Nagelamides Q and R, Novel Dimeric Bromopyrrole Alkaloids from Sponges Agelas sp.

Abstract

Two new dimeric bromopyrrole alkaloids, nagelamides Q (1) and R (2), have been isolated from Okinawan marine sponges of the genus Agelas (SS-1134 and SS-956, respectively), and the structures and stereochemistry were elucidated from spectroscopic data. Nagelamide Q (1) is a rare dimeric bromopyrrole alkaloid possessing a pyrrolidine ring, while nagelamide R (2) is the first bromopyrrole alkaloid having an oxazoline ring. Nagelamides Q (1) and R (2) showed antimicrobial activity.

Benzosceptrin C, a new dimeric bromopyrrole alkaloid from sponge Agelas sp.

“…1 During our search for bioactive substances from marine organisms, we previously isolated several bromopyrrole alkaloids with unique cyclic skeletons from sponges of the genus Agelas. [2][3][4][5][6][7] Further investigation of extracts of an Okinawan marine sponge of the genus Agelas (SS-956) resulted in the isolation of a new dimeric bromopyrrole alkaloid, benzosceptrin C (1). Herein we describe the isolation and structure elucidation of 1.…”

“…(SS-956) collected off Unten-Port, Okinawa, was extracted with MeOH. n-BuOH-soluble materials of the extract were subjected to silica gel and C 18 columns followed by C 18 HPLC to yield benzosceptrin C (1, 0.00036% wet weight) as a colorless amorphous solid together with known related alkaloids, oroidin, 8,9 ageliferin, 10,11 mauritiamine, 12 and nagelamides B, 2 C, 2 L 4 , and R. 7 Benzosceptrin C (1) {½a 20 D À5 (c 0.5, MeOH)} showed the pseudomolecular ion peaks at m/z 771, 773, 775, 777, and 779 (1:4:6:4:1) in the ESIMS, indicating the presence of four bromine atoms, and the molecular formula of 1 was revealed to be C 22 H 18 N 10 O 2 79 Br 4 by HRESIMS data [m/z 770.8419 (M+H) + , D À0.7 mmu]. The UV absorption [k max 275 nm (e 16,600)] was attributed to a substituted pyrrole chromophore, 2 while IR absorptions indicated the existence of amino (3414 cm À1 ) and amide carbonyl (1645 cm À1 ) functionalities.…”

Bromopyrrole alkaloids from the caribbean sponge Agelas cerebrum

“…The UV absorption [λ max 273 nm (log ε 4.10)] was attributed to a substituted pyrrole chromophore. 13 The bands at 3356, 3122, and 1649 cm −1 in the IR spectrum suggested the presence of amine and carbonyl moieties. In the 14 On this basis, compound 1 was concluded to be 5-bromopyrrole-2-carboxylic acid.…”

“…In the 14 On this basis, compound 1 was concluded to be 5-bromopyrrole-2-carboxylic acid. On the other hand, compounds 2-8 were identified by a combination of spectroscopic methods ( 1 H, 13 C 1D and 2D NMR, ESIMS) and comparison with the literature data.…”

Bromopyrrole Alkaloids from a Marine Sponge <i>Agelas</i> sp.

“…[2][3][4] In our continuing search for metabolites from Okinawan marine sponges, we have previously reported the isolation of a series of bromopyrrole alkaloids from Agelas spp. [5][6][7][8][9][10][11] Recently, we have also reported monomeric bromopyrrole alkaloids, nagelamides U-W, 12) and dimeric bromopyrrole alkaloids, nagelamides X-Z, 13) from the extracts of a sponge Agelas sp. (SS-162).…”