| Abstract: | Eight new terpenoids ( 1 – 8 ) were isolated from the bark of Jatropha neopauciflora, together with eight known compounds. The new isolates include the sesquiterpenoids (1R,2R)‐diacetoxycycloax‐4(15)‐ene ( 1 ); (1R,2R)‐dihydroxycycloax‐4(15)‐ene ( 2 ), (2R)‐δ‐cadin‐4‐ene‐2,10‐diol ( 3 ), (2R)‐δ‐cadina‐4,9‐dien‐2‐ol ( 4 ), (1R,2R)‐dihydroxyisodauc‐4‐en‐14‐ol ( 5 ) and its acetonide 6 (artifact), as well as the two triterpenoids (3β,16β)‐16‐hydroxylup‐20(29)‐en‐3‐yl (E)‐3‐(4‐hydroxyphenyl)prop‐2‐enoate ( 7 ) and (3β,16β)‐16‐hydroxyolean‐18‐en‐3‐yl (E)‐3‐(4‐hydroxyphenyl)prop‐2‐enoate ( 8 ). The structures of these compounds were established by extensive 1D‐ and 2D‐NMR spectroscopic methods, and their absolute configurations were determined by circular‐dichroism (CD) experiments, and by X‐ray crystallographic analysis (compound 7 ; Fig. 3). A plausible biosynthesis of the sesquiterpenoids 1 – 5 is proposed (Scheme), starting from (?)‐germacrene D as the common biogenetic precursor. |
