Structure of pretoxin and lambicin

Corbella, A.; Jommi, G.; Rindone, B.; Scolastico, Carlo

doi:10.1016/s0040-4020(01)83024-6

Cited by 9 publications

(18 citation statements)

References 3 publications

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“…23 However, database searching from predicted molecular formulas, together with taxonomic considerations, suggested the presence of pretoxin or its isomers. 24 Despite a moderate ranking (22 nd candidate considering the CSI:FingerID bio database), this information was corroborated by using Sirius. 25,26 The new compounds of interest were detected as present mainly in the fruit EtOAc extract of Austrobuxus carunculatus.…”

Section: Resultsmentioning

confidence: 95%

“…Its MS-guided chemical investigation led to the isolation of 14 picrotoxanes for which the structures were elucidated by HRESIMS and NMR spectroscopic data analysis (Tables 1-4, Table S1 Analysis of its data allowed compound 3 to be identified as an epimer of the known pretoxin. 24 In contrast to monolactone picrotoxanes such as compounds 1 and 2, the so-called "norditerpene" picrotoxanes possess an extended carbon skeleton. The main difference between compounds 1 and 3 was the presence of a substituted spiro g-butyrolactone at C-13 in 3 instead of the spiro-epoxy moiety in 1.…”

Section: Resultsmentioning

confidence: 99%

“…In the literature, the absence of crystallographic data and complete NMR data for pretoxin did not allow their comparison with those of compound 3. Only the melting points of the two compounds could be compared and proved to be different, confirming their structural difference (Mp = 128-130°C24 and 208-210°C for pretoxin and 16-epi-pretoxin, respectively).The HRESIMS data of compound 4 showed a [M+H] + ion peak at m/z 563.3176 (calcd for C31H47O9 + , 563.3215), corresponding to the molecular formula, C31H46O9. The NMR spectroscopic data showed the presence of similar structural features to those of 16-epipretoxin.…”

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confidence: 98%

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Isolation of Picrotoxanes from Austrobuxus carunculatus Using Taxonomy-Based Molecular Networking

et al. 2020

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A unique collection of 292 extracts from 107 New Caledonian Euphorbiaceae species sensu lato was profiled by LC-MS2 and the metabolite content organized by molecular networking. Based on the assumption that taxon-specific molecules are more likely to be structurally novel, taxonomic data were mapped on spectral networks to detect genus-specific clusters. Using this approach, a group of compounds unique to the genus Austrobuxus was highlighted. The subsequent MS-guided purification of the fruit EtOAc extract of Austrobuxus carunculatus led to the isolation of 13 new monolactone and “norditerpene” picrotoxanes (2–14), along with the known tutin (1). The structures of the new compounds were elucidated by HRESIMS and NMR spectroscopic data analysis, and the absolute configurations of compounds 1, 3, 7, 11, 12, and 14 were determined by single-crystal X-ray diffraction analysis. The relative and absolute configurations of compounds 4 and 5 were ascertained by chemical transformation of compound 3. The absolute configurations of other members of the series have been proposed on the basis of biogenetic considerations and specific rotation values of similar sign and magnitude. Compounds 1–14 were evaluated for their antiproliferative activities against HCT116 colon, U87-MG glioblastoma, and A549 lung human cancer cell lines. Compounds bearing an acyl chain at C-2 (i.e., 2, 4, and 13) showed IC50 values in the micromolar range for the three cell lines used.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

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confidence: 98%

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Isolation of Picrotoxanes from Austrobuxus carunculatus Using Taxonomy-Based Molecular Networking

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“…Reduction of pyrrole-2carboxylic acid (Aldrich P-7, 360-9) was performed with 60% yield using H3 PO2 /HI in acetic acid (Corbella et al, 1969). The 360MHz 'H n.m.r.…”

Section: Acid)mentioning

confidence: 99%

“…Pyrrole-2-carboxylic acid was first reduced (Corbella et al, 1969) t o 3-pyrroline-2carboxylic acid and this was subsequently deuterated (Felix et al, 1977). The racemic 3,4-dideuteroproline was revealed by 'H n.m.r.…”

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confidence: 99%

PREPARATION OF RACEMIC 2r‐CARBOXY‐TRANS, TRANS‐3, 4‐DIDEUTERO‐PYRROLIDINE (DL‐TRANS, TRANS‐3, 4‐DIDEUTERO‐PROLINE) AND UNAMBIGUOUS ASSIGNMENT OF PROTONS IN THE 1H N.M.R. SPECTRUM OF PROLINE

Anteunis

Borremans

Becu

et al. 1979

International Journal of Peptide and Protein Research

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Racemic trans, trans-3.4-dideutero proline has been prepared by catalytic deuteration of 3-pyrroline-2-carboxylic acid, The stereospecificity o f the reduction (i.e. trans to the carboxylic group) was ascertained after transformation of the dideutero compound into the diketopiperazide c/Pro, Aibl, for which unambiguous proton assignments in the ' H n.m.r. spectrum had been obtained previously. The identification of the configuration of the dideuteroproline allows for the affirmation of the correctness o f proton assignments aspreviously proposed in literature.

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Sesquiterpenoids

Connolly¹,

Hill²

1991

Dictionary of Terpenoids

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Structure of pretoxin and lambicin

Cited by 9 publications

References 3 publications

Isolation of Picrotoxanes from Austrobuxus carunculatus Using Taxonomy-Based Molecular Networking

Isolation of Picrotoxanes from Austrobuxus carunculatus Using Taxonomy-Based Molecular Networking

PREPARATION OF RACEMIC 2r‐CARBOXY‐TRANS, TRANS‐3, 4‐DIDEUTERO‐PYRROLIDINE (DL‐TRANS, TRANS‐3, 4‐DIDEUTERO‐PROLINE) AND UNAMBIGUOUS ASSIGNMENT OF PROTONS IN THE 1H N.M.R. SPECTRUM OF PROLINE

Sesquiterpenoids

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