Novel Cyclopropyl Compounds, Cyclopropylvirgines A to G, from the Fruiting Bodies of Amanita Virgineoides

Abstract

Abstract Seven novel compounds (1–7) along with four known compounds (8–11) were isolated from the fruiting bodies of Amanita virgineoides. The structures of 1–7 were determined by the interpretation of spectroscopic data. Compounds 1–7 were racemates, and 5–7 were separated to each enantiomer (5a, 5b, 6a, 6b, 7a and 7b). The absolute configurations of compounds 5a and 5b were determined by single-crystal X-ray diffraction analyses, and those of 6a, 6b, 7a and 7b were determined by comparison of their CD spectra with those of l-cyclopropylalanine, 5a and 5b. Although compounds 5b, 8–11 had been synthesized, they were isolated from a natural source for the first time. Compounds 6b, 8 and 11 showed significant inhibition activity against Axl and/or immune checkpoint (PD-L1, PD-L2).