cinchonidine, hydroquinidine, apo-quinine, and epiquinine. 

Quinine, dihydioquinine, 2 -dihydroquininone and 2 -quininone were baseline resolved in 25 min on a C g column (2 = 226nm) using a 22/78 aceonitrile/water (0.4% w/v ammonium acetate to pH 3.3 with acetic acid) mobile phase [1501]. Cinchonine, cinchonidine, and their metabolites were separated on the same colunm under similar conditions. 

Investigation of the Michael addition reaction of phosphonate carba-nions to a-nitroalkenes revealed that diethyl ether, used either as an achiral additive for the cinchonine or a mixture of cinchonine/cinchonidine catalysts or as a solvent, delivered different stereoisomers of y-nitroalkylpho-sphonates (203) than in THF, often with a reversal of enantioselectivity (Scheme 71). ... 

Seeler AO, Dusenbery E, Malanga C 1943 The comparative activity of quinine, quinidine, cinchonine, cinchonidine and quinoidine against Plasmodium lophurae infections of Pekin ducklings. J Pharmacol Exp Ther 78 159-163... 

Tsimachidis et al." used heptakis-(2,6-di-0)methyl-(3-CD (HDM-(3-CD) for the separation of quinine/quinidine and cinchonine/cinchonidine diastereomer pairs. They used coated (with polyacrylamide) and uncoated capillaries, both 50 p.m i.d., and 48/40 cm total length/effective length. The polyacrylamide layer reduced the EOF and improved the enantioseparation and the reproducibility of the migration time. At optimized conditions, i.e., ammonium acetate BGE with pH 5.0 containing 7-mM HDM-(3-CD, baseline separation of both pairs within 12 minutes was obtained. 

MIPS prepared with quinine as template [47] were employed to separate quin-ine/quinidine and cinchonine/cinchonidine diastereomers and also ( )-ephedrine and ( )-norephedrine enantiomers. Eluents, such as acetic acid/acetonitrile and acetic acid/methanol, were used in various proportions. 

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