A 13 C NMR study of the structure of four cinnamic acids and their methyl esters

Silva, A.M.S.; Alkorta, Ibón; Elguero, José; Silva, V.L.M.

doi:10.1016/s0022-2860(01)00486-0

Cited by 20 publications

(11 citation statements)

References 16 publications

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“…[21][22][23][24][25] The integration of the 1 H NMR signals allowed us to calculate the approximate relative percentage of both compounds: 36.16% of 8 and 63.84% of 9.…”

Section: Resultsmentioning

confidence: 99%

“…[21][22][23][24][25] 15 = m/z 868.5058), besides additional peaks compatible with loss of sugar moieties, were used to confirm the molecular formula of these isomeric compounds (13 and 14). The hydrogen and carbon atoms signals observed in the 1 H and 13 C NMR spectra of 13-17 (Tables 1 and 3) were also assigned with aid of the homonuclear 2D 1 H-1 H-COSY and heteronuclear 2D HMQC ( 1 H-13 C-COSY-1 J CH ) and HMBC ( 1 H-13 C-COSY-n J CH , n = 2 and 3), allowing to identify the 1 H chemical shifts of the methyl group signals of the aglycone and of the trisaccharide moieties ( Figure 1.…”

Section: Resultsmentioning

confidence: 99%

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Other chemical constituents isolated from Solanum crinitum Lam. (Solanaceae)

Cornelius

Carvalho

Alves

et al. 2010

J. Braz. Chem. Soc.

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(7), ácido 4-hidroxibenzoico (12), e quatro derivados do ácido cinâmico: cis-e trans-cumárico (10 e 11), cis-e trans-cumarato de etila (8 e 9), isolados de tricomas do fruto. Do extrato metanólico de frutos verdes foram isolados três alcalóides esteroidais glicosilados: solamargina (13), 20-epi-solamargina (14) e solasonina (16). Os derivados 3,5,7,4'-tetra-O-metil-kaempferol (4), 3,7,4'-tri-O-metil-kaempferol (5), 3,7,4'-tri-O-metil-5-Oacetil-kaempferol (6), peracetil-epi-solamargina (15) e peracetil-solasonina (17) foram sintetizados e estão sendo registrados pela primeira vez na literatura. As estruturas foram definidas através de análise de dados espectrométricos.The phytochemical investigation of Solanum crinitum Lam led to the isolation from the fruit trichomes of four flavonoids, tiliroside (1), astragalin (2), kaempferol (3), biochanin A-7- O-b-D-apiofuranosyl-(1→5)-b-D-apiofuranosyl-(1→6)-b-D-glucopyranoside (7), along with 4-hydroxybenzoic acid (12), and four cinnamic acid derivatives, cis-and trans-coumaric acids (10 and 11) and cis-and trans-ethyl coumarate (8 and 9). Three tri-glycosyl-steroidal alkaloids, solamargine (13), 20-epi-solamargine (14) and solasonine (16) were isolated from the methanolic extract of the green fruits. The derivatives 3,5,7,4'-tretra-O-methyl-kaempferol (4), 3,7,4'-tri-O-methyl-kaempferol (5), 3,7,4'-tri-O-methyl-5-O-acetyl-kaempferol (6), the peracetyl-episolamargine (15) and peracetyl-solasonine (17) were prepared. The structures were established through the analysis of their spectral data. The complete 1 H and 13 C NMR data assignments of the new peracetyl derivatives of the alkaloids were made.Keywords: Solanum crinitum, Solanaceae, steroidal glycoalkaloids, flavonoids, cinnamic acids Introduction Solanum (L) is the most representative genus of Solanaceae, containing about 1,500 species, and 5,000 epithets. It is widespread in tropical and subtropical regions of all the world, but its highest diversity occurs in South America. 1 Solanum species are a rich source of steroidal alkaloids, flavonoids and their glycosides which are known to possess a variety of biological activities. The glycoalkaloids are natural toxins with ecological and human health importance, such as the allelopathic effect against herbivores, against pathogenic microorganism 2,3 and molluscicidal activity, 4 and are also of interest as starting material for anabolic, anti-fertility, anti-inflammatory, anti-allergic drugs. 5 As the alkaloids, the flavonoids are a frequent group of compounds in Solanum species, and can be used as systematic markers for the family taxons. [6][7][8] Solanum crinitum Lam (Solanaceae), popularly known as "jurubeba" and "fruto-de-lobo", is a shrub or small tree in South America, including southern Brazil and Colombia. 9,10 In the course of our pharmacological and phytochemical investigations of Solanum species, 3,4,8,[11][12][13] we have reported the cytotoxic and antitumoral activities of flavonoids isolated from trichomes of young branches Other Chemical Constituents Is...

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“…[21][22][23][24][25] The integration of the 1 H NMR signals allowed us to calculate the approximate relative percentage of both compounds: 36.16% of 8 and 63.84% of 9.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Other chemical constituents isolated from Solanum crinitum Lam. (Solanaceae)

Cornelius

Carvalho

Alves

et al. 2010

J. Braz. Chem. Soc.

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“…It should be noted here that, as is characteristic of CAs whose crystal structures have been determined, the two C-O bond distances in the carboxy group are not significantly different from one another and the carboxy group is disordered by interchange of carbonyl and hydroxy groups. Very recently, Silva et al [23] studied the molecular structure ofp-MeCA in solution by measuring ~3C NMR spectra. They showed that the differences between the absolute shieldings ofp-MeCA-1 and p-MeCA-2 are very small.…”

Section: Conformers and Sublevel Kineticsmentioning

confidence: 99%

Optical and time-resolved electron paramagnetic resonance studies of the excited states of para-methylcinnamic acid and para-methylcinnamate anion

et al. 2003

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Time-resolved electron pammagnetic resonance (EPR), fluorescence, and phosphorescence spectra have been observed for the excited states of trans-p-methylcinnamic acid (p-MeCA) and transp-methylcinnamate anion (p-MeCA-) in rigid organic glasses at 77 K. With a stretched-polymer-film techrtique, we assigned the resonance fields in the time-resolved EPR spectra of the lowest excited t¡ (T~) states of p-MeCA and p-MeCA-. From the analysis of these spectra we concluded that the deviation from planar structure in the T~ state is small in p-MeCA and p-MeCA-and the direction of C=O is s-cis to the ethylenic C=C bond in p-MeCA. The deprotonation appears to have little effect on the zero-field splitting (ZFS) parameters. The ZFS parameters were calculated theoretically using semiempi¡ molecular orbitals. The sublevel preferentially populated by intersystem crossing (ISC) is Ty in both p-MeCA and p-MeCA-. However, following the deprotonation of p-MeCA, (Py -P~)/(Px -P~) changes from 5.7 in p-MeCA to 2.1 in p-MeCA-(Pi are relative populating rates; the x and y axes are close to the Iong and short in-plane molecular axes, respectively, and z-axis is perpendicular to the molecular plane). The fluoreseenee lifetimes indicate that the deprotonation has little effeet on the sum of the three [SC rate constaats for the three T~ sublevels. A decrease in aeidity of p-MeCA upon exeitation has been observed.

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“…β-carotene (1), steroids sitosterol (2), stigmasterol (3) and campesterol (4), α-tocopherol (5), vanillic (6) and ferulic acids (7), tricin (8), sitosterol glucoside (9) and p-hydroxycinnamic (10) and p-hydroxybenzoic acids (11) (Figure 1) were isolated from the ethyl acetate extract and identified by interpretation of 1 H, 13 C, DEPT and COSY NMR spectral data and comparison with literature data (Miranda et al 2012, Goulart et al 1993, Yu et al 2006, Sajjadi et al 2012, Chung et al 2005, Lee et al 2007, Silva et al 2001, Scott 1972 C NMR spectrum showed resonances at δ C 158. 6, 94.8, 164.9, 99.6, 162.2 and 104.9, attributed to carbons C-9, C-8, C-7, C-6, C-5 and C-10 of ring A, respectively.…”

Section: Resultsmentioning

confidence: 89%

Phenolic compounds and anticancer activity of commercial sugarcane cultivated in Brazil

Alves

Souza

Chiavelli

et al. 2016

An. Acad. Bras. Ciênc.

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The cultivation of sugarcane hybrids (X Saccharum officinarum L.) is an important revenue source for the Brazilian economy. Herein it is reported the evaluation of the cytotoxic activity of mid-polarity sugarcane extracts against human cancer cell lines, as well as the isolation of steroids sitosterol, stigmasterol and campesterol, phenolic acids p-hydroxybenzoic, p-hydroxycinnamic, vanillic and ferulic acid, terpenoids α-tocopherol and β-carotene and a novel substance in sugarcane, the flavonoid aglycone tricin (5,7,4-trihydroxy-3,5-dimethoxyflavone). The presence of large amounts of phenolic acids and the flavonoid tricin may explain the cytostatic activity observed for the mid-polarity crude extract and filtrates.

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A 13 C NMR study of the structure of four cinnamic acids and their methyl esters

Cited by 20 publications

References 16 publications

Other chemical constituents isolated from Solanum crinitum Lam. (Solanaceae)

Other chemical constituents isolated from Solanum crinitum Lam. (Solanaceae)

Optical and time-resolved electron paramagnetic resonance studies of the excited states of para-methylcinnamic acid and para-methylcinnamate anion

Phenolic compounds and anticancer activity of commercial sugarcane cultivated in Brazil

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