EI-2128-1

EI-2128-1, a novel interleukin-1beta converting enzyme (ICE) inhibitor, was isolated from the culture broths of Penicillium sp. E-2128. EI-2128-1 selectively inhibited human recombinant ICE activity with IC50 value of 0.59 microM, without inhibiting elastase and cathepsin B. EI-2128-1 also inhibited mature interleukin-1beta secretion from THP-1 cells induced by LPS with IC50 value of 0.28 microM.

Herein, we report a concise and collective total synthesis of three natural products aranorosinol A, aranorosinol B, and EI-2128-1 and also the known penicimutanolone. A unified strategy was conceived, which divergently accessed all four congeners within 9-11 steps (LLS) from a common intermediate. Bisoxirane-directed 1,2-addition was utilized as a key step to generate the desired configuration of the C8 stereocenter of aranorosinol A and B, 28 years after their first isolation, and these were both assigned as S configurations, while the C4' and C6' configurations of EI-2128-1 were both determined to be R,R-configurations.