Synthesis of Lamellarin G Trimethyl Ether by von Miller–Plöchl‐Type Cyclocondensation

Colligs, Vanessa C.; Dialer, Clemens; Opatz, Till

doi:10.1002/ejoc.201800611

Cited by 22 publications

(14 citation statements)

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“…In 2012, a new bromopyrrole, 4-bromo-N-(butoxymethyl)-1H-pyrrole-2-carboxamide (192), featuring an unusual ether group in its side chain, could be isolated from the marine sponge Agelas mauritiana (Figure 24) [233]. (196)(197)(198)(199).…”

Section: Simple Pyrrolesmentioning

confidence: 99%

“…A new class of bromopyrrole pigments derived from bromotyrosine were isolated from the marine ciliate Pseudokeronopsis riccii in 2010 and were named keronopsamides A-C (201-203) (Figure 25) [236]. (196)(197)(198)(199).…”

Section: Simple Pyrrolesmentioning

confidence: 99%

“…Further structurally similar halopyrroles 193-199 possessing different substituents at their amide side chains were isolated from the Indonesian marine sponges Agelas linnaei (Figure 24) [234]. While mauritamide D (193), 4-(4,5-dibromo-1-methylpyrrole-2carboxamido)-butanoic acid (194), and agelanin B (195) were inactive against L1578Y mouse lymphoma cell lines, the tyramine-unit bearing agelanesins A-D (196)(197)(198)(199) showed prominent to good activity with IC 50 values between 9.25 µM and 16.76 µM in this assay. The authors mentioned that the cytotoxicity of the agelanesins 196-199 is interconnected with the degree of bromination of the pyrrole ring, resulting in an increased reactivity for the monobrominated agelanesins A (196) and B (197) compared to 198 and 199 [234].…”

Section: Simple Pyrrolesmentioning

confidence: 99%

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Marine Pyrrole Alkaloids

2021

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Nitrogen heterocycles are essential parts of the chemical machinery of life and often reveal intriguing structures. They are not only widespread in terrestrial habitats but can also frequently be found as natural products in the marine environment. This review highlights the important class of marine pyrrole alkaloids, well-known for their diverse biological activities. A broad overview of the marine pyrrole alkaloids with a focus on their isolation, biological activities, chemical synthesis, and derivatization covering the decade from 2010 to 2020 is provided. With relevant structural subclasses categorized, this review shall provide a clear and timely synopsis of this area.

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Section: Simple Pyrrolesmentioning

confidence: 99%

Section: Simple Pyrrolesmentioning

confidence: 99%

Section: Simple Pyrrolesmentioning

confidence: 99%

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Marine Pyrrole Alkaloids

2021

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Section: Heterocyclic Marine Drugs With Effect On Tumor Cell Prolimentioning

confidence: 99%

“…The first one includes the functionalization of the pyrrole moiety, and the second one consists of employing the appropriate acyclic precursor to synthesize the pyrrole. Due to its biological activity, many groups have devoted their time to develop methods for its synthesis [107][108][109][110] as well as the synthesis of other members of the family [111][112][113][114]. More recently, Michael and coworkers have published the synthesis of lamellarin D trimethyl ether 162 by using enaminones as intermediates to alkaloids and other nitrogen heterocycles [117].…”

Section: Lamellarinsmentioning

confidence: 99%

Marine Heterocyclic Compounds That Modulate Intracellular Calcium Signals: Chemistry and Synthesis Approaches

et al. 2021

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Intracellular Ca2+ plays a pivotal role in the control of a large series of cell functions in all types of cells, from neurotransmitter release and muscle contraction to gene expression, cell proliferation and cell death. Ca2+ is transported through specific channels and transporters in the plasma membrane and subcellular organelles such as the endoplasmic reticulum and mitochondria. Therefore, dysregulation of intracellular Ca2+ homeostasis may lead to cell dysfunction and disease. Accordingly, chemical compounds from natural origin and/or synthesis targeting directly or indirectly these channels and proteins may be of interest for the treatment of cell dysfunction and disease. In this review, we show an overview of a group of marine drugs that, from the structural point of view, contain one or various heterocyclic units in their core structure, and from the biological side, they have a direct influence on the transport of calcium in the cell. The marine compounds covered in this review are divided into three groups, which correspond with their direct biological activity, such as compounds with a direct influence in the calcium channel, compounds with a direct effect on the cytoskeleton and drugs with an effect on cancer cell proliferation. For each target, we describe its bioactive properties and synthetic approaches. The wide variety of chemical structures compiled in this review and their significant medical properties may attract the attention of many different researchers.

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Formation of 3,4‐Diarylpyrrole‐ and Pyrrolocoumarin Core of Natural Marine Products via Barton–Zard Reaction and Selective O‐Demethylation

et al. 2020

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A metal-free approach to 3,4-diarylpyrrole-2-carboxylate and pyrrolocoumarin cores of lamellarins and related natural products based on Barton-Zard reaction of nitrostilbenes with ethyl isocyanoacetate was developed. In the case of diarylpyrrole-2-carboxylates with a 3-(o-methoxyphenyl)[a] N. Scheme 1. Formation of the lactone fragment. Results and Discussion An Approach to 3,4-Diarylpyrrole CoreSurprisingly, a Barton-Zard reaction [21] (that is, base-catalyzed reaction of nitroalkenes with alkyl isocyanoacetate) has not yet been reported for synthesis of the pyrrole core of lamellarins and related compounds, [22] though such reaction with 1,2-diaryl-1-nitroethylenes should be a straightforward way of accessing 3,4-diarylpyrrole-2-carboxylates as key structural fragments of the lamellarins, ningalins, and lukianols. Scheme 2. Synthesis of Lamellarin Q Et ester. i: CNCH 2 COOEt, EtOH, K 2 CO 3 , 87 %; ii: BBr 3 (3 equiv.), CH 2 Cl 2 , 0°C, 85 %; iii: BBr 3 (2 equiv.), CH 2 Cl 2 , 0°C, 63 %; iv: 4-HOC 6 H 4 CHO, MeOH, MeNH 2 ·HCl, NaHCO 3 ; v: CNCH 2 COOEt, EtOH, K 2 CO 3 . EurJOCEuropean Journal of Organic Chemistry demethylated under the action of BBr 3 (3 equiv.) to afford lamellarin Q Et ester (Scheme 2):Noteworthy, the reaction in the presence of 2 equiv. of BBr 3[24] demonstrated a pronounced selectivity: it produced a mixture of partially demethylated products 2b and 2c in ca. 1:4 ratio. The structure of a minor product (2b) was confirmed by its alternative synthesis from 2-(4-hydroxyphenyl)-1-(4-methoxyphenyl)-1-nitroethene 1b (Scheme 2) (the latter was, in turn, prepared by condensation of 4-methoxyphenylnitromethane and 4-hydroxybenzaldehyde).Demethylation of methyl 3,4-bis(4-methoxyphenyl)pyrrole-2carboxylate 3a with excess BBr 3 (3 equiv.) furnished lamellarin Q (Scheme 3, Figure 2): Scheme 3. Synthesis of Lamellarin Q. i: BBr 3 (3 equiv.), CH 2 Cl 2 , 0°C, 84 %; ii: MeONa, reflux, 84 %; iii: CNCH 2 COOEt, MeOH, K 2 CO 3 , 89 %.Figure 2. Molecular structure of Lamellarin Q·MeCN (50 % ellipsoids).

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Synthesis of Lamellarin G Trimethyl Ether by von Miller–Plöchl‐Type Cyclocondensation

Cited by 22 publications

References 58 publications

Marine Pyrrole Alkaloids

Marine Pyrrole Alkaloids

Marine Heterocyclic Compounds That Modulate Intracellular Calcium Signals: Chemistry and Synthesis Approaches

Formation of 3,4‐Diarylpyrrole‐ and Pyrrolocoumarin Core of Natural Marine Products via Barton–Zard Reaction and Selective O‐Demethylation

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