TY  - JOUR
A1  - Tshitenge Tshitenge, Dieudonné
A1  - Bruhn, Torsten
A1  - Feineis, Doris
A1  - Mudogo, Virima
A1  - Kaiser, Marcel
A1  - Brun, Reto
A1  - Bringmann, Gerhard
T1  - An unusually broad series of seven cyclombandakamines, bridged dimeric naphthylisoquinoline alkaloids from the Congolese liana Ancistrocladus ealaensis
JF  - Scientific Reports
N2  - A series of seven unusual dimeric naphthylisoquinoline alkaloids was isolated from the leaves of the tropical liana Ancistrocladus ealaensis J. Léonard, named cyclombandakamine A (1), 1-epi-cyclombandakamine A (2), and cyclombandakamines A3–7 (3–7). These alkaloids have a chemically thrilling structural array consisting of a twisted dihydrofuran-cyclohexenone-isochromene system. The 1′″-epimer of 4, cyclombandakamine A1 (8), had previously been discovered in an unidentified Ancistrocladus species related to A. ealaensis. Both lianas produce the potential parent precursor, mbandakamine A (9), but only A. ealaensis synthesizes the corresponding cyclized form, along with a broad series of slightly modified analogs. The challenging isolation required, besides multi-dimensional chromatography, the use of a pentafluorophenyl stationary phase. Featuring up to six stereocenters and two types of chiral axes, their structures were elucidated by means of 1D and 2D NMR, HRESIMS, in combination with oxidative chemical degradation experiments as well as chiroptical (electronic circular dichroism spectroscopy) and quantum chemical calculations. Compared to the ‘open-chain’ parent compound 9, these dimers displayed rather moderate antiplasmodial activities.
KW  - Screening
KW  - Solution-state NMR
KW  - Stereochemistry
KW  - Structure elucidation
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200759
VL  - 9
ER  -