Neoclerodane Diterpenes from Baccharis crispa

Abstract

In order to confirm the previously proposed stereochemistry for bacrispine (1), several high-field 2D NMR (500 MHz) experiments were carried out. Complete NMR assignments, as well as the validation of the relative stereochemistry of 1-deoxybacrispine (2), were established. In an investigation of the aerial parts of Baccharis crispa, a medicinal plant from Argentina, two new neoclerodanes (4, and 5) have been isolated and their structures determined by spectroscopic means.

Ten New Labdane-Type Diterpenes from the Fruit of Vitex rotundifolia.

“…The 1 H-and 13 C-NMR spectra of 1 were superimposable on those of 11 apart from the chemical shifts of signals due to the olefinic group [d 7.13 (H-14), 135.0 (C-13), 144.0 (C-14) in 1; d 5.84 (H-14), 171.1 (C-13), 115.0 (C-14) in 11], which exhibited the replacement of a b-substituted butenolide ring in 11 by an a-substituted butenolide ring. 8) Furthermore, the difference NOE spectra of 1 indicated correlations between the respective protons, as illustrated in Fig. 2.…”

“…As part of the continuing study of this fruit, we now describe the isolation and structural elucidation of ten new labdane-type diterpenes (1-10), along with a known labdane-type diterpene, vitexilactone (11) 7) from the MeOH extract. The MeOH extract of the fruit of Vitex rotundifolia L. was purified by Diaion HP-20, silica gel, Sephadex LH-20 and Chromatorex ODS column chromatography, as well as by HPLC on ODS and silica gel to afford eleven labdane-type diterpenes (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11).…”

Plant secondary metabolites from Argentinean semiarid lands: bioactivity against insects

“…Taking into account the grain production of Argentina it is an interesting insect model to use in antifeedant activity studies toward clerodane diterpenes. In this order a considerable number of this kind of compounds (23-49) has been isolated in our laboratory from plants of the Asteraceae and Labiatae families Luco et al 1994;Gallardo Varas et al 1996;Ceñ al et al 1997;Enriz et al 2000;Simirgiotis et al 2000;Cifuente et al 2002;Gonzá lez Coloma et al 2005;Juan et al 2006). From this set of diterpenes, compounds 50-55 were prepared by chemical transformations.…”

New Clerodane Diterpenes from Tinospora sagittata var. yunnanensis

“…The α-substituted butenolide ring moiety was assigned to be attached at C-12 by the HMBC correlations of H-14 with C-12, and H-12 with C-13. Comparison of the NMR data of compound 1 with those of marrubiagenine [12] and 1α,7α-dihydroxyneocleroda-3,13-dien-16,15 : 18,19-diolide [13] showed the existence of an extra glucose at C-17 in compound 1. The additional β-D-glucopyranosyl moiety linked at C-17 was further supported by the long-range HMBC correlation between H-1′ (δ H 4.22) and C-17 (δ C 72.7).…”