F152 (LL-Z1640-2) (1) is a zearalenone-like macrolide, isolated from shake flask fermentation, crude extracts of which inhibited the ciliated protozoan Tetrahymena pyriformis (see, McGahren et al. J. Org. Chem. 1978, 43, 2339). It was reported that initial biological studies using this natural product failed to yield any particularly interesting activities.

After initial isolation and reporting of this compound, several other groups explored the possibility of preparing additional derivatives and/or further exploring their biological activity. For example, scientists at Merck reported that F152 and certain isomers thereof inhibit the phosphorylating enzyme Map/Erk kinase (MEK) and thus are useful for the treatment of certain cancers and other diseases characterized by the formation of neoangiogenesis (see, GB 323 845). Other groups have also reported derivatives of F152 having activity as tyrosine kinase inhibitors, which are useful, for example, for the treatment of cancer and inflammatory disorders (see, EP 606 044; WO 00/38674; JP 8-40893; WO 96/13259; U.S. Pat. Nos. 5,728,726; 5,674,892; 5,795,910). Each of these groups, however, was only able to obtain F152 and derivatives thereof by fermentation techniques and by modifications to the natural product, respectively, and thus were limited in the number and types of derivatives that could be prepared and evaluated for biological activity. Additionally, although F152 and certain derivatives thereof have demonstrated potent in vitro activities, these compounds are biologically unstable (for example, they are susceptible to enone isomerization in mouse and human plasma), thereby limiting the development of these compounds as therapeutics for the treatment of humans or other animals.
Clearly, there remains a need to develop synthetic methodologies to access and examine the therapeutic effect of a variety of novel analogues of F152, particularly those that are inaccessible by making modifications to the natural product. It would also be of particular interest to develop novel compounds that exhibit a favorable therapeutic profile in vivo (e.g., are safe and effective, while retaining stability in biological media).