Total Synthesis of Pyrophen and Campyrones A–C

Reber, Keith P.; Burdge, Hannah E.

doi:10.1021/acs.jnatprod.7b00720

Cited by 15 publications

(16 citation statements)

References 40 publications

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“…We reasoned that late-stage oxidation of the propyl side chain (i.e., conversion of 3 to 2 ) would permit us easier passage through the earlier stage of the synthesis. Given these considerations, we were drawn to direct enolate C -acylation tactics, and Katritzky’s N -acyl benzotriazole tactic stood out among the array of options. − Among the virtues of N -acylbenzotriazoles is their ease of preparation, bench stability, and even commercial availability…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Deoxyradicinin, an Inhibitor of Xylella fastidiosa and Liberibacter crescens, a Culturable Surrogate for Candidatus Liberibacter asiaticus

et al. 2020

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Pierce's disease of grapevine and citrus huanglongbing are caused by the bacterial pathogens Xylella fastidiosa and Candidatus Liberibacter asiaticus (CLas), respectively. Both pathogens reside within the plant vascular system, occluding water and nutrient transport, leading to a decrease in productivity and fruit marketability and ultimately death of their hosts. Field observations of apparently healthy plants in disease-affected vineyards and groves led to the hypothesis that natural products from endophytes may inhibit these bacterial pathogens. Previously, we showed that the natural product radicinin from Cochliobolus sp. inhibits X. fastidiosa. Herein we describe a chemical synthesis of deoxyradicinin and establish it as an inhibitor of both X. fastidiosa and Liberibacter crescens, a culturable surrogate for CLas. The key to this three-step route is a zinc-mediated enolate C-acylation, which allows for direct introduction of the propenyl side chain without extraneous redox manipulations. P ierce's disease of grapevine and citrus huanglongbing (also known as citrus greening) are devastating plant diseases threatening important US agricultural industries. Both are caused by Gram-negative bacterial pathogens, spread by way of insect vectors. Pierce's disease, known in California since the 1800s, is caused by the bacterium Xylella fastidiosa, which inhabits the xylem of the plant. 1−3 As bacteria levels increase, the xylem becomes blocked and the flow of water and nutrients from the roots to the leaves is impeded, resulting in discolored and dried leaves, shriveled fruit, and stunted vine growth, ultimately leading to vine death. 4−6 X. fastidiosa is transmitted by xylem-feeding insects commonly known as leafhoppers. Native leafhoppers are limited in their flight range and transmission efficiency, and until recently, Pierce's disease outbreaks remained mostly isolated to small areas at a time. However, in 1989, an especially effective insect vector, the glassy-winged sharpshooter, was introduced to Southern California. The glassy-winged sharpshooter has infested most of Southern California, including the Malibu, Temecula Valley, and San Diego wine regions, and has made its way north into the Central Valley, posing an imminent threat to the California wine, raisin, and table grape industries.Huanglongbing is caused by the unculturable bacterium Candidatus Liberibacter asiaticus (CLas). 7−9 Unlike X. fastidiosa, CLas colonizes the phloem (food transport tissue) of citrus trees. Huanglongbing-infected trees experience root loss, dieback, starch buildup, and mottled yellow leaves. 10,11 Affected fruit are often green, stunted, and bitter and may drop prematurely. 12,13 Huanglongbing can drastically impact the yield productivity of a tree and can ultimately prove fatal. CLas

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Section: Resultsmentioning

confidence: 99%

Synthesis of Deoxyradicinin, an Inhibitor of Xylella fastidiosa and Liberibacter crescens, a Culturable Surrogate for Candidatus Liberibacter asiaticus

et al. 2020

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“…According to the preliminary bio-activity assays, and compound 4 was found to inhibit the proliferation of cancer cells, especially for TNBC. In order to obtain a high content of target compounds in a mild and economic manner for further evaluation in anticancer assays, we poured our attention to the C–N coupling strategy about inexpensive catalyst of N , N -4-dimethyl-4-aminopyridine (DMAP) [20,21,22].…”

Section: Resultsmentioning

confidence: 99%

Cytisine-Pterocarpan Derived Compounds: Biomimetic Synthesis and Apoptosis-Inducing Activity in Human Breast Cancer Cells

et al. 2018

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Cytisine-pterocarpan derived compounds were biomimetically synthesized with (-)-cytisine and (-)-maackiain via a N,N-4-dimethyl-4-aminopyridine (DMAP)-mediated synthetic strategy in a mild manner. In the present study, tonkinensine B (4) was elaborated in good and high yields with the optimized reaction conditions. The in vitro cytotoxicity of compound 4 was evaluated against breast cancer cell lines and showed that 4 had a better cytotoxicity against MDA-MB-231 cells (IC50 = 19.2 μM). Depending on the research on cytotoxicities of 4 against RAW 264.7 and BV2 cells, it was suggested that 4 produced low cytotoxic effects on the central nervous system. Further study indicated that 4 demonstrated cytotoxic activity against MDA-MB-231 cells and the cytotoxic activity was induced by apoptosis. The results implied that the apoptosis might be induced by mitochondrion-mediated apoptosis via regulating the ratio of Bax/Bcl-2 and promoting the release of cytochrome c from the mitochondrion to the cytoplasm in MDA-MB-231 cells.

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“…Even though their presence is common in the genus, the biological function associated with this compound remains largely undescribed. Similarly to nigerone, which also belongs to the group of naphto-γ-pyrones, as well as pyrophen, which belongs to another pyrone group [53], those secondary metabolites have been described in phytopathogenic fungi, but their role in disease progression is yet unknown [52].…”

Section: Discussionmentioning

confidence: 99%

Calm Before the Storm: A Glimpse into the Secondary Metabolism of Aspergillus welwitschiae, the Etiologic Agent of the Sisal Bole Rot

Quintanilha-Peixoto

Torres

Reis

et al. 2019

Toxins

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Aspergillus welwitschiae is a species of the Nigri section of the genus Aspergillus. In nature, it is usually a saprotroph, decomposing plant material. However, it causes the bole rot disease of Agave sisalana (sisal), a plant species used for the extraction of hard natural fibers, causing great economic loss to this culture. In this study, we isolated and sequenced one genome of A. welwitschiae (isolate CCMB 674 (Collection of Cultures of Microorganisms of Bahia)) from the stem tissues of sisal and performed in silico and wet lab experimental strategies to describe its ability to produce mycotoxins. CCMB 674 possesses 64 secondary metabolite gene clusters (SMGCs) and, under normal conditions, it produces secondary metabolism compounds that could disturb the cellular cycle of sisal or induce abnormalities in plant growth, such as malformin C. This isolate also produces a pigment that might explain the characteristic red color of the affected tissues. Additionally, this isolate is defective for the production of fumonisin B1, and, despite bearing the full cluster for the synthesis of this compound, it did not produce ochratoxin A. Altogether, these results provide new information on possible strategies used by the fungi during the sisal bole rot, helping to better understand this disease and how to control it.

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Total Synthesis of Pyrophen and Campyrones A–C

Cited by 15 publications

References 40 publications

Synthesis of Deoxyradicinin, an Inhibitor of Xylella fastidiosa and Liberibacter crescens, a Culturable Surrogate for Candidatus Liberibacter asiaticus

Synthesis of Deoxyradicinin, an Inhibitor of Xylella fastidiosa and Liberibacter crescens, a Culturable Surrogate for Candidatus Liberibacter asiaticus

Cytisine-Pterocarpan Derived Compounds: Biomimetic Synthesis and Apoptosis-Inducing Activity in Human Breast Cancer Cells

Calm Before the Storm: A Glimpse into the Secondary Metabolism of Aspergillus welwitschiae, the Etiologic Agent of the Sisal Bole Rot

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