Two Novel Triterpenoids from <i>Dysoxylum hainanense</i>

Two novel rearranged oleanane-type triterpenes, dysoxyhainanin A (<b>1</b>) possessing a unique 1,3-<i>cyclo</i>-2,3-<i>seco</i> A ring with a formamido-containing appendage and dysoxyhainanin B (<b>2</b>) featuring an unprecedented 1,2-dinor-3,10:9,10-<i>bisseco</i> skeleton, were isolated from <i>Dysoxylum hainanense</i>. Dysoxyhainanin A (<b>1</b>) exhibited significant antibacterial activity against Gram-positive bacteria.