Alkylthiolation for the determination of double-bond positions in linear alkenes

Francis, George W.; Veland, Knut

doi:10.1016/s0021-9673(00)80381-7

Cited by 217 publications

(128 citation statements)

References 15 publications

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“…Because of the double allylic hydrogen signal integration, it was concluded that the mixture is composed of 27% of diene and 73% of monoene for the cardols and 60% of monoene and 40% of diene for cardanols. This analysis was confirmed by 13 C NMR spectroscopy (Table 1) which showed a good correlation between observed and calculated 13 C chemical shifts, using the principle of substituent additivity [21].…”

Section: Resultssupporting

confidence: 58%

“…The position of the double bonds of unsaturated hydrocarbons was determined by iodinecatalyzed methylthiolation using dimethyl disulphide -DMDS [12][13][14][22][23]. Approximately 50 mg of the phenolic fraction was kept dehydrated using anhydrous calcium chloride for 24 hours and then incubated with 0.3 mL of DMDS containing 10 mg/mL in ethyl ether of I 2 at 25 o C, for 4 hours.…”

Section: Alkylthiolation Reactionmentioning

confidence: 99%

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Anacardic acid derivatives from Brazilian propolis and their antibacterial activity

et al. 2008

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Propolis is a sticky, gummy, resinous substance collected by honeybees (Apis mellifera L.) from various plant sources, which has excellent medicinal properties. This paper describes the isolation and identification of triterpenoids and anacardic acid derivatives from Brazilian propolis and their antibacterial activity. Their structures were elucidated by ¹H and 13C NMR, including uni- and bidimensional techniques; in addition, comparisons were made with data from academic literature. These compounds were identified as: cardanols (1a + 1b), cardols (2a + 2b), monoene anacardic acid (3), a-amirine (4), b-amirine (5), cycloartenol (6), 24-methylene-cycloartenol (7) and lupeol (8). The determination of the position of the double bond after a reaction with Dimethyl disulfide (DMDS) is described for the phenol derivatives. The ethanolic extract was tested in vitro for antimicrobial activity by using the disc diffusion method and it showed significant results against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Shigella spp.

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Section: Resultssupporting

confidence: 58%

Section: Alkylthiolation Reactionmentioning

confidence: 99%

Anacardic acid derivatives from Brazilian propolis and their antibacterial activity

et al. 2008

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“…The sterols were identified by comparison with literature data. [30][31][32] Methyl nonadeca-15, 17-dienoate (1) M + 308, C 20 H 36 O 2 (40 mg, methanol), mp [90][91][92] 77.9; H, 11.68; Calc. : C, 77.7; H, 11.65%), isolated from hexane: benzene (4:1, v/v) fraction.…”

Section: Extraction and Isolation Of The Constituentsmentioning

confidence: 99%

Novel lipid constituents identified in seeds of Nigella sativa (Linn)

Mehta¹,

Verma²,

Gupta³

2008

J. Braz. Chem. Soc.

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Lipídeos inéditos foram isolados de matéria insaponificável extraída de sementes de Nigella sativa Linn, usando-se n-hexano. O dienoato e os dois monoésteres inéditos foram identificados por técnicas espectrométricas, incluindo IV, RMN de 1 H e 13 C, espectrometria de massas, e análise química. O dienoato (1) foi identificado como metilnonadeca-15, 17-dienoato e os dois monoésteres foram identificados como pentil hexadec-12-enoato (2) e pentil pentadec-11-enoato (3). Ácido linoleico, ácido oléico, b-sitosterol e stigmasterol foram identificados como parte das estruturas dos lipídeos. Todos os compostos mostraram atividade moderada contra Staphylococcus aureus e baixa atividade contra shigella spp e Klebsiella pneumoniae.Novel lipids were isolated from the unsaponifiable matter extracted from seeds of Nigella sativa Linn by using n-hexane. The new dienoate and two monoesters were the new lipids identified by spectral (IR, 1 H-and 13 C-NMR spectra, mass spectrum, elemental analysis) and chemical analysis. The dienoate (1) was identified as methylnonadeca-15,17-dienoate and two monoesters were identified as pentyl hexadec-12-enoate (2) and pentyl pentadec-11-enoate (3). Linoleic acid, oleic acid, b-sitosterol and stigmasterol were identified as part of the lipid structures. All compounds exhibited moderate activity against Staphylococcus aureus and poor activity against shigella spp, and Klebsiella pneumoniae.Keywords: Nigella sativa, seeds, Ranunculaceae, aliphatic esters IntroductionNigella sativa Linn., a plant belonging to the family Ranunculaceae, grows as a small herb and is cultivated throughout India and other tropical regions of the world. 1,2 It is commonly known as black cumin seed and kalaungi in Hindi in India. The seed contains alkaloids nigellidine, 3 nigellimine and nigellicine, 4,5 tannin, steroids a-spinasterol, 6 campesterol, cholesterol, stigmasta-7-en3b-ol, stigmasterol and b-sitosterol, flavonoids of trigillin quercetin-3-glucoside, saponin and nigellone. 7,.8 Recent pharmacological investigations of the seed extract revealed that a wide spectrum of biological activities including anti-inflammatory, antidiabetic, analgesic, antibacterial, antifungal, anti-helmintic, 9 bronchodilatory, 10 hypertensive and immunoprotecting activities. 11 The seeds are believed to have carminative, diuretic, lactogoge, stimulatory and diaphoretic properties and are used in the treatment of bronchial asthma and eczema. [12][13][14][15] The hexane and benzene extracts of its seeds were exhibited 67% and 40% post-coital anti-implantation activity at the dose level of 500 mg kg -1 per day, respectively. 16 The present study reports the isolation and structural elucidation of three new lipids (Figure 1) isolated from seeds of Nigella sativa Linn. Linoleic acid, oleic acid, b-sitosterol and stigmasterol were identified as part of the structures of the new lipids. Results and DiscussionThe novel natural compounds were identified mainly by their 1D ( 1 H and 13 C NMR), 2D ( 1 H-1 H COSY), DEPT and mass spectrometry analy...

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“…Methyl-branched hydrocarbons were identified by diagnostic ions resulting from the favored fragmentation at the branching points (Lockey, 1988;Nelson, 1993) and by comparing LRI values with literature data (Carlson et al, 1998). Double bond position was determined by iodine-catalyzed methylthiolation using dimethyl disulfide (Francis and Velant, 1981;Howard, 1993). Peak areas for each compound were calculated and related to total peak area for each run.…”

Section: Bioassay: Activity Of Hydrocarbon Fractionsmentioning

confidence: 99%

Courtship Pheromones in Parasitic Wasps: Comparison of Bioactive and Inactive Hydrocarbon Profiles by Multivariate Statistical Methods

2007

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Cuticular hydrocarbons play a significant role in the regulation of cuticular permeability and also in the chemical communication of insects. In the parasitoid Lariophagus distinguendus (Hymenoptera: Pteromalidae), male courtship behavior is mediated by a female-produced sex pheromone. Previous studies have shown that the chemicals involved are already present in the pupal stage of both males and females. However, pheromonal activity in males decreases shortly after emergence. This pheromonal deactivation occurs only in living males, suggesting an active process rather than simple evaporation of bioactive compounds. Here, we present evidence that the sex pheromone of L. distinguendus is composed of a series of cuticular hydrocarbons. Filter paper disks treated with nonpolar fractions of cuticular extracts of freshly emerged males and females, 72-hr-old females, and yellowish pupae caused arrestment and stimulated key elements of courtship behavior in males, whereas fractions of 72-hr-old males did not. Sixty-four hydrocarbons with chain length between C 25 and C 37 were identified in the fractions by gas chromatography-mass spectrometry (GC-MS). Methyl-branched alkanes with one to four methyl groups were major components, along with traces of n-alkanes and monoalkenes. Principal component analysis, based on the relative amounts of the compounds, revealed that cuticular hydrocarbon composition differed among all five groups. By using partial least squares-discriminant analysis, we determined a series of components that differentiate bioactive and bioinactive hydrocarbon profiles, and may be responsible for pheromonal activity of hydrocarbon fractions in L. distinguendus.

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Alkylthiolation for the determination of double-bond positions in linear alkenes

Cited by 217 publications

References 15 publications

Anacardic acid derivatives from Brazilian propolis and their antibacterial activity

Anacardic acid derivatives from Brazilian propolis and their antibacterial activity

Novel lipid constituents identified in seeds of Nigella sativa (Linn)

Courtship Pheromones in Parasitic Wasps: Comparison of Bioactive and Inactive Hydrocarbon Profiles by Multivariate Statistical Methods

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