Dehydroaporphine alkaloids

E. TYPE VI - BENZYLISOQUINOLINE-APORPHINE, BENZYLISOQUINOLINE-OXOAPORPHINE, AND BENZYLISOQUINOLINE-DEHYDROAPORPHINE ALKALOIDS... 

The numbering of the aporphine ring in the following alkaloids (aporphines, dehydroaporphines, oxoaporphines) is according to accepted practice [1,102-106], and is illustrated in the structure of acutifolidine (40). 

Several new aporphine and berberine alkaloids which were uncovered in the period of the last ten years or so are from plants of the Anixmaceae such as the 7-hydroxyaporphine, dasymachaline (9) from Desmosdasymachatus [27], the dioxoaporphine, l,2,3-trimethoxy-4,5-dioxo-6a,7-dehydroaporphine (10) from Pseuduvaria macrophylla [28], the tetrasubstituted... 

Interest in the aporphine alkaloids has principally centred on the range and number of oxidised bases that have been discovered. A considerable number of 7-hydroxy and 7-methoxy aporphines have been isolated and both 7a and 73 forms have been encountered. These probably represent intermediates in the formation of dehydroaporphines, into which they are easily converted in the laboratory, by dehydration. Alkaloids of this type isolated include oliveroline (104, R =Me, R =H) and its A/-oxide ushinsunine which is the 7a-hydroxy isomer of oliveroline pachypodanthine (104, R =, R =Me), iv-methylpach-ypodanthine (104, R =R =Me) and its -oxide oliverine (105, Ri=R2=Me) and oliveridine (105, R =Me, R =H) and their iv-oxi-des the related secondary bases noroliverine (105, R =H, R =Me) and noroliveridine (105, R =R =H) polysuavine (106) guatterine (107, R=H) and its y-oxide polyalthine (107, R=... 

The separation and tentative characterization of aporphine and related alkaloids present in Nandina domestica Thunb. has been achieved using t.l.c.-g.c. The intensities of i.r. bands of aporphines in the 1480—1630 cm region have been used to determine the substitution pattern at C-1 and C-11 for a variety of aporphines and dehydroaporphines. ... 

More recently, the preparative value of VOCl3 and VOF3-TFA in chemical oxidation has been demonstrated (see Section III, on the pro-aporphine and promorphinane alkaloids) (415,462). Some other authors used the purified enzyme horseradish peroxidase (463). By this method the aporphine base (besides the quaternary dibenzopyrrocoline) is readily obtained from (S)-( + )-laudanosoline hydrobromide or from (/ )-(—)-laudanosoline methiodide with retention of the absolute configuration. The synthesis of 6a,7-dehydroaporphine bases was also carried out by making use of the benzyne reaction (439). Reduction of these substances affords the corresponding aporphine bases (439). The synthesis of isoquinoline alkaloids by lead tetraacetate oxidation was reviewed by Umezawa and Hoshino (343). 

The simplest derivatives of the tetrahydrobenzylisoquinoline alkaloids are the aporphine alkaloids (Fig. 32.12). Aporphine alkaloids (about 650) are widespread and occur in almost the same families as benzylisoquinoline alkaloids (Guinaudeau and Bruneton, 1993 Kametani and Honda, 1985). Several subgroups of aporphine alkaloids are known [noraporphines, dehydroaporphines (34), oxoaporphines (35), dimeric apor-phines, and phenanthrenes (36)] (Fig. 32.13) (Cave et al., 1987). The aporphine alkaloids present in members of the Annonaceae and in the genus Thalictrum (Ranunculaceae) have been reviewed (Cave et al., 1987 Schiff, 1987). 

Most of the alkaloids containing an isoquinoline structure that are considered are presented in the following order simple iso quinolines, isoquinolones, and phenethylammonium compounds benzyltetrahydroi-soquinolines bisbenzylisoquinolines and bisbenzyltetrahydroisoquino-lines protoberberines and tetrahydroprotoberberines proaporphines aporphinoids dehydroaporphines 7-substituted aporphines oxoapor-phines phenanthrenes miscellaneous isoquinohne-type alkaloids and nonisoquinoline alkaloids. 

The dehydroaporphines constitute a recently discovered sub-group of aporphine alkaloids- The naturally occurring members found to date are dehydrodicentrine, dehydroocopodine, dehydroglaucine, and the dimeric base dehydrothalicarpine. 

A. TYPE I - APORPHINE, NORAPORPHINE, DEHYDROAPORPHINE, AND OXOAPORPHINE ALKALOIDS... 

The aporphine and noraporphine (type I) alkaloids are the most numerous (48 alkaloids) and occur in all of the genera studied Gyrocarpus, Hernandia, Illigera, and Sparattanthelium), while the dehydroaporphine (subtype la, with 14 alkaloids) and oxoaporphine (subtype Ib, with 5 alkaloids) alkaloids were found in only two of them Hernandia and Illigera) (Table I see also Appendix). 

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