1,2-Dihydro-alpha-santonin 1,2-Dihydrosantonin 18409-93-3 42807-12-5 Naphtho(1,2-b)furan-2,8(3H,4H)-dione, 3a,5,5a,6,7,9b-hexahydro-3,5a,9-trimethyl-, (3S-(3alpha,3aalpha,5abeta,9bbeta))-