Three Sulfur-Containing Natural Products From Rubus Hirsutus Thunb

Abstract

Chemical investigation of the leaves and stems of Rubus hirsutus Thunb has resulted in the isolation and characterization of a rare new tricyclic thienocyclopentapyran (1) and 2 known thiophenes, 5-(3-buten-1-ynul)−2,2’-bithiophene (2) and α-terthienyl (3). The structure of compound 1 was unambiguously determined by nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry and time-dependent density functional theory electronic circular dichroism calculations. The new compound 1 exhibited impressive antibiotic properties against methicillin resistant Staphylococcus aureus (MRSA), with an MIC value of around 1 µg/mL.