35481-83-5 Istanbulin A Istanbulin-A Naphtho(2,3-b)furan-2,8(4H,5H)-dione, 4a,6,7,8a,9,9a-hexahydro-9a-hydroxy-3,4a,5-trimethyl-, (4aS-(4aalpha,5alpha,8abeta,9abeta))-