Picraviane A and B: Nortriterpenes with limonoid-like skeletons containing a heptanolide E-ring system from Picramnia glazioviana

Gimenes, Leila; Batista, João M.; Santos, Fernando Martins dos; Souza, Matheus da Silva; Luna-Dulcey, Liany; Ellena, Javier; Cominetti, Márcia Regina; Silva, Maria Fátima das Graças Fernandes da; Vieira, Paulo C.; Fernandes, João B.

doi:10.1016/j.phytochem.2019.03.024

Cited by 11 publications

(26 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…VCD spectroscopy has already been demonstrated as a powerful tool to distinguish epimeric compounds when the use of NMR spectroscopy leads to ambiguous conclusions. 13,14 As expected, the IR and VCD spectra calculated for the C-13 epimers of 2 were very similar (Figure 2). A band at 1255 cm −1 , however, which arises from sp 3 -CH and CH 2 deformation modes involving most of the molecular framework, was oppositely signed in the calculated epimers.…”

Section: ■ Results and Discussionsupporting

confidence: 76%

“…Since no X-ray crystallography data were available to determine the relative configuration of compound 2 , vibrational circular dichroism (VCD) spectral calculations were performed for both epimers possible at C-13, that is, 5 R ,8 S ,9 S ,10 R ,13 R and 5 R ,8 S ,9 S ,10 R ,13 S . VCD spectroscopy has already been demonstrated as a powerful tool to distinguish epimeric compounds when the use of NMR spectroscopy leads to ambiguous conclusions. , As expected, the IR and VCD spectra calculated for the C-13 epimers of 2 were very similar (Figure ). A band at 1255 cm –1 , however, which arises from sp 3 -CH and CH 2 deformation modes involving most of the molecular framework, was oppositely signed in the calculated epimers.…”

Section: Results and Discussionsupporting

confidence: 63%

See 1 more Smart Citation

Phytotoxic Neocassane Diterpenes fromEragrostis plana

Hendges

Santos

Teixeira³

et al. 2020

J. Nat. Prod.

View full text Add to dashboard Cite

Five new neocassane-like diterpenes (1–5) were isolated from the roots of Eragrostis plana. Their structures were elucidated by spectroscopic data, and the absolute configurations of the representative compounds neocassa-12(17),15-dien-3-one (2) and neocassa-12(13),15-diene-3,14-dione (5) were assigned by vibrational circular dichroism. The phytotoxic activity of compounds 3, 4, and 5 was evaluated against the germination and growth of Ipomoea grandifolia and Euphorbia heterophylla. Compound 4 exhibited the most potent activity for growth variables, resulting in the smallest radicle length of I. grandifolia and in the smallest aerial part length of E. heterophylla. Compound 5 reduced the germination speed index more effectively than the herbicide glyphosate (Roundup).

show abstract

Section: ■ Results and Discussionsupporting

confidence: 76%

Section: Results and Discussionsupporting

confidence: 63%

Phytotoxic Neocassane Diterpenes fromEragrostis plana

Hendges

Santos

Teixeira³

et al. 2020

J. Nat. Prod.

View full text Add to dashboard Cite

show abstract

“…The AC of both compounds was ascertained by VCD spectroscopy. 69 ECD, Raman optical activity, and VCD methodologies were used to characterize (3R,3'R)-astaxanthin (125) and (3S,3′S)astaxanthin (126) ( Figure 33). Commercially available racemic astaxanthin was separated into the enantiomers by column chromatography after bis-[(−)camphanic] ester derivatization.…”

Section: Monoterpenoids the Formulas Of The 28 Monoterpenoids Includmentioning

confidence: 99%

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Río

Joseph‐Nathan

2021

Natural Product Communications

View full text Add to dashboard Cite

Although demonstrated in 1975, vibrational circular dichroism (VCD) finally started to popularize during this century as a reliable tool to determine the absolute configuration (AC) of organic molecules. This research field continues to be a very dynamic one, in particular for the study of natural products which are a unlimited source of chiral molecules. It therefore turns of interest to summarize the accomplishments published in recent years and to comment on some eventual difficulties that emerged in rare cases to complete the AC determination task. Therefore the aim of this review is to update VCD results for the AC assignment of natural products published from 2015 to 2019, a period in which VCD was reported in some 126 publications involving almost 300 molecules. They are organized according the type of studied metabolite allowing an easily search. The molecules correspond to 28 monoterpenes concerning 17 papers, to 42 sesquiterpenes in 14 papers, to 51 diterpenes in 19 publications, to 5 other terpenoids in three papers, to 48 aromatic molecules in 15 reports, to 20 polyketides in 10 publications, to 27 miscellaneous formulas also in 10 papers, and to 76 nitrogen containing compounds, which include alkaloids and their synthetic analogs, in 38 articles. The landscape of reviewed molecules is quite wide as it goes from simple monoterpenes, like borneol or camphor, to very relevant biological molecules like the alkaloid cocaine or tadalafil samples to distinguish genuine and counterfeit Cialis®. In addition, 5 natural products and a simple derivative published outside the reviewed period, were used to illustrate some aspects of density functional theory calculations.

show abstract

“…In this section, we will present a list of natural products and related compounds studied by Brazilian researchers (Table S1), which had their absolute configuration assigned using VCD spectroscopy and DFT calculations, associated or not with other techniques (Batista Jr et al 2011b;2013;2015b;Batista et al 2019;Caldas et al 2020;Caleffi et al 2019;Canzi et al 2018;Covington et al 2016;Demarque and Merten 2017;Felippe et al 2012;Gimenes et al 2019;Joseph-Nathan et al 2010;Lianza et al 2020;Londero et al 2021;Medina et al 2019;Morais et al 2020;Ortega et al 2017;Ortega et al 2018;Ortega et al 2019;Queiroz et al 2019;Rodriguez et al 2020;Santos Jr et al 2014;Scatena et al 2017;Socolsky et al 2012;Souza et al 2019;Teodoro et al, 2018a;2018b). Some selected examples will be discussed in detail below.…”

Section: Applications Of Vcd In Brazilmentioning

confidence: 99%

Vibrational Circular Dichroism for the Assignment of Absolute Configuration of Natural Products in Brazil

Batista

Valverde

Batista

2021

Rev. Bras. Farmacogn.

View full text Add to dashboard Cite

The determination of the absolute configuration of chiral bioactive natural products is a crucial step in their structural characterization. Several well-established techniques, such as X-ray crystallography, stereo-controlled organic synthesis, NMR, and chiroptical spectroscopy, are commonly used to this end. However, even today, the configurational analysis of natural products remains a challenge, with a significant number of reassignments being reported every year. Among chiroptical methods, vibrational circular dichroism (VCD) has emerged as an excellent tool for the assignment of the absolute configuration of structurally diverse chiral natural products directly in solution. This review covers the use of VCD spectroscopy to elucidate the absolute stereochemistry of natural products in Brazil over the last 20 years. Although the number of VCD investigations on secondary metabolites has increased, VCD can still be considered under-explored in Brazil. Therefore, herein, we aim to demonstrate the unparalleled stereochemical discriminatory power of VCD to assign both conformation and absolute configuration of natural products in conditions not commonly accessible to other techniques.

show abstract

Picraviane A and B: Nortriterpenes with limonoid-like skeletons containing a heptanolide E-ring system from Picramnia glazioviana

Cited by 11 publications

References 31 publications

Phytotoxic Neocassane Diterpenes fromEragrostis plana

Phytotoxic Neocassane Diterpenes fromEragrostis plana

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Vibrational Circular Dichroism for the Assignment of Absolute Configuration of Natural Products in Brazil

Contact Info

Product

Resources

About