Chapter 8 The Monoterpene Alkaloids

Cordell, Geoffrey A.

doi:10.1016/s1876-0813(08)60075-5

Cited by 7 publications

(4 citation statements)

References 116 publications

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“…Phenanthrene alkaloids are derivatives of phenanthrene with a 1-(2-aminoethyl) side chain. They are a very rare type also known as “seco-aporphine” alkaloids, probably formed biogenetically from an aporphine precursor through opening of ring B [29]. Phenanthrene alkaloids have been reported to exhibit antimicrobial activity, cytotoxicity, and dopamine receptor stimulation effects [27,30,31].…”

Section: Resultsmentioning

confidence: 99%

Antiplasmodial Alkaloids from the Bark of Cryptocarya nigra (Lauraceae)

et al. 2013

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Abstract:A dichloromethane extract of the stem bark of Cryptocarya nigra showed strong in vitro inhibition of Plasmodium falciparum growth, with an IC 50 value of 2.82 μg/mL. The phytochemical study of this extract has led to the isolation and characterization of four known alkaloids: (+)-N-methylisococlaurine (1), atherosperminine (2), 2-hydroxyathersperminine (3), and noratherosperminine (4). Structural elucidation of all alkaloids was accomplished by means of high field 1D-and 2D-NMR, IR, UV and LCMS spectral data. The isolated extract constituents (+)-N-methylisococlaurine (1), atherosperminine (2) and 2-hydroxy-atherosperminine (3) showed strong antiplasmodial activity, with IC 50 values of 5.40, 5.80 and 0.75 μM, respectively. In addition, (+)-N-methylisocolaurine (1) and atherosperminine (2) showed high antioxidant activity in a DPPH assay with IC 50 values of 29.56 ug/mL and 54.53 ug/mL respectively. Compounds 1 and 2 also both showed high antioxidant activity in the FRAP assay, with percentages of 78.54 and 70.66 respectively and in the metal chelating assay, with IC 50 values of 50.08 ug/mL and 42.87 ug/mL, respectively.

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Section: Resultsmentioning

confidence: 99%

Antiplasmodial Alkaloids from the Bark of Cryptocarya nigra (Lauraceae)

et al. 2013

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“…Conversion of 8- epi -Loganin (11) to 8- epi -Cantleyine (12) (Eq 1). One of the more common PMTAs isolated from plants, or produced as an artifact, has been cantleyine, , which is derived from the iridoid loganin. On the other hand, 8- epi -cantleyine ( 12 ) has never been reported.…”

Section: Resultsmentioning

confidence: 99%

“…Pyridine monoterpene alkaloids, PMTAs, occur naturally in a number of different plant families and genera. , They have often been prepared by semisynthesis from iridoid or secoiridoid glucosides in what are presumed to be biomimetic reactions. These reactions, of which there are many variants, generally involve treatment of the iridoid glucoside with some source of NH 3 and acid and/or a similar reaction on the aglycone formed after treatment with β-glucosidase.…”

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confidence: 99%

Pyridine Monoterpene Alkaloid Formation from Iridoid Glycosides. A Novel PMTA Dimer from Geniposide

Frederiksen

Stermitz

1996

J. Nat. Prod.

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New pyridine monoterpene alkaloids (PMTAs) have been synthesized from the iridoid glycosides 8-epi-loganin, cornin, and antirrinoside by treatment with beta-glucosidase and aqueous NH4-OAc. The PMTA from antirrinoside contained an 8-alpha-OAc group from the opened 7,8-epoxide moiety. Treatment of genipin, the aglycone of geniposide, with HCl(g) and NH3(g) yielded the PMTA racemigerine, a known plant isolate, in which the C=C-CH2OH side chain was converted to C=C-CH3. Reaction of geniposide with beta-glucosidase and aqueous NH4OAc led to oligomeric alkaloids, but at high dilution a dimer was obtained whose structure was formally that of a Diels-Alder adduct between racemigerine and a dihydropyridine. These biomimetic semisyntheses were analyzed in terms of reaction mechanisms and the relative paucity of known plant PMTAs in comparison with the multitudinous occurrence of their presumed iridoid glycoside precursors.

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“…Monoterpene alkaloids comprise several hundred members (see Figure 1B for representative examples), and are typically produced by plants, not bacteria. 9 Originating from the iridoid-loganin biosynthetic pathway, all family members harbor a distinctive 5,6-fused bicyclic ring system with piperidine (see [4][5][6][7][8][9][10] or pyridine (see 11) heterocycles. Many possess desaturation patterns similar to those of 1-3, including dinklageine (4), nepetalactam (5), and lindenialine (6), and varying stereochemistry patterns are noted at the 5,6 ring fusion (see protons in red, Figure 1B).…”

Section: ■ Introductionmentioning

confidence: 99%

Total Synthesis of Altemicidin: A Surprise Ending for a Monoterpene Alkaloid

Harmange Magnani,

Hernández-Meléndez,

Tantillo

et al. 2023

JACS Au

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Monoterpene alkaloids encompass distinct chemical diversity and wide-ranging bioactivity. Their compact complexity has made them popular as synthetic targets and has inspired many distinct strategies and tactics in the field of heterocyclic chemistry. This article documents the evolution of a synthetic program aimed at accessing the unusual sulfonamidecontaining natural product altemicidin, which was generally believed to be a monoterpene alkaloid throughout our entire synthetic investigations but has recently been found to originate through an unexpected and quite disparate biosynthetic pathway. By leveraging a pyridine dearomatization/cycloaddition strategy, we developed a concise pathway to the 5,6-fused bicyclic azaindane core and, after significant experimentation, an ultimate synthesis of altemicidin itself. Tactics to productively manipulate the multiple functional groups present on this highly polar scaffold proved challenging but were eventually realized via several carefully orchestrated and chemoselective transformations−investments that paid dividends in the form of significantly shorter chemical synthesis. Surprisingly, the bond-forming logic between our presumed abiotic synthetic strategy to this alkaloid class and its subsequently identified biosynthetic pathway is eerily similar.

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Chapter 8 The Monoterpene Alkaloids

Cited by 7 publications

References 116 publications

Antiplasmodial Alkaloids from the Bark of Cryptocarya nigra (Lauraceae)

Antiplasmodial Alkaloids from the Bark of Cryptocarya nigra (Lauraceae)

Pyridine Monoterpene Alkaloid Formation from Iridoid Glycosides. A Novel PMTA Dimer from Geniposide

Total Synthesis of Altemicidin: A Surprise Ending for a Monoterpene Alkaloid

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