Alkaloids from dendrobatid poison frogs: Further cis-decahydroquinolines and 8-methylindolizidines

Tokuyama, Takashi; Tsujita, Tomohiro; Shimada, Akira; Garraffo, H. Martin; Spande, Thomas F.; Daly, John W.

doi:10.1016/s0040-4020(01)80974-1

Cited by 60 publications

(62 citation statements)

References 14 publications

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“…The strong, sharp Bohlmann band at 2783 cm −1 is expected of an N -methyldecahydroquinoline and is in marked contrast to the weak Bohlmann bands of decahydroquinolines, such as cis - and trans - 243A . 9–11 …”

Section: Resultsmentioning

confidence: 99%

N-Methyldecahydroquinolines: An Unexpected Class of Alkaloids from Amazonian Poison Frogs (Dendrobatidae)

et al. 2009

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The dominant alkaloids previously identified in skin extracts of Amazonian dendrobatid frogs of the genus Ameerega are histrionicotoxins and 2,5-disubstituted decahydroquinolines. Analysis of alkaloids in skin extracts of Ameerega picta from Bolivia revealed that the alkaloid 257A, previously reported as a 2,5-disubstituted decahydroquinoline, is an N-methyl-2,5-disubstituted decahydroquinoline. We characterized alkaloids of another 12 of the more than 25 species recently assigned to the genus Ameerega, and five additional N-methyldecahydroquinolines were identified. In some cases, the relative configuration of the N-methyldecahydroquinolines was determined by comparison with the N-methylated products prepared from the corresponding 2,5-disubstituted decahydroquinolines of known relative configuration. A dietary source for N-methyldecahydroquinolines is unknown; however, myrmicine ants are the likely source for the 2,5-disubstituted decahydroquinolines. The alkaloids in skin extracts of three species of another genus of Amazonian poison frog, Adelphobates, were also characterized, but N-methyldecahydroquinolines were not detected.

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Section: Resultsmentioning

confidence: 99%

N-Methyldecahydroquinolines: An Unexpected Class of Alkaloids from Amazonian Poison Frogs (Dendrobatidae)

et al. 2009

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“…This assignment was supported by the lack of Bohlmann bands in the IR spectrum. 10 The remaining unassigned proton signals were a methyl triplet at δ 0.90 and a complex band between δ 1.10 and 1.40, representing 12 methylene protons. HMBC correlations were observed between the oxygenated methine proton at δ 3.42 and methylene carbons at δ 19.1, 26.1, 38.1, and 40.3.…”

Section: Resultsmentioning

confidence: 99%

Lepadins F−H, New cis-Decahydroquinoline Alkaloids from the Australian Ascidian Aplidium tabascum

2002

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Chemical investigation of a Great Barrier Reef ascidian, Aplidium tabascum, has resulted in the isolation of three new cis-decahydroquinoline alkaloids, lepadins F-H (4-6). The three new compounds differ from the previously isolated lepadins A-C (1-3) in that they contain a fully saturated 5-hydroxyoctyl side chain attached at C-5, an unsaturated eight-carbon ester moiety attached to C-3, and opposite stereochemistry at C-5 and C-3. Lepadins G (5) and H (6) are epimers at C-2. NMR and molecular modeling studies indicated that the three new compounds adopt a chair-chair conformation in which the nitrogen equatorially substitutes the cyclohexyl ring. This contrasts with lepadins A-C (1-3), which adopt a chair-chair conformation in which the nitrogen axially substitutes the cyclohexyl ring.

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“…Hydrogenation of the double bond in 11 or 12 over 20% Pd(OH) 2 and then treatment of the resulting deblocked amino alcohols with trimethylaluminum under Weinreb's conditions [21] gave rise to the lactams 1 and 2 in 71% and 68% overall yields, respectively. To demonstrate the utility of the chiral lactam building blocks, we conducted the total synthesis of indolizidines (-)-203A [22] and (-)-205A [23] from 1, and (-)-219F [2] from 2, respectively (Scheme 3, Scheme 4). Removal of the silyl protecting group in 1 was performed by treatment with TBAF to afford the corresponding alcohol 13, which was converted to the homologated ester 14 via a two-step oxidation, followed by an Arndt-Eistert sequence of the resulting carboxylic acid.…”

Section: Introductionmentioning

confidence: 99%

“…[27] After oxidation of 18 under the Swern conditions, treatment of the resulting aldehyde with Seyferth-Gilbert reagent in the presence of t-BuOK furnished (-)-205A, whose spectral data were identical with reported values. [22,28] In addition, (-)-219F, a 5,8-disubstituted indolizidine with an ethyl group at C-8, [2] was synthesized from 2 (Scheme 4). The lactam 2 was converted to the homologated alcohol 20 via 19 as used with 1 in the synthesis of (-)-205A, which was then transformed into (-)-219F using the Seyferth-Gilbert reaction after Swern oxidation of 20.…”

Section: Introductionmentioning

confidence: 99%

Flexible synthetic routes to poison-frog alkaloids of the 5,8-disubstituted indolizidine-class I: synthesis of common lactam chiral building blocks and application to the synthesis of (-)-203A, (-)-205A, and (-)-219F

Toyooka¹,

Zhou²,

Nemoto³

et al. 2007

Beilstein J. Org. Chem.

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Alkaloids from dendrobatid poison frogs: Further cis-decahydroquinolines and 8-methylindolizidines

Cited by 60 publications

References 14 publications

N-Methyldecahydroquinolines: An Unexpected Class of Alkaloids from Amazonian Poison Frogs (Dendrobatidae)

N-Methyldecahydroquinolines: An Unexpected Class of Alkaloids from Amazonian Poison Frogs (Dendrobatidae)

Lepadins F−H, New cis-Decahydroquinoline Alkaloids from the Australian Ascidian Aplidium tabascum

Flexible synthetic routes to poison-frog alkaloids of the 5,8-disubstituted indolizidine-class I: synthesis of common lactam chiral building blocks and application to the synthesis of (-)-203A, (-)-205A, and (-)-219F

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