Absolute configuration of fibaruretin B

Abstract

The title furanoditerpenoid, known as fibaruretin B (systematic name: 2β,3α-dihydroxy-2,3,7,8α-tetrahydropenianthic acid lactone), C20H24O7, was isolated from the roots of Arcangelisia flava. The absolute configurations at positions 2, 3, 4, 4a, 7, 9, 10a and 10b of fibaruretin B are S, R, S, R, S, S, S and S, respectively. In the crystal structure, the molecules are linked into infinite chains along the c axis by O-H⋯O hydrogen bonds and weak C-H⋯O interactions.