Three Pairs of New Spirocyclic Alkaloid Enantiomers From the Marine-Derived Fungus Eurotium sp. SCSIO F452.

ABSTRACT: Three pairs of new spirocyclic alkaloid enantiomers eurotinoids A-C (1-3), as well as a known biogenetically related racemate dihydrocryptoechinulin D (4) were isolated from a marine-derived fungus Eurotium sp. SCSIO F452. Their structures were determined by spectroscopic analyses and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 represent the first two "meta" products from a non-stereoselective [4 + 2] Diels-Alder cycloaddition presumably between an enone group of a diketopiperazine alkaloid and a diene group of a benzaldehyde derivative via a new head-to-tail coupling mode biosynthetically, while 3 and 4 were "ortho" products. Their enantiomers exhibited different antioxidative and cytotoxic activ

SUBMITTER: Zhong W 

PROVIDER: S-EPMC6536037 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature