Clerodane diterpenes structure

Phytochemical studies of these species led to the isolation and structural characterization, by NMR and MS analysis, of many secondary metabolites, mainly flavonoids, and expecially flavonol glycosides, clerodane diterpenes, and triterpenes having the lupane, ursane, and oleanane skeletons. Particularly flavonoids and their glycosides have a chemotaxonomic interest in the genus and in general in the Chrysobalanaceae family. 

Fig (70). Structure of an spasmolytic clerodane-diterpene isolated from Baccharis genistelloides... 

H. Itokawa, N. Totsuka, K. Takeya, K. Watanabe and E. Obata, "Antitumor Principles from Casearia sylvestris Sw. (Flacourtiaceae), Structure Elucidation of New Clerodane Diterpenes by 2-D NMR Spectroscopy", Chem. Pharm. Bull., 1988,56, 1585 - 1588. 

H. Morita, M. Nakayama, H. Kojima, K. Takeya, H. Itokawa, E. P. Schenkel and M. Motidome, "Structures and Cytotoxic Activity Relationship of Casearins, New Clerodane Diterpenes from Casearia sylvestris Sw. ", Chem. Pharm. Bull., 1991, 39, 693 - 697. 

The structures of all these compounds were established by spectral data including 2D NMR techniques. X-ray analysis were performed for compounds 60 (alysine A) and 139 (alysine B) in order to be sure of their stereochemistry. All six compounds had typical substitutions of neo-clerodane diterpenes, only instead of a monosubstituted fiiran, they all have a, P-disubstituted furan ring, which was the first isolation of such type of compounds. 

L6pez-01guin J., De la Torre M.C., Ortego F., Castanera P., Rodriguez B. Structure-activity relationship of natural and synthetic neo-clerodane diterpenes from Teucrium against Colorado potato beetle larvae. Phytochemistry, 50 749-753 (1999). 

Figure 60. Structures of clerodane diterpenes (included in Table 14 compilation of H-NMR data) that are derivatives of the natural products listed in Table 2.

Figure 61. Structures of clerodane diterpenes included in the compilation of C-NMR data (Table 15).

Angeles, E., K. Folting, P.A. Grieco, J.C. Huffman, R. Miranda, and M. Salmon Isolation and structure of stephalic acid, a new clerodane diterpene from Stevia polycephala, Phytochem. 21, 1804 (1982). 

Recent investigations 1 2) of the hallucinogenic Mexican mint Salvia divinorum have resulted in the isolation of the phannacologically active diterpene salvinorin (divinorin) A (1) and its desacetyl analog salvinorin B (2). Extensive H and l C NMR studies on these /raz/.s-clerodanes and their derivatives, ) as well as single-crystal X-ray analysis, have led to the fonnulation of the structures of these compounds. The absolute chemistry of the salvinorins was postulated based on the observed negative n jc Cotton effect of the 1-ketone around 295 nm in their circular dichroism (CD) spectra. 1 2)... 

Chettaphanin-1 (28), from Adenochlaena siamensis (Euphorbiaceae), represents an interesting intermediate stage in the formation of the clerodane skeleton in which C-10 but not C-4 methyl migration has occurred. The structure of this diterpene was based on dehydrogenation of the corresponding tetra-ol to 1,2,5-trimethylnaphthalene and formation of a trienone (29) by dehydration and dehydrogenation. 

C22H32O7, Mr 408.49, prisms, mp. 203.5 °C. Diterpene with clerodane structure from Croton eleuteria. 

C20H22O6, Mr 358.39, very bitter needles, insoluble in water, soluble in acetone, mp. 195-196°C, [a]u +52.7° (pyridine). Diterpene with clerodane structure from Colombo root Jateorhiza palmata), and Tino-spora cordifolia. 

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