Dibromopyrrole Alkaloids from the Marine Sponge Acanthostylotella sp

Abstract

Fourteen dibromopyrrole alkaloids were isolated from the marine sponge Acanthostylotella sp. collected in Indonesia. In addition to the known compounds 4,5-dibromo-N-(methoxy-methyl)-1H-pyrrole-2-carboxamide (7), 4,5-dibromo-1H-pyrrole-2-carboxamide (8), mukanadin D (9), (±)-longamide B methyl ester (10), (±)-longamide B (11), (±)-longamide (12), 3,4-dibromo-1H-pyrrole-2-carboxamide (13), 2-cyano-4,5-dibromo-1H-pyrrole (14), six compounds were isolated that proved to be new natural products including acanthamides AD (1-4), methyl 3,4-dibromo-1H-pyrrole-2-carboxylate (5) and 3,5-dibromo-1H-pyrrole-2-carboxylic acid (6). The structures of the new compounds were unequivocally identified based on one and two dimensional NMR and on HRFTMS as well as by comparison with the literature.

Alkaloids and polyketides from the South China Sea sponge Agelas aff. nemoechinata

“…1D NMR of compound 3 showed the typical pyrrole-2-carboxamido core and a butyric side chain containing two methylenes (d C 44.6, 40.0), one oxygenated methine (d C 66.7), and one carboxyl group (d C 171.7), as well as a methoxy (d C 51.2), indicating that compound 3 was an analogue of acanthamide A isolated from sponge Acanthostylotella sp. 16 In 2D NMR, two spin-coupling systems of H-1/H-2/H-3/H-4 and H-7/H 2 -8/H-9/H 2 -10(OH-9) evident from 1 H-1 H COSY spectrum of 3 indicated the partial structures of pyrrole core and side chain ( Table 3). The isolated aza-aromatic 1 H NMR spectrum of 8 suggested it as a purine-labdane diterpenoid alkaloid.…”

Marine natural products

“…497,498 (+)-Dihydrodiscorhabdin L 538 was isolated from Spongosorites sp. 501 (Z)-Axinohydantoin and (Z)-debromoaxinohydantoin (Stylotella aurantium) 502 have been synthesised. 496 Latrunculia (Biannulata) wellingtonesis (Wellington, New Zealand) yielded the cytotoxic (6R,8S)-1-thiomethyldiscorhabdin G*/I 539 and both enantiomers of 16a,17a-dehydrodiscorhabdin W 540.…”

“…(Bali, Indonesia). 501 (Z)-Axinohydantoin and (Z)-debromoaxinohydantoin (Stylotella aurantium) 502 have been synthesised. 503 Syntheses of ceratamines A and B (Pseudoceratina sp.)…”

Insights into Enzyme Catalysis and Thyroid Hormone Regulation of Cerebral Ketimine Reductase/μ-Crystallin Under Physiological Conditions

“…Interestingly, Pyr2C, which we show is an excellent enzyme substrate, also originates from the breakdown of collagen [11]. 4,5-Dibromopyrrole-2-carboxylate is a naturally occurring marine natural product analogue of pyrrole-2-carboxylate [44]. The dibromo compound was tested as a potential inhibitor to assess the effect of substitutions at the 4-and 5-positions in the pyrrole ring on enzyme inhibition.…”