Hyrtiosins A-E, five new scalarane sesterterpenes from the south China sea sponge Hyrtios erecta

Five new scalarane sesterterpenes, hyrtiosins A-E (1-5), together with three previously reported sesterterpenes, 25-dehydroxy-12-epi-scalarin (6), 12-epi-scalarin (7) and heteronemin (9), were isolated from the South China Sea sponge 11 Hyrtios erecta. Their structures were determined on the basis of extensive NMR studies and high-resolution MS measurements.