Roccella canariensis

C2SH32N4O4, Mr 488.59, cryst., mp. 320 °C, [a] -92°. A cyclic peptide from the dyer s lichens Roccella canariensis and R. vicentina. 

Bohman-Lindgren G (1972) Chemical studies on lichens. XXXIII. Roccanin, a new cyclic tetrapeptide from Roccella canariensis. Tetrahedron 28 4625-4630... 

R-/ -Phenyl-j8-alanine (102) has been reported several times as a component of natural peptides such as islanditoxin from Penicillium islandicum and roccanin from the lichen Roccella canariensis and some preliminary observations have been... 

A cyclic tetrapeptide, roccanin (17), has been isolated by Bohman-Lindgren from Roccella canariensis (22). Acid hydrolysis of (17) yielded two amino-acids, L-proline (18) and / -P-phenyl- 3-alanine (19), and quantitative amino-acid analysis confirmed that (18) and (19) were formed in equimolar amounts. Mass spectrometry and the observed chemical reactivity confirmed that (17) was a cyclic peptide. Selective reduction of (17) at the more reactive acylproline linkage by treatment with lithium... 

Bohman-Lindgren, G. Chemical Studies on Lichens XXXIII. Roccanin, a New Cyclic Tetrapeptide from Roccella canariensis. Tetrahedron 28, 4625 (1972). 

The lichens contain important amino acids similar to those in higher plants. Picroroccellin (1) and the cyclic tetrapeptide (2a or 2b), which yields L-prolin (3) and D-/5-amino-/5-phenylpropionic acid (4) on hydrolysis, have been isolated from Roccella fuciformis (L) Dc., R, canariensis Darb., and/ . vicentina Vain. 

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