Unusual Tigliane Diterpenes from Euphorbia grandicornis

Abstract

Phytochemical study of the aerial parts of Euphorbia grandicornis led to the isolation of two new tigliane diterpenes, 16-angeloyloxy-13α-isobutanoyloxy-4β,9α,20-trihydroxytiglia-1,5-diene-3,7-dione (1) and 16-angeloyloxy-13α-isobutanoyloxy-4β,9α,7β-trihydroxytiglia-1,5-dien-3-one (2). The structures and relative configuration of the new compounds were elucidated on the basis of extensive spectroscopic analysis, including 1D and 2D NMR experiments ((1)H NMR, JMOD, (1)H-(1)H COSY, NOESY, HSQC, and HMBC), mass spectrometry, and comparison with literature data. The biogenesis of 1 and 2 with respect to the unusual 5-en-7-one and 5-en-7-ol moieties is also discussed.

Photosynthetic terpene hydrocarbon production for fuels and chemicals

“…However, most of the model high‐terpene plants (e.g. peppermint, Copaifera langsdorffii , and Euphorbia ) are C 3 plants (Croteau et al ., ; Forgo et al ., ; Groeneveld, ; Lange and Croteau, ,b; Piazza and Holzwarth, ; Rodrigues and Machado, ). Calvin cycle is mainly localized in bundle sheath cells of C 4 plants, whereas the mesophyll cells contain phosphoenolpyruvate carboxylase, the primary carboxylase of the C 4 pathway and the initial step leading to CO 2 concentrate at the site of Rubisco in bundle sheath cells.…”

“…However, most of the model high-terpene plants (e.g. peppermint, Copaifera langsdorffii, and Euphorbia) are C 3 plants (Croteau et al, 1971;Forgo et al, 2011;Groeneveld, 1987;Lange and Croteau, 1999a,b;Piazza and Holzwarth, 1989;Rodrigues and Machado, 2009). Calvin cycle is mainly localized in Figure 1 The schematic for photosynthetic terpene productions in cyanobacteria, green algae or plants.…”

Diterpenes from European Euphorbia Species Serving as Prototypes for Natural‐Product‐Based Drug Discovery

“…E. grandicornis is a succulent, cactiform plant native to southern Africa. We isolated two new tigliane diterpenes, compounds 64 and 65 (Figure 10), from the aerial parts 90. The structures of 64 and 65 differ from those of all previously known phorbol derivatives, because a 5‐en‐7‐one or 5‐en‐7‐ol functionality is present in the molecule instead of the usual 6,7‐olefin group.…”

New Cytotoxic Tigliane Diterpenoids from Croton caudatus

“…The proposed relative stereochemistry of 1 was supported by the rotating-frame nuclear Overhauser effect spectroscopy (ROESY) correlations. Starting from H-10, which was arbitrarily assigned an α-orientation, ROESY correlations between δ To the best of our knowledge, all of the tiglianetype diterpenoids discovered to date possess H-10α, OH-4β, and 13α-substituent, and the chemical shifts of compound 1 were in good agreement with those of related compounds [25,26]. Therefore, 1 was elucidated as (rel.…”