Thalifoline from

Some families like the Cactaceae, Chenopodiaceae and Fabaceae are known to produce simple isoquinoline alkaloids. In the Menispermaceae they are very rare. Up to the moment, the only compounds of this type isolated from plants of this family were coiypalline and thalflavine from Menispermum dcnmcum, thalifoline from Abutapahni and 6,7-dimethoxy-2-methylisoquinolone from Stephania sasakii. 

Simple isoquinolines are not found in the Menispermaceae of South America. The isoquinolone thalifoline (1) was identified from Abuta pahni [32], Benzyltetrahydroisoquinolines are the biogenetic precursors for aporphines, proaporphines, and oxoaporphines. Yet the only such compound isolated from South American Menispermaceae is (+) coclaurine (2) obtained from Sciadotema eichleriam [52] and Caryomene olivascens [37-38]. The chemistry of simple isoquinolines [65], isoquinolones [66], and benzyltetrahydroisoquinolines [67] have been reviewed. 

New, simple isoquinoline alkaloids isolated and assigned structures during the period under review include thalactamine (I), thalifoline (N-methyl derivative of 2 R = Me, R = H), and noroxyhydrastinine (2 RR = CH2), from Thalic-trum minus, and bases of general structure (3) listed in Table 1 have been identified in Peyote. ... 

No biogenetic details of simple isoquinolone were elucidated, but it is likely to yield the isoquinolones from the oxidation of benzylisoquinolines. There are a few isoquinolones in the Annonaceae. Only three simple isoquinolones, doryphomine (A-7), cherianoine (A-8) and thalifoline (A-9), were isolated from the stems of A cherimola [14,15]. 

The Pschorr reaction was described in connection with the synthesis of the papaverine (3) derivatives (350, 351). The synthesis of petaline (5b) was accomplished (352, 353). Escholamine (4a) and takatonine (4c) were synthesized by a modified Pomeranz-Fritsch reaction (354). The phenolic oxidation of (f )-(-)-N-methylcoclaurine (7c) and (S)-(+)-reticuline (7f) with peroxidase proved to be a failure (355). The oxidation of reticuline with ferricyanide yielded isoboldine (24c) and pallidine (43b) and the byproducts vanillin and thalifoline (2c) (355). A new synthesis of 3-oxo-papaverine was developed (356), and the Eschweiler-Clark method for the synthesis of codamine (7r) was modified (357). Oxidation of reticuline (7f) by enzymatic systems from homogenized P. rhoeas in the presence of hydrogen peroxide gave ( )-/3-hydroxyreticuline (10) (358). 

Isoqoinolones.—Known isoquinolones obtained from natural sources are N-methylcorydaldine (24), thalifoline (25), noroxyhydrastinine (26), N-methyl-thalidaldine (27), thalflavine (28), N-methyl-6,7-dimethoxyisoquinolone (29), doryanine (30), and thalactamine (31). A general preparation of 6,7-dioxygenated... 

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