Isolation, Synthesis, and Radical-Scavenging Activity of Rhodomelin A, a Ureidobromophenol from the Marine Red Alga Rhodomela confervoides.

A novel ureidobromophenol, rhodomelin A (1), was characterized from Rhodomela confervoides. Its structure was elucidated by spectroscopic analysis. Both enantiomers of 1 were synthesized using a convergent strategy starting from d/l-pyroglutamic acids, respectively, allowing assignment of the R-configuration for the naturally occurring isomer by chiral HPLC analysis.