Schmitz F J, Gunasekera S P, Lakshmi V, Tillekeratne L M
J Nat Prod. 1985 Jan-Feb;48(1):47-53. doi: 10.1021/np50037a008.
Two pyrrololactams, likely degradation products of more complex known guanidines, were isolated from several marine sponges. 5-Bromo- and 4,5-dibromopyrrole-1-carboxylic acid methyl esters were also isolated. A complex guanidine metabolite, poorly soluble in DMSO, was found to give sharp, reproducible nmr spectra in acid media.
