摘要Ten previously undescribed rearranged 4,9-friedodrimane merosesquiterpenoids,desig-nated ircinrimanes A-J(1-10),were isolated from the marine sponge Ircinia sp.,collected from the South China Sea.Their structures and absolute configurations were definitively elu-cidated through a combination of spectroscopic data analysis,DP4+probability assessments,electronic circular dichroism(ECD)calculations,and Mo2(OAc)4 experiment.Compounds 1-4 contained benzene rings,with compound 1 featuring an unusual 2-carbonyl morpholin ring,while compound 2 possessed a benzoxazole ring.Compounds 5-9 comprised sesquiterpen-oid quinones with distinct amino side chains at C-20,and compound 10 incorporated an eth-oxy side chain.Notably,compounds 1-10 demonstrated an unusual rearrangement of 4,9-friedodrimane sesquiterpenes.Compounds 2,5-8 and 10 demonstrated cytotoxic activity,while compound 2 exhibited anti-inflammatory activity in zebrafish.