Mollamide

Carroll, A.R. Bowden, B.F. Coll, J.C. Hockless, D.C.R. Skelton, B.W. White, A.H. (1994) Mollamide, a cytotoxic cyclic heptapeptide from the compound ascidian Didemnum molle. Aust. J. Chem., 47,61-69. 

A number of cyclic peptides have been isolated from the tunicate Didemnum molle. The structure of mollamide (59), a cytotoxic heptapeptide isolated from Didemnum molle from the Great Barrier Reef, was determined by X-ray crystallography and chemical degradation [88]. Mollamide has also been synthesised [89]. 

Another tunicate, Didemnum molle, has been shown to contain a novel series of cyclic peptides. They include the hexapeptides comoramides A (391) and B (392) [301] and the heptapeptides, mollamide (393) [302], cyclodidemnamide (394) [303], and mayotamides A (395) and B (396) [301]. The structures of these compounds were elucidated from spectral data, degradation experiments and, in the case of mollamide (393), by X-ray analysis. The total synthesis of cyclodidemnamide led to the revision of its structure [304]. All of them exhibited cytotoxic activity and 393 also inhibited RNA synthesis [302]. 

During this time, the total synthesis of several marine sulfur-containing natural products cited in this review has been reported and they confirmed the suggested structures. This is the case of the synthesis of some sulfonoceramides (e.g. flavocristamide A (318) discussed in the sulfonic acid and their derivatives section [366], and the synthesis of the thiazole-containing compounds bistratamide D (381) [367], trunkamide (388) [368], mollamide (393) [369], dolastatin I (409) [370], and virenamide B (414) [371]. 

Mollamide C differs from keenamide A, which was isolated from the mollusk Pleurobranchus forskalii (see Chapter 23), only by the replacement of a thiazoline by a thiazole. 

McKeever, B. and Pattenden, G. (1999) Total synthesis of mollamide, a reverse prenyl substituted cytotoxic cyclic peptide from Didemnum molle. Tetrahedron Lett., 40, 9317-9320. 

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