Resolution, aporphines

Natalinine (491), C25H23N05, amorphous, is a minor alkaloid of Berberis empetrifolia Lam. MS and high-resolution NMR established the skeletal structure, and CD indicated the (R) configuration (561). Natalinine may be derived biogenetically from catabolism of an aporphine-benzylisoquinoline dimer [such as pakistanine (92), a major co-occurring alkaloid] (561), or by rearrangement of a coyhaiquine (107)-type dimer (562). 

Isocalycinine (74) and discoguattine (75) are the only two aporphines of Guat-teria known to possess a 9,11-dioxygenated ring D, which had seemed to be a characteristic feature of Duguetia (Annonaceae) (67). Both alkaloids were isolated from G. discolor (24), and their structures were easily determined by the usual spectroscopic methods. In both, a meta-coupled AB system was the only outstanding feature recognizable in the H-NMR spectra which, however, had to be recorded in CSDSN to achieve adequate resolution and, in the case of isocalycinine (74), to confirm the location of the phenol function at C-9. 

Because benzylisoquinolines have been available synthetically (in racemic form) for decades, there is quite a bit of chemistry known regarding their use as key intermediates in the synthesis of a number of more complex isoquinoline alkaloids. The asymmetric synthesis of benzylisoquinolines has been used to complete total synthesis of representative members of several of these alkaloid classes. As shown in Figure 6, the protoberberine alkaloid norcoralydine, the aporphine alkaloid ocoteine, the isopavine alkaloid reframoline and the morphinan 0-methylflavinantine have been made available in optically active form for the first time (except by isolation or resolution) using this approach. 

EP-10 (82), C39H42OgN2 (666.2941), mp 205-210°, was isolated from an extract (EtOH) of the whole plant of the Taiwanese T. fauriei Hayata in 1986 [35]. The UV spectrum showed absorption maxima at 210, 270, 294, and 300 nm, and was similar to those of the aporphine-pavine alkaloids pennsylpavine (83) and pennsylpavoline (84) that had been isolated from T. polygamum Muhl. some twenty years earlier [135]. The specific rotation of the alkaloid was not reported, nor was any CD spectral data provided. The high resolution EIMS showed a parent ion and base peak at m/z 666.2953 (666.2641, calcd. for C39H42OgN2) with other important fragment... 

Demethylsonodione (7), a p-quinonoid aporphine, was obtained as greenish prisms. Its molecular formula was determined as C19H17O5N by high-resolution electron impact mass spectrometry (HREIMS) at m/z 339.1098 [M]+ [24]. The UV spectrum with maxima at 219, 283, 336, and 642 nm was typical of a p-quinonoid aporphine skeleton [53]. In its IR spectrum, absorption bands at 3440 cm 1 (phenolic hydroxyl) and 1635 cm 1 (carbonyl) were apparent. The H-NMR spectrum indicated signals... 

A two-phase solvent system composed of chloroform-methanol-dilute inorganic acid has been used for the separation of a variety of alkaloids including isoquinoline alkaloids, naphthyl-tetrahydroisoquinoline alkaloids, flavo-noid alkaloids, pentacyclic aromatic alkaloids, diterpenoid alkaloids, aporphine alkaloids, etc. The following example illustrates a typical systematic solvent selection for the separation of pahnatine, berberine, epiberberine, and copti-sine from the cmde alkaloids of Coptis chinensis Franch by analytical HSCCC. In Fig. 1, nine chromatograms are arranged in such a way that the effects of the concentration of HCl (0.3-0.1 M) and the relative volumes of methanol (4 3 2—4 1.5 2, v/v) on the separation of alkaloids from C. chinensis Franch are each readOy observed. As the concentration of HCl is reduced from 0.3 to 0.1 M in the solvent system, the retention time of alkaloids and their peak resolution are increased. A similar effect is also produced by decreasing the relative volumes of methanol in the solvent system from 4 3 2 to 4 1.5 2). Among those. 

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