Natural sesquiterpenoids

Abstract

This review covers the isolation, structural determination, synthesis and chemical and microbiological transformations of natural sesquiterpenoids. The literature from January to December 2012 is reviewed, and 471 references are cited.

Sesquiterpenoids and an ergosterol from cultures of the fungus Daedaleopsis tricolor

“…All these data suggested that compound 1 was a bisabolane sesquiterpenoid containing an -lactam ring. 5 Fortunately, a single crystal X-ray diffraction experiment not only confirmed the structure of compound 1 but also determined the absolute configuration ( Figure 3). Therefore, compound 1 was established to be daedatrin A, as shown.…”

“…Their structures have been elucidated on the basis of spectroscopic methods, especially 2D NMR experiments and X-ray crystallography. A noteworthy feature of bisabolane sesquiterpenoids is the preponderance of a six-membered carbon ring, 5 and compound 4 which have been reported in this article is interesting due to the degraded carbons of the side chain. Furthermore, all compounds were evaluated for their cytotoxicities against five human cancer cell lines.…”

“…3 In particular, the triterpenoid 20(29)-lupen-3-one, was isolated from the fruiting body of D. tricolor, and also showed strong antifungal, weak antibacterial and antioxidant activities. 4 In order to search for new and active natural products from higher fungi, we investigated the chemical constitutents of cultures of D. tricolor, which led to the isolation of six new bisabolane sesquiterpenoids, including three lactams, daedatrins A-C (1-3), one nor-sesquiterpenoid, daedatrin D (4), a cadinane sesquiterpene, 12-hydroxy-α-cadinol (5), and a heptanorergosterane derivative, daedatrin G (6). Their structures have been elucidated on the basis of spectroscopic methods, especially 2D NMR experiments and X-ray crystallography.…”

Synthesis of α-Methylene-γ-lactone Structure by Cyclization of ω-Formylallylsilane in Water

“…6,7) Thus, p-toluenesulfonic acid (p-TsOH) was used as a protonic acid in tetrahydrofuran (THF)/H 2 O (9 : 1) or acetone/H 2 O (9 : 1) but again, no cyclization product was afforded. Scandium and ytterbium trifluoromethanesulfonate (Sc(OTf) 3 and Yb(OTf) 3 ) are often used as Lewis acid catalysts in aqueous organic reactions. 32,33) However, the expected cyclization reaction did not occur when 1 was treated with these Lewis acids.…”

“…13 C-NMR spectra were measured at 100 MHz. The chemical shifts are reported in ppm, relative to tetramethylsilane (δ=0.0) or the central line of a triplet at 77.0 ppm for CDCl 3 . IR spectra were measured on a JASCO FT/IR-230 spectrometer.…”