Dehydroaporphines

Recently, a photosensitized synthesis of phenanthrene heterocycles from 1- and 9-(aminoalkyl)phenanthrenes has been achieved109. Irradiation of l-(2-aminoethyl)phen-anthrene and m-DCNB in 9 1 acetonitrile water solution for 2 hours gives 70% of the aporphine 114 and 15% of the dehydroaporphine 115 with 87% conversion of starting material (equation 50). 

Kunitomo et al. reported that air oxidation of dehydroaporphines, including 2,10-dimethoxydehydroaporphine (84a), dehydronuciferine (85a), and dehydro-nantenine (86a), with tert-BuOK in DMSO gave corresponding A-meth-... 

The partial synthesis of 4,5-dioxoaporphine has been achieved. Preparation of cepharadione B (43), 2,10-dimethoxy-4,5-dioxodehydroaporphine (84d), 4,5-dioxodehydronantenine (86d), and 4,5-dioxodehydrocrebanine (87d) was achieved in DMSO by air oxidation of the corresponding dehydroaporphines with an alkali catalyst as described above (Section V,A,1). Oxidation of nan-... 

Pontevedrine (46) and cepharadione B (43) were also obtained by photooxidation of corresponding dehydroaporphines (Scheme 16). Pontevedrine was obtained by irradiation of an ethanol solution of dehydropontevedrine with a mercu-... 

Aerial oxidation of the dehydroaporphines (52)—(54) with alkali catalysts gives the corresponding oxoaporphines, 4,5-dioxoaporphines, and JV-methyl -aristolactams in low yields. The 4,5-dioxoaporphine (55) from the oxidation of (54) corresponds to 4,5-dioxodehydronantenine, which is found as a natural product in the dried fruits of Nandina domestica.34... 

Aporphine sensu stricto subtype Dehydroaporphine subtype... 

Dehydrostephalagine (84), a new dehydroaporphine which was found in G. sagotiana (45), does not require particular comment. Dehydronornuciferine (80) and O-methyldehydroisopiline (82) have been isolated from G. ouregou (39), where they cooccur with the corresponding noraporphines (41 and 50) and the N-formyl derivatives dehydroformouregine (83) and formouregine (51). The structure elucidation of dehydronornuciferine (80) and O-methyldehydroisopiline... 

Dehydroaporphines undergo both N- and C-7-protonation in trifluoroacetic acid, but it is the C-7-protonated immonium salt which is formed almost exclusively under equilibration conditions.41 Some C-6a- and C-7-deuteriated aporphines can, therefore, be prepared. The reaction of dehydronuciferine with dichlorocarbene yielded dehydronuciferine-7-carboxaldehyde. Reduction of this aldehyde with sodium cyanoborohydride afforded 7-methyldehydro-nuciferine.42... 

Oxidation of the tetrahydroisoquinoline (23) by thallium(m) trifluoroacetate in methanol leads to ocoteine (24) in 46% yield. When the same oxidizing reagent, in trifluoroacetic acid, was used in connection with the acetyl amide (25), 7V-acetyl3-methoxynornantenine (26) and the corresponding dehydroaporphine... 

The photo-oxidation of aporphines to dehydroaporphines has been described.48 A stereospecific and quantitative oxidation of (+)-glaucine (45) to dehydroglaucine (46) was achieved with Fusarium solani. Using this same micro-organism, (—)-glaucine was not metabolized, while ( )-glaucine was oxidized to the extent of 50%.49... 

A good method for the conversion of aporphines to dehydroaporphines involves catalytic dehydrogenation using 10% Pd-C in refluxing acetonitrile. Nuciferine,... 

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=... 

Derived from these bases, no doubt, by dehydration, several dehydroaporphines have been identified as natural products. These incluyde dehydroisolaureline, dehydrostephanine and de-... 

Dehydroaporphines have been prepared from aporphines by photo-oxidation (Castedo et al.. Heterocycles, 1981, 915 ... 

The reagent that had originally been used commonly for the oxidation of aporphines to oxoaporphines was chromium trioxide in pyridine (14-16). A recent study by Cava and co-workers of the oxidation of aporphines and dehydroaporphines has led to the development of superior methods of oxidation which may be summarized as follows (27a). 

A method for the photooxidation of dehydroaporphines in benzene solution into... 

Aerial oxidation of the dehydroaporphine (75) in the presence of an alkali catalyst produced a mixture, one component of which was the non-natural aristolactam (77). ... 

Several dehydroaporphines have been tentatively detected by t.l.c.-g.c., but have not been fully characterized. These include dehydronuciferine, " dehyd-roanonaine, dehydroroemerine, " and dehydroisoboldine. Dihydroaporheine (didehydroroemerine) has also been reported. ... 

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. ... 

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