Isochromophilones I and II, novel inhibitors against gp120-CD4 binding produced by Penicillium multicolor FO-2338. II. Structure elucidation.

The structures of isochromophilones I and II, new gp120-CD4 binding inhibitors isolated from a cultured broth of Penicillium multicolor FO-2338, were elucidated by NMR experiments. Both of compounds have an azaphilone skeleton substituted by a chlorine atom at C-5 and a side chain, 3,5-dimethyl-1,3-heptadien at C-3. Additionally, isochromophilone I has a gamma-lactone ring, and isochromophilone II has 2-oxopropyl moiety instead of a gamma-lactone ring.