Cliona celata Celenamides

Two brominated linear peptides that are found in the sponge Cliona celata, celenamide A (21 R = CH2CHMe2) and celenamide B (21 R = CHMe2), bear close structural relationships to the cyclic peptides integerrin and lasiodine A that occur in plants.16 A I3C n.m.r. analysis of cyclic peptide alkaloids has been reported and the chemical shifts of most of the carbon atoms in discarines A and B, lasiodines A and B, pandamine, pandaminine, and hymenocardine have been assigned.17... 

Stonard, R.J., and RJ. Andersen Linear Peptide Alkaloids from the Sponge Cliona celata (Grant). Celenamides C and D. Can. J. Chem., 58, 2121 (1980). 

Cliona celata has furnished a series of linear peptide alkaloids, the celenamides A to D (278-281), in addition to the previously known clionamide (282) (168, 169). These compounds were isolated in the form of their polyacetates after acetylation of the methanolic extract of the homogenized sponge. The celenamides contain a unique amino acid a,P-didehydro-3,4,5-trihydroxyphenylalanine, as a subunit. The configuration of the double bond in the dehydroamino acid residue has been determined by synthesis of the hexa-acetate of 278 (170). 

Stonard, R.J. and Andersen, R.J. (1980a) Celenamides A and B, linear peptide alkaloids from the sponge Cliona celata. J. Org. Chem., 45, 3687-3691. 

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