Six new guanidine compounds, named minalemines A-F-2, were isolated fr
om the marine tunicate Didemnun rodriguesi by careful HPLC separation.
Their structures were elucidated by MS, 1D- and 2D-NMR spectral analy
sis, and chemical degradation. These compounds incorporate one agmatin
e (Agma) and one homoagmatine (Hagma) terminal unit with their guanidi
ne groups free and the primary amino groups linked through a peptidic
bond to L-Leu and a very rare beta-N-carboxymethyl amino acid (Ncma) b
earing a saturated long chain. The saturated chains of minalemines A-C
are homologs (C7, C8, and C9 respectively). Minalemines D-F are the s
ulfamic acid derivatives of minalemines A-C and constitute the first e
xamples of such a functional group in a marine organism. (C) 1998 Else
vier Science Ltd. All rights reserved.