5′-O-demethyl-8-O-methyl-7-epi-dioncophylline a and its ‘regularly’ configurated atropisomer from Triphyophyllum peltatum

Dioncophylline A as a Growth-Retarding Agent against the Herbivorous Insect Spodoptera littoralis: Structure−Activity Relationships

“…Dioncophylline A (1) was available from previous isolation work. 7 N-Methyldioncophylline A (4) 16 and N-formyl-8-O-methyldioncophylline A (8) 17 were prepared as described elsewhere.…”

“…Within the scope of the work described here, the potential of this as yet most active naphthylisoquinoline alkaloid was further elucidated by the preparation and testing of selected analogues. Investigation of a broad series of structurally modified dioncophylline A analogues (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) revealed the free amine function to be essential for the growth inhibitory effect, whereas a modification of the OH function partially led to a distinct increase of activity. In particular, the 8-O-alkyl (especially 8-O-benzylated) derivatives (14 and 15 as well as 16-19) displayed pronounced effects.…”

“…Initially each of the studied alkaloids (1-15, 20) was tested at the same range of concentrations (25, 50, 100, 250, 500, 750 µg/g fresh wt). In a second experiment, the more active compounds (15)(16)(17)(18)(19) were studied for growth inhibitory effects under comparable conditions but employing lower concentrations of compounds (5,10,20,40,60,80, and 100 µg/g fresh wt). From the dose-response curves obtained in the experiments, the effective concentration that inhibited growth by 50% (EC 50 ) was determined from the regression-growth curve.…”

Fortschritte der Chemie organischer Naturstoffe / Progress in the Chemistry of Organic Natural Products

“…These and more than 80 further naphthylisoquinoline alkaloids (1 12,113,[856][857][858][859][860][861][862][863][864][865][866] all have in common a 4,5-dioxy-2-methylnaphthalene 24 A (see Fig_ 77) and a 1, 3-dimethyl-8-oxy-or -6,8-dioxyisoquinoline (or -di-or -tetrahydroisoquinoline) moiety B, which may additionally be equipped with stereocenters. Typically, the Dioncophyllaceae plants produce naphthylisoquinolines with (R)-configuration at C-3, always lacking an oxygen function at C-6 (like e.g.…”

β-Phenylethylamines and the isoquinoline alkaloids

“…The new alkaloids korupensamine A (12a), korupensamine B (13), korupensamine C (12b) and korupensamine D (14) have been isolated from Ancistrocladus korupensis,15 and 5'-Odemethyl-8-O-methyl-7-epi-dioncophylline A (1 5), also a new alkaloid, together with its previously known rotamer, has been isolated from Triphyophyllum peltatum. 16 The structures of the korupensamines were deduced from detailed studies of their NMR spectra, and that of korupensamine A was confirmed by an X-ray crystallographic examination of its p-bromobenzenesulfonyl ester. 'j In addition a mixture of the rotamers korupensamines A and B has been synthesized by the reductive coupling of the naphthalene (1 6) and the tetrahydroisoquinoline (17) in the presence of a palladium(r1) catalyst."…”