Methylplatydesminium salts

Platydesmine (5 R = H), the biosynthetic precursor of dictamnine and other furoquinoline alkaloids, has been detected for the first time in a Haplophyllum species H. perforatum).5 Choisya ternata is known to contain O-methyl-balfourodinium salt (4 R = OMe), but now AT-methylplatydesminium salt (4 R = H) has been isolated in equal amount to (4 R = OMe) from the stalks and roots (4 R = OMe) is the predominant quaternary alkaloid of the leaves.3... 

The major alkaloid of Araliopsis tabouensis is (+)-N-methylplatydesminium salt (see Vol. 6), and a study of the minor constituents has now resulted in the isolation of (+)-isoplatydesmine (2) and the pyranoquinolone (+)-ribalinine (folifine) (3).2... 

Pteleatinium salt Methylplatydesminium salt. Methylhydroxyluninium salt Ptelea Cholsya Cholsya ... 

Platydesmine, N-Methylplatydesminium Salt, Isoplatydesmine, Arali-opsine, and Edulinine... 

The alkaloid edulinine was first obtained from Casimiroa edulis Llave and Lex., and it was assigned the diol structure 54 on the basis of NMR and mass spectra (17). An optical rotation was not recorded, but the alkaloid from this source was later described as being optically active, [a]D-15° (47). The constitution was confirmed by comparison with ( )-edulinine obtained from synthetic Af-methylplatydesminium iodide by treatment with aqueous ammonia at 20° (37) and with (-)-edulinine, [a]D-20° (CHC13), resulting from a similar reaction on (+)-7V-methylplatydesminium salt (37). The alkaloid has been obtained from a number of other sources ... 

Edulinine from Casimiroa edulis may be formed from (+)-N-methylplatydesminium salt during isolation. (+)-Edulinine from Pelea barbigera is certainly an artifact, and was obtained only when base was employed during isolation the precursor, presumably (—)-JV-methyl-platydesminium salt, could not be detected (43). ( )-Edulinine is conveniently prepared by reaction of 4-methoxy-l-methyl-3-(3-methylbut-2-enyl)-2-quinolone with m-chloroperbenzoic acid and then with aqueous base, without isolating intermediates (2). 

The existence of furoquinoline alkaloids containing Cs isoprenyl groups elsewhere in the molecule [for example, evoxine (331) and choisyine (332)] and the cooccurrence of furoquinoline alkaloids such as dictamnine with isopropyldihydrofuroquinolines like JV-methylplatydesminium salt (326) provided convincing taxonomic evidence for the suggestion that the C2... 

Confirmation of the isoprenoid nature of the furan rings of dictamnine (328) and of N-methylplatydesminium salt (326) in S. japonica was provided indirectly by Grundon and his co-workers (224), who showed that the 3-prenylquinolones 321 and 322 labeled at - with 14C were good precursors of both alkaloids (3.6-4.8% incorporation). Specific incorporation of the precursors into dictamnine was indicated by oxidative degradation by a method similar to that used previously. N-Methylplatydesminium salt was counted as its base-cleavage product edulinine (256), which was converted into isodictamnine (Section IV,B,3) oxidation via 3-carboxy-4-hydroxy-l-methyl-2-quinolone gave 14C-labeIed carbon dioxide. 

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