NSC293826 Naphtho[1,2-b]furan-2,8(3H,4H)-dione, 7-chloro-3a,5,5a,9,9a,9b-hexahydro-3,5a,9-trimethyl-, (3.alpha.,3a.alpha.,5a.beta.,9.alpha.,9a.alpha.,9b.beta.)-