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

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).