Search

Abstract: A phytochemical investigation of Isodon leucophyllus led to the isolation of four novel ent-kauranoid dimers: bisleuconins A–D (1–4), and one known compound, rabdoloxin A (5). It was interesting that the structures of bisleuconins A (1) and B (2) were elucidated as a pair of epimeric ent-kauranoid dimers with unique linkage pattern C-16→C-17′ to connect two monomers. Bisleuconins C (3) and D (4) were two new asymmetric ent-kauranoid dimers. A possible biogenetic pathway of 1 and 2 was also proposed. [Copyright &y& Elsevier]

Abstract: Two novel diterpenoids, luanchunins A (1) and B (2), along with their precursor, kamebakaurin (3), had been isolated from the stems and leaves of Isodon rubescens var. lushanensis. Their structures were elucidated on the basis of extensive spectroscopic analyses. Compounds 1 and 2 showed potent cytotoxic activity against HL-60 with IC50 values of 4.81μM and 3.52μM, respectively. Plausible pathways for the biosynthesis of 1 and 2 were also postulated. [Copyright &y& Elsevier]

Abstract: Solvent- and catalyst-free Friedel–Crafts alkylation reactions of aromatic and heteroaromatic compounds with methyl trifluoropyruvate ( 2 ) were carried out at room temperature and finished in several minutes with good to excellent yields of the addition products (69→99%), which provided a rapid and convenient method to synthesize aryl- and heteroaryl-α-hydroxy-α-triflouromethyl acetates. [Copyright &y& Elsevier]

• A new compound Ocauxarthrol A (1) was isolated from a plateau soil-derived fungus. • Ocauxarthrol A (1) was characteristic of an unusual carbonate group. • The stereochemistry of chrysoqueen (2) was revised by a crystal X-ray analysis. • Absolute configurations of auxarthrols B (3), E (4), and H (5) were also revised. A new tetrahydroanthraquinone (TAQ), ocauxarthrol A (1), as well as six known analogs, chrysoqueen (2), auxarthrols B (3), E (4), H (5), A (6), and paradictyoarthrin A (7), were isolated from the plateau soil-derived fungus Auxarthron umbrinum SCSIO 40432. X-ray crystallographic analyses were utilized to confirm the presence of a carbonate group in ocauxarthrol A (1) and to reassign the stereochemistry for 2 – 5. None of the compounds exhibited obvious antimicrobial or enzyme inhibitory activity. [ABSTRACT FROM AUTHOR]