Anomoian A [1], a new bromotyrosine-derived metabolite, has been isolated from the Verongid sponge Anomoianthella popeue, belonging to a new genus of the family Ianthellidae. Metabolites derived from brominated or chlorinated tyrosine are distinct markers for marine sponges belonging to the order Verongida (1). Examples of these unusual secondary metabolites are aerothionin (2), fistularin 3 (5), psammaplysin A (6,7), and bastadin 1 (8). We have recently isolated aerothionin, homoaerothionin, and the new metabolites ceratinin A and ceratinin B from the verongid sponge Pseudoceatina durisimma (9). In a continuation of our investigation of sponges of the order Verongida, we now report the isolation of a new metabolite from Anomoianthella popeue Bergquist, which belongs to a new genus established within the family Ianthellidae (10). Interest in A. popeue was stimulated by the potent in vitro antimicrobial and antifungal activity shown by the MeOH extract. The crude extract was separated from inactive material on Sephadex LH-20 followed by Si gel to give the new compound anomoian A [1] as a colorless, amorphous solid, [α]D +5.1°, that exhibited strong antimicrobial activity. Although anomoian A [1] showed a molecular ion cluster centered at m/z = 730, the peaks were too small (<2%) to obtain a high resolution mass spectrum. The molecular formula C24H31N3Br4O3·HCl for 1 was therefore obtained from the low resolution mass spectrum and the 13C-nmr spectrum (24 carbons). The ir spectrum of 1 had bands characteristic of amine (3350 cm-1) and amide (1645 cm-1) groups, while the uv spectrum showed absorptions characteristic of a substituted aryl ring [λ max 245 (ε 12,300), 276 (9400), and 285 (7800) nm]. The 1H-nmr spectrum of 1 contained signals at δ 7.46 (br s, 2H) and 7.41 (br s, 2H) that were assigned to two 1,2,4,6-tetrasubstituted aryl rings. A COSY spectrum showed coupling of the δ 7.41 signal to signals at δ 3.07 (br dd, 1H, J=13,6 Hz) and 2.95 (br dd, 1H, J=13,9 Hz). Mutual coupling between the signals at δ 3.07 and 2.95 and coupling to an additional signal at δ 3.70 (dd, 1H, J=9,6 Hz) indicated the presence of an Ar-CH2-CHX-N system. The 1H-nmr spectrum also contained signals assigned to an Ar-CH2CH2-X system. Thus, the signal due to the benzylic protons [δ 3.01 (m, 2H)] was correlated with a signal at δ 3.20 (m, 2H), and it exhibited a long range correlation to the signal assigned to the aromatic protons of the other 1,2,4,6-tetrasubstituted aryl ring [δ 7.46 (br s, 2H)]. A D2O exchangeable proton [δ 7.52 (t, 1H, J=6 Hz)], assigned to an amide NH proton, had a correlation in the COSY spectrum to a signal at δ 3.53 (m, 2H). The latter signal was also coupled to signals at δ 1.90 (m, 1H) and 1.85 (m, 1H) which in turn showed further coupling to a signal at δ 3.99 (m, 2H). These data required the presence of an RNH-CH2-CH2-CH2-O- system. A two-dimensional 13C-1H-nmr chemical shift correlation experiment (11) enabled the complete assignment of all protonated carbons (Table 1). Furthermore, the results of a long-range 13C-1H-nmr correlation experiment (COLOC) (12) established the structure 1 which was confirmed by comparison of the 13C-nmr spectrum of 1 with that of psammaplysin A [27] (Table 2). Psammaplysin A [27] and 1 have identical partial structures between C-8 and C-16, and the 13C-nmr spectra of these carbons show excellent correlation. Anomoian A was obtained both as a hydrochloride salt of a tertiary amine and as the corresponding free base. As with aplysamine 2 [31] (13), treatment of 1 in CD3OD with aqueous NaOH resulted in the formation of the free base. The N,N-dimethyl resonance in the free base was shifted upfield (δ -0.58) as was the signal of the α-methylene protons (δ -0.80); the N-methyl resonance shifted only slightly (δ -0.15). Treatment of the free base with aqueous HCl reversed the chemical shift differences and regenerated the natural product. Thus anomoian A is the hydrochloride salt of a tertiary amine and was assigned the structure 1. Anomoian A [1] inhibited the growth of Staphylococcus aureus at 10 μg/disk, Bacillus subtilis at 5 μg/disk, and Candida albicans at 25 μg/disk in in vitro antimicrobial assays. Anomoian A bears some relationship to aplysamine 2 [31], a cytotoxic metabolite of the Australian verongid sponge, Aplysia sp. (13).