Bromophenol coupled with diketopiperazine from marine red alga Symphyocladia latiuscula

2-(2,3,6-Tribromo-4,5-dihydroxybenzyl)hexahydropyrrolo[1,2-a]pyrazine-1,4-dione (1), a new bromophenol C-N coupled with diketopiperazine, was isolated from the ethanol extract of marine red alga Symphyocladia latiuscula. Its structure was elucidated by spectroscopic analysis, including high-resolution mass spectroscopy and 1 and 2-dimensional NMR techniques. The absolute configuration of 1 was assigned using Marfey's method on its acid hydrolysate.