Apoptolidins E and F, new glycosylated macrolactones isolated from Nocardiopsis sp

Two new glycosylated macrolactones, apoptolidins E (5) and F (6), were isolated from fermentation of the actinomycete Nocardiopsis sp. and their structures assigned. Lacking the C16 and C20 oxygens of apoptolidin A (1), these macrolides are also the first members of this family to display a 4-O-methyl-l-rhamnose at C9 rather than a 6-deoxy-4-O-methyl-l-glucose.

An approach to the site-selective diversification of apoptolidin A with peptide-based catalysts

We report the application of peptide-based catalysts to the site-selective modification of apoptolidin A (1), an agent that displays remarkable selectivity for inducing apoptosis in E1A-transformed cell lines. Key to the approach was the development of an assay suitable for the screening of dozens of catalysts in parallel reactions that could be conducted using only microgram quantities of the starting material. Employing this assay, catalysts (e.g., 11 and ent-11) were identified that afforded unique product distributions, distinct from the product mixtures produced when a simple catalyst (N,N-dimethyl-4-aminopyridine (10)) was employed. Preparative reactions were then carried out with the preferred catalysts so that unique, homogeneous apoptolidin analogues could be isolated and characterized. From these studies, three new apoptolidin analogues were obtained (12-14), each differing from the other in either the location of acyl group substituents or the number of acetate groups appended to the natural product scaffold. Biological evaluation of the new apoptolidin analogues was then conducted using growth inhibition assays based on the H292 human lung carcinoma cell line. The new analogues exhibited activities comparable to apoptolidin A.

Synthesis of the C1-C12 fragment of the tedanolides. Aldol-non-aldol aldol approach

The combination of highly stereoselective non-aldol aldol and aldol processes allows the preparation of the completely protected C1-C12 fragment 2 of the novel macrocyclic cytotoxic agent tedanolide 1.