It should also be appreciated that the C3, C4 double bond may be epoxidized; that the C6 methyl group may be replaced with ???CH2OH or ???CH2OMe; that the C43 hydroxy may be converted to F, Cl or H or other substituent; and that the C42 methoxy moiety may be demethylated, in any of the compounds disclosed herein, using methods known in the art.