Eremophilanes from Senecio mairetianus and Some Reaction Products

Abstract

Eight new eremophilanolides (1, 2, 4-7, 9, and 10), a new eremophilane (13), and several known compounds were isolated from the roots and aerial parts of Senecio mairetianus. The chemical structures were proposed taking into consideration spectroscopic analyses and chemical transformations. X-ray diffraction analysis of 2, 4, and 9 confirmed their structures. The stereochemistry of 1,10-epoxy-8alpha-methoxyermophilanolide (3) was determined. Compounds 4-7, 9, and 10 are possible artifacts obtained by preparation of the alkaloidal extract.

Eremophilane-Type Sesquiterpenes from the Fungus Xylaria sp. BCC 21097

“…Compound 6 was assigned as the 13-deoxy analogue of 4 . This compound is identical to mairetolide F, previously isolated from the higher plant Senecio mairetianus …”

Two novel eremophilane sesquiterpenes from an endophytic Xylariaceous fungus isolated from leaves of Cupressus lusitanica

“…Compounds 3 and 4 were previously reported in the literature. 16,17 Compound 1 was obtained as a colorless crystal. The IR spectrum displayed a broad band at 3487 cm -1 characteristic of a hydroxyl group and a band at 1745 cm -1 attributed to a conjugated γ-lactone.…”

A new eremophilenolactone from the roots ofSenecio ambraceus

“…The homoallylic coupling were observed between CH 3 -13 (dd, J ¼ 1.8, 1.8 Hz) with H-6 (brs) and CH 3 -13 (dd, J ¼ 1.8, 1.8 Hz) with H-8 (ddd, J ¼ 10.8, 7.2, 1.8 Hz), which suggested dihedral angles of about 90 for H-6 and H-8 with the double bond of C-7(11), thus indicating -orientation for both H-6 and H-8 (Castorena, Arciniegas, Guzman, Villaseno, & Vivar, 2006;Naya, Nogi, Makiyama, Takashina, & Imagawa, 1977;Yaoita & Kikuchi, 1995). In NOESY spectrum, the observed cross-peak between H-6 and H-8 further confirmed the angeloyloxyl group at C-6 be -orientation and the lactone be configuration at C-8.…”