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Highlights from the article: Assignment of 1H and 13C NMR data for three pairs of diastereomers of 4'-X benzo[1,3]cyclopropa[1,2-b]chromene-4,5-diones (X = H, OCH3, and Cl) In the course of a microwave-assisted tandem reaction starting from 3-bromo-2-styrylchromones B 1 b , an intermediate having the structure of a benzo[1,3]cyclopropa[1,2- I b i ]chromene-4,5-dione B 2 b was isolated, leading to cyclohepta[ I b i ]chromene-9,11-diones B 3 b (Scheme).[1] Intermediates B 2 b were obtained through a tandem 1,6-conjugate addition/Michael-initiated ring closure/imine hydrolysis reaction of 1-(prop-1-en-2-yl)pyrrolidine with 3-bromo-2-styrylchromones B 1 b .[1] Of compound B 2 b , two diastereomers were obtained in a near 1:1 ratio, although both are a mixture of two enantiomers due to the presence of a fourth stereogenic center at C10a (we have carried out our calculations on the 10a I S i ). Using some of the techniques available in NMR spectroscopy, several things were achieved: (a) the stereochemistry of carbon atoms at positions 2, 4a, and 4b was established and assigned to B 2d b SB B 1 b sb and B 2d b SB B 2 b sb diastereomers and (b) the chemical shifts of a large number of protons and carbon atoms were assigned (in black in the following tables). Part of the success is related to the fact that the chemical shifts of both diastereomers were determined simultaneously, so very small differences (0.004 ppm in SP 1 sp H NMR and 0.01 ppm in SP 13 sp C NMR) were sufficient to observe two signals.

Graphical abstract Ruthenium(II) trithiacyclononane complexes of three naturally occurring flavones are obtained in yields of 23–43%. One of these, [Ru(II)([9]aneS 3)(thflv)(DMSO)], (thflv = 7,3′,4′-trihydroxyflavone) exhibits coordination at the catechol group, a rare feature in Ru(II)-O,O′ complexes. The in vitro cytotoxic activity of the flavones and their corresponding Ru(II) complexes is presented. Highlights • 7,3′,4′-Trihydroxyflavone forms a neutral Ru(II) complex via catechol O,O′-coordination. • Chrysin and techtochrysin form cationic complexes with Ru(II) via bidentate chromenone binding. • Chrysin may be a natural alternative to cisplatin in osteosarcoma treatment. Abstract This study describes a simple, two-step method for obtaining ruthenium(II) trithiacyclononane ([9]aneS 3) flavonate complexes in yields ranging from 23% to 34%. With 7,3′,4′-trihydroxyflavone (thflv), a neutral complex, [Ru(II)([9]aneS 3)(DMSO)(thflv)] (1), is formed by coordination at the catechol group. With chrysin (chrys) and tectochrysin (tchrys), Ru(II) binds to the chromenone fragment to form cationic complexes that are isolated as [Ru(II)([9]aneS 3)(chrys)(DMSO)]Cl (2) and [Ru(II)([9]aneS 3)(DMSO)(tchrys)]Cl (3). The structure of the complexes is characterised by FT-IR, NMR and ESI+-MS. Furthermore, the flavones and the corresponding complexes, 1 – 3 , were investigated regarding their in vitro cytotoxic activity towards four different human tumour cell lines, PC-3 (prostate), MG-63 (osteosarcoma), MCF-7 and MDA-MB-231 (both breast adenocarcinoma). [ABSTRACT FROM AUTHOR]

Chalcones are bioactive molecules of natural and synthetic sources, whose physicochemical properties, reactivity, and biological activities are well-known among the scientific community. However, there are many molecules strictly related to chalcones with significantly less recognition like bis -chalcones. Several studies indicated that bis -chalcones have advantages over chalcones in specific bioactivities like anti-inflammatory activity. This review article describes the chemical structure and chemical properties of bis -chalcones, as well as the methods reported in the literature for the synthesis of these compounds highlighting the most recent developments. Finally, the anti-inflammatory activity of bis -chalcones is described, emphasizing the active structures found in literature and their mechanisms of action. [Display omitted] • Bis -chalcones are a subclass of chalcones that earned considerable interest. • Chemical synthesis of bis -chalcones based on established knowledge on chalcones. • Improvement of classic synthetic methodologies with new reaction conditions. • Very few bis- chalcones are associated with anti-inflammatory activity. • More studies on anti-inflammatory bis -chalcones are required to establish a SAR. [ABSTRACT FROM AUTHOR]

Abstract: Two new synthetic methodologies for 2,3-diarylacridin-9(10H)-ones were developed. The first one involves the Heck reaction of (E)-3-iodo-2-styrylquinolin-4(1H)-ones with styrenes, leading to (E,E)-2,3-distyrylquinolin-4(1H)-ones, which when heated at high temperatures cyclize in two different ways. Electrocyclization and further in situ oxidation leads to 2,3-diarylacridin-9(10H)-ones, while tautomerization, cyclization by nucleophilic addition and further in situ oxidation produces (E)-2-aryl-4-styrylfuro[3,2-c]quinolines as the main compound. The second method gives only 2,3-diaryl-10-methylacridin-9(10H)-ones and involves the Heck reaction of (E)-3-iodo-1-methyl-2-styrylquinolin-4(1H)-ones and styrenes, leading to (E,E)-1-methyl-2,3-distyrylquinolin-4(1H)-ones, which when heated at high temperatures cyclize through electrocyclization and oxidation processes affording the expected compounds. The structures of all new compounds were established by extensive NMR studies. [Copyright &y& Elsevier]

[Display omitted] • Serial PLS is used to develop regression models based on two different input data blocks. • 1H NMR and NIR spectral data combined improve the accuracy of estimations. • For 11 gasoline parameters, the error of estimations is within the reproducibility limits. The quality control of a commercial gasoline includes the assessment of several physical-chemical properties. The main objective of the present work is to investigate the simultaneous use of NIR and 1H NMR data to accurately estimate 13 of those characteristics [i.e., density, vapour pressure, percent evaporated at 70 °C, percent evaporated at 100 °C, percent evaporated at 150 °C, final boiling point, research octane number, motor octane number, aromatic content, olefinic content, benzene content, oxygen content and methyl t -butyl ether content]. The data driven models implemented in this work were single PLS using a concatenated block including two data types (i.e., NIR and 1H NMR), and serial PLS using the different data blocks separately. This work also aims at comparing the predictive capability of these regression models with the models calibrated with one type of spectroscopic data only. The optimum complexity of each model (i.e., number of latent variables) has been determined according to the repeated cross-validation strategy, consisting of 100 repetitions of a cross-validation loop. Serial PLS models have been proven effective in property estimation and, for most of the cases, outperform the models developed using a single spectroscopic technique. This proves the complementarity of both spectroscopic techniques, which are based on distinct principles. The developed models yielded accurate predictions of 11 of the 13 gasoline properties within the reproducibility of ISO standards. The implementation of these techniques in industry enables a significant reduction in the total time needed for gasoline quality control and the simultaneous use of two different spectroscopic techniques allows for more reliable estimations of the properties in study. [ABSTRACT FROM AUTHOR]

Highlights: [•] Genetic and abiotic factors influence phenolics production in Colocasia esculenta. [•] C. esculenta exhibits infraspecific chemical variability. [•] C. esculenta extracts are strong superoxide radical scavengers. [•] Wound healing may be due to oxidation and hyaluronic acid degradation prevention. [Copyright &y& Elsevier]

Abstract: The combination of (p-methoxyphenyl)imine, a bromonitroalkane, and zinc in the presence of catalytic indium allows straightforward access to β-nitroamine derivatives. The use of chiral sugar-derived imines furnished the corresponding β-nitroamines in high yields and stereoselectivities, from which the corresponding 1,2-diamines were easily obtained. The synthetic utility of the sugar-derived 1,2-diamines in the preparation of iminosugars was illustrated in a concise synthesis of 6-amino-1,6-dideoxynojirimycin. [Copyright &y& Elsevier]

Abstract: A novel synthetic method of carbohydrate derived vicinal aminoalcohols, from sugar aldehydes and bromonitroalkanes, has been developed. It involves an indium-catalyzed one-pot Henry reaction and nitro group reduction, and proceeds with a remarkably high anti-selectivity. The reaction of the intermediate aminoalcohols with alkylating agents furnished the corresponding carbohydrate-based tertiary aminoalcohols with excellent stereoselectivity. This very simple methodology allows easy access to families of N,N-dialkylated vicinal aminoalkanols, useful intermediates in the synthesis of derivatives of biological interest and sugar-based stereodifferentiating agents for asymmetric catalysis. [Copyright &y& Elsevier]

Abstract: The Diels–Alder reaction of (E)-2-styrylchromones with a pyrimidine ortho-quinodimethane is reported for the first time. These cycloaddition reactions afford mixtures of two regioisomeric tetrahydroquinazoline-substituted chromones in moderate to excellent global yields. Irrespective of the substituents on the 2-styrylchromones, the 2-(7-aryl-4-methoxy-2-methyl-5,6,7,8-tetrahydroquinazolin-6-yl)chromone derivatives are always the major isomers. [Copyright &y& Elsevier]

Abstract: The phenolic composition of the ethanolic extract obtained from the flowers of the medicinal plant Cytisus multiflorus has been elucidated by high performance liquid chromatography, electrospray mass spectrometry and nuclear magnetic resonance analysis. The extract was mainly composed of flavones, including the common chrysin, orientin, luteolin-5-O-glucoside, luteolin-7-O-glucoside, apigenin and apigenin-7-O-glucoside, which appeared as minor components. The major flavone in the extract was chrysin-7-O-β-d-glucopyranoside, and it also contained moderate amounts of a dihydroxyflavone isomer of chrysin, as well as of 2″-O-pentosyl-6-C-hexosyl-luteolin, 2″-O-pentosyl-8-C-hexosyl-luteolin and 6″-O-(3-hydroxy-3-methylglutaroyl)-2″-O-pentosyl-C-hexosyl-apigenin, which are not commonly found in the Fabaceae family. Other novel phenolic compounds found in the ethanolic extract of C. multiflorus comprised the flavones 2″-O-pentosyl-6-C-hexosyl-apigenin, 2″-O-pentosyl-8-C-hexosyl-apigenin and 6″-O-(3-hydroxy-3-methylglutaroyl)-2″-O-pentosyl-C-hexosyl-luteolin. The assessment of the biological activities of the main compounds of this extract are now keen, in order to determine their relevance in the beneficial properties of the plant. [Copyright &y& Elsevier]

Abstract: The state of the art in the characterization of heavy crude oil mixtures is presented. This characterization can be done by different techniques, such as gas chromatography (GC), high performance liquid chromatography (HPLC), thin layer chromatography (TLC), infrared spectroscopy (IR), Raman spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Nuclear magnetic resonance spectroscopy is the technique of choice due to its capability to provide information on the chemical nature of individual types of hydrogen and carbon atoms in different and complex mixtures of crude oils. The progress made in the interpretation of the NMR spectra with the development of new NMR techniques and different multivariate data analyses could give relevant information about the identification and characterization of hydrocarbons and their physical and chemical properties. These progresses can improve the refining industries operation as a result of the better knowledge on the crude composition that is fed in the refining process, as well as in the prediction of better operating conditions to obtain refined products with desired specifications and in quantities desirable to meet the market demands. The improvement in the refining operation conditions is reflected in economical benefits. [Copyright &y& Elsevier]

Abstract: A new group of pyranoanthocyanin-derived polyphenolic compounds was recently found to occur in aged wines and named as oxovitisins, the spectrum of which displayed only a pronounced broad absorption peak around 370nm in the UV region, being quite different from that of anthocyanin-like chromenylium pigments which present maximum absorption in the visible wavelength ranges. The possibilities and reaction conditions for the oxidative transformation of anthocyanin type flavylium cations into new type of stable pyranone structures of non-oxonium nature was studied through two-step reactions using anthocyanins obtained from different fruit extracts. The irreversible change of pyranoflavyliums to the neutral pyranone compounds by hydration and further oxidation reactions in the second step were strongly related to pH. The reaction took place only in mildly acidic solutions with the most favourable pH range 4.0–5.5, as the hemiacetal formation by the nucleophilic attack of water could be hindered at higher or lower pH. The reaction rate increased significantly with increasing temperature. The new non-oxonium compounds resulting from malvidin-3-coumaroylglucoside and cyanidin-3-rutinoside were structurally characterised by MS and NMR spectroscopy and shown similarly to possess the common α-pyranone (lactone) ring between C-4 and the hydroxy group at C-5 of the anthocyanin core, which confers them with unique spectrum characteristics. The interest in new anthocyanin derivatives of non-oxonium nature with additional pyranone (lactone) ring will go beyond wine chemistry and bring expectations concerning their use in the food and pharmaceutical industry due to their spectral and structural similarity to flavones as well as their naturally occurring nature. [Copyright &y& Elsevier]

Abstract: It is shown that the relationship between the alkyl chain length of 3-alkyl-3′,4′,5,7 tetrahydroxyflavones (FnH) bearing alkyl chains of n =1, 4, 6, 10 carbons and their capacity to counter oxidative damage varies markedly with the nature of the biological system. In Cu2+-induced lipid peroxidation of low-density lipoprotein (LDL), the less hydrophobic short-chain F1H and F4H are probably located in the outer layer of LDL and parallel the reference flavonoid antioxidant, quercetin (Q) as effective inhibitors of lipid peroxidation. A marked inhibition of haemolysis induced in red blood cells (RBC) suspensions by the membrane-permeant oxidant, tert-butylhydroperoxide (t-BuOOH), is observed with F4H and F6H present at concentration in the micromolar range. However, F10H the most hydrophobic FnH is even more effective than Q against both haemolysis and lipid peroxidation as measured by malondialdehyde (MDA) equivalents. In oxidation of RBC by H2O2, at least 50 times more F6H and F10H than by t-BuOOH are required to only partly inhibit haemolysis and MDA production. The F1H, F4H and Q are found rather inactive under these conditions. At concentrations in the micromolar range, a marked protection against the cytotoxic effects of the t-BuOOH-induced oxidative stress in human skin NCTC 2544 keratinocytes is also exhibited by the four FnH antioxidants and is comparable to that of Q. Thus, the four FnH species under study may be considered as potent antioxidants which manifest complementary anti-oxidative actions in biological systems of markedly different complexity. [Copyright &y& Elsevier]

Abstract: A simple synthesis of new amphiphilic chlorin derivatives from protoporphyrin-IX dimethyl ester is reported. The preparation of such compounds is based in a straightforward methodology, which involves the Diels–Alder reaction of protoporphyrin-IX dimethyl ester with maleic anhydride followed by addition of nucleophilic species to the initially formed cycloadducts, a transformation, which is highly regioselective. Preliminary photophysical studies with the new compounds show that they meet adequate features for PDT applications. [Copyright &y& Elsevier]

Abstract: The dichloromethane extract from leaves of Juniperus brevifolia, through chromatographic fractionations yield six compounds: 3β-hydroxy-abieta-8,11,13-trien-7-one, 18-hydroxy-sandaracopimara-8(14),15-dien-7-one, sandaracopimara-8(14),15-dien-18-yl formate; and the first examples of sandaracopimaranes and abieta-8,11,13-triene diterpenoids with a large aliphatic chain on C-18, abieta-8,11,13-trien-18-yl hexadecanoate, 7-oxoabieta-8,11,13-trien-18-yl hexadecanoate, sandaracopimara-8(14),15-dien-18-yl hexadecanoate. Moreover fifteen known compounds were also isolated, some of them for the first time identified on Juniperus genus. The compound abieta-8,11,13-trien-18-yl formate is reported for the first time as a natural product. All the structures were established by spectroscopic methods. 2D NMR techniques have allowed the revision of certain previously reported 13C NMR assignments. Studies on the isolated new compounds showed those possessing a diterpenol ester of a long-chain fatty acid present lipophilicity very distinct from other diterpenoid compounds. [Copyright &y& Elsevier]

Abstract: An efficient synthetic method for the preparation of (E)- and (Z)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles has been developed. The reaction of (E)- and (Z)-3-styrylchromones with hydrazine hydrate afforded the corresponding (E)- and (Z)-4-styrylpyrazoles, respectively, saved 4′-nitro-derivatives where both (E)- and (Z)-4′-nitro-3-styrylchromones afforded (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles. The reaction mechanism for these transformations was discussed and the stereochemistry of all products was assigned by NMR experiments. [Copyright &y& Elsevier]

The synthesis of several 2′-hydroxynitrochalcones has been accomplished by an aldol reaction of equimolar amounts of the appropriate 2′-hydroxyacetophenones with nitrobenzaldehydes in alkaline medium. The reaction of 2′-hydroxyacetophenones bearing a 6′-methoxy with 2- or 4-nitrobenzaldehydes gave the expected 2′-hydroxynitrochalcones and also 4-methoxynitroaurones, being the latter ones the unique reaction products when using 2 molar equiv of nitrobenzaldehydes. The reaction mechanisms for the formation of both products are discussed. The 13C NMR chemical shifts have been discussed first by means of an empirical additive model and then by comparison with GIAO/B3LYP calculated absolute shieldings. [Copyright &y& Elsevier]

Four polyhydroxylated 2-styrylchromones, structurally related to flavones and cinnamic acid, have been studied. An SC derivative with OH groups only at positions 3′ and 4′ on the styryl moiety and another SC bearing an additional OH group at position 5 on the benzopyrone ring were more potent inhibitors of the Cu2+-induced peroxidation of LDL than the flavonoid quercetin. Fluorescence and absorption spectroscopies suggested that one LDL particle may bind 40 SC molecules. A pulse radiolysis study in pH 7 buffered micellar solutions of neutral TX100 and positively charged CTAB demonstrated that one-electron oxidation by ⋅Br2-, ⋅O2- and tryptophan radicals (⋅Trp) depends strongly on the micellar microenvironment. All SCs were readily oxidized by ⋅O2- in CTAB micelles (rate constants: 6–18×106 M-1 s-1). In TX100 micelles only the SC derivative with OH groups in position 3′ and 4′ reacted with ⋅O2- (rate constant: 1.1×106 M-1 s-1). In CTAB, electron transfer to ⋅Trp radicals was observed for all SCs with rate constants ≥3.2×107 M-1 s-1. In TX100 micelles, this reaction occurred solely with the derivative bearing OH groups only at positions 3′ and 4′. [Copyright &y& Elsevier]

A one-pot synthesis of novel 2-(2-hydroxyaryl)quinolines have been developed from the intramolecular reductive coupling reactions of 2′-hydroxy-2-nitrochalcones, induced by stannous chloride in acidic medium (HCl/AcOH). In some cases these transformations can be performed with ammonium formate/Pd–C in methanol. [Copyright &y& Elsevier]

An arabinan (97% of Ara and 3% of hexuronic acid) was isolated from the alcohol-insoluble residue (AIR) of olive pomace by treatment with 0.02 M HNO3, at 80 °C, followed by graded precipitation with ethanol. It was separated from acidic pectic polysaccharides by anion-exchange chromatography, and by size-exclusion chromatography its molecular weight was estimated as 8.4 kDa. By methylation analysis, the linkage composition was established as 5:4:3:1 for (1→5)-Araf, T-Araf, (1→3,5)-Araf and (1→3)-Araf, respectively. 13C NMR spectroscopy confirmed this linkage composition, and allowed to assign the α anomeric configuration for the arabinofuranosyl residues, except for some terminally linked ones, that were seen to occur as T-β-Araf. By 2D NMR spectroscopy (1H and 13C), it was possible to conclude that the T-β-Araf was (1→5)-linked to a (1→5)-Araf residue. Also, in the arabinan (1→5)-Araf backbone, the branched (1→3,5)-Araf residues were always adjacent to linear (1→5)-Araf residues. A tentative structure is proposed. [Copyright &y& Elsevier]

Tetrakis(1 H -pyrazol-1-yl)methanes are very rare compounds of which only two are known: the unsubstituted 1 obtained classically by Hückel in 1937 from carbon tetrachloride and prepared again several times and the 3,5-dimethyl substituted 2 obtained serendipitously by Pombeiro in 2009. We have now extended this group to include four new derivatives 8 , 9 , 11 and 12 bearing methyl groups. The X-ray crystal structure of the four compounds has been determined. They have been studied by NMR both in solution (1H, 13C, 15N) and in the solid state (13C and 15N). DFT calculations of the six compounds (geometries, energies and absolute shieldings) have been used to discuss the experimental observations. Image 1 • Tetrakis(pyrazol-1-yl)methanes a family of ligands where only two members were known. • Four new examples of tetrakis(pyrazol-1-yl)methanes were prepared and characterized. • X-ray structures and 1H, 13C, 15N NMR (solution, solid state) were recorded. • B3LYP/6–311++G(d,p) calculations on geometries, energies, NMR were carried out. • Use of a polynomial expression (a+b)n to rationalize the different isomers failed. [ABSTRACT FROM AUTHOR]

• Hydrophobic polysaccharides were isolated from apple pomace. • Pectin-polyphenol-xyloglucan and arabinan-polyphenol complexes were identified. • Polysaccharide-polyphenol complexes are formed during apple processing. • Oxidized polyphenols are covalently bonded to polysaccharides in apple pomace. • Covalently bonded polyphenols modulate polysaccharides hydrophobicity. In this work, polysaccharides extracted with hot water from apple pomace were isolated by C18 cartridge solid-phase extraction at pH 7 (Fr7). Dialysis (12–14 kDa) of this fraction allowed to obtain 17% (w/w) of polymeric material composed by 65% of polysaccharides, mainly arabinose (58 mol%), galacturonic acid (16 mol%) and glucose (10 mol%). Folin-Ciocalteu assay showed 62 g of phloridzin equiv/kg of polyphenols. Moreover, adjusting to pH 3, it was possible to retain an additional fraction (Fr3) representing a further 4% of the polymeric material. Fr3 contained 53% of polysaccharides composed mainly by galacturonic acid (66 mol%) and polyphenols accounted for 37 g of phloridzin equiv/kg. Precipitation with ethanol and subsequent methylation and NMR spectroscopic analysis of Fr7 dialysate allowed the identification of covalently-linked pectic-polyphenol-xyloglucan and arabinan-polyphenol complexes. These structures are possibly formed as a result of polyphenol oxidation reactions during the industrial processing of apples, conferring hydrophobic characteristics to apple pomace polysaccharides. [ABSTRACT FROM AUTHOR]

The contamination and bioavailability of deleterious metals in arable soils significantly limits crop development and yield. Aiming at mitigating Pb- and Al-induced phytotoxicity, this work explores the use of P25 titanium dioxide nanoparticles (nTiO 2) in soil amendments. For that, Lactuca sativa L. plants were germinated and grown in the presence of 10 ppm Pb or 50 ppm Al, combined or not with 5 ppm nTiO 2. Growth parameters, as well as endpoints of the redox state [cell relative membrane permeability (RMP), thiobarbituric acid reactive substances content, total phenolic content and photosynthesis (sugars and pigments levels, chlorophyll a fluorescence and gas exchange), were evaluated. Concerning Al, nTiO 2 treatment alleviated the impairments induced in germination rate, seedling length, water content, RMP, stomatal conductance (g s), intercellular CO 2 (C i), and net CO 2 assimilation rate (P N). It increased anthocyanins contents and effective efficiency of photosystem II (Φ PSII). In Pb-exposed plants, nTiO 2 amendment mitigated the effects in RMP, P N , g s , and C i. It also increased the pigment contents and the transpiration rate (E) comparatively to the control without nTiO 2. These results clearly highlight the high potential of low doses of nTiO 2 in alleviating metal phytotoxicity, particularly the one of Pb. Additionally, further research should explore the use of these nanoparticles in agricultural soil amendments. • nTiO 2 low levels application mitigate Al- and Pb-induced phytotoxicity. • nTiO 2 interacted antagonistically with Al and Pb. • In Al-exposed plants, nTiO 2 improved growth and gas exchange. • nTiO 2 alleviated Pb-induced impairments in gas exchange and pigment contents. [ABSTRACT FROM AUTHOR]

Commercial gasoline must satisfy several product specifications before trading. In the present work, repeated double cross validation using partial least squares regression was applied to create reliable prediction models for 13 physicochemical parameters (eg, density, vapour pressure, evaporate at 70°C, evaporate at 100°C, evaporate at 150°C, final boiling point, research octane number, motor octane number, aromatic content, olefinic content, benzene content, oxygen content, and methyl tert‐butyl ether content) of gasoline produced in Matosinhos' refinery. The input variables for the regression are the 1H NMR spectral intensities of a total of 448 samples, which were recorded using a picoSpin NMR spectrometer operating at 80 MHz. The output variables are the corresponding property values, which were also measured according to ISO standard methods. A spectral feature elimination before multivariate analysis was done to remove noise and speed up the chemometric analysis. The optimum complexity of each model was achieved by repeated double cross‐validation strategy, consisting of 100 repetitions of two nested cross‐validation loops. Quantitative partial least squares yielded accurate predictions of 11 of 13 properties within the reproducibility of ISO standards. The methodology presented in this work has been proven effective in property estimation and enables a significant reduction in the total time of gasoline quality control. Repeated double cross validation using partial least squares regression was implemented to calibrate reliable models for the estimation of 13 physicochemical parameters of gasoline from 1H NMR data. Quantitative models yielded accurate predictions of 11 of 13 properties within the reproducibility of ISO standards and consequently the implemented metodology has been proven effective in property estimation. [ABSTRACT FROM AUTHOR]

Combination of the calculation of reactivity descriptors and the cold iodine test for some coumarin derivatives was used in order to optimize the radioiodination reaction. The strongly nucleophilic predicted coumarins were subjected to the action of cold iodine. With two coumarins substituted at 3 by the 2-hydroxybenzoyl group, iodination did not occur but a product of intramolecular heterocyclization was obtained. This strategy is useful for economic and environmentally friendly radioiodination. Combination of the calculation of reactivity descriptors and the cold iodine test for some coumarin derivatives in order to optimize the radioiodination reaction. The strongly nucleophilic predicted coumarins were subjected to the action of cold iodine. With two coumarins substituted at 3 by the 2-hydroxybenzoyl group, iodination did not occur but a product of intramolecular heterocyclization was obtained. This strategy is useful for economic and environmentally friendly radioiodination. Image 1 • The calculation of global and local nucleophilicity parameters for coumarin derivatives. • Iodination tests with cold iodine and analysis of the compounds obtained. • The iodonium cation causes intramolecular heterocyclization without iodination. • The combination of theoretical calculations - cold iodine is a useful strategy. [ABSTRACT FROM AUTHOR]

Highlights • Roots and shoots of dill are affected when grown under bicarbonate-induced Fe deficiency. • Shoot biomass was decreased whereas that of roots was not affected. • Reduction of chlorophyll and Fe concentration were registered. • Although distinct polyphenols were found in the plant organs, they were all increased. • This was paralleled by an increment of antioxidant capacity. Abstract This study aimed to investigate the effects of bicarbonate-induced iron deficiency on growth, photosynthetic performance, secondary metabolite content, and related antioxidant capacity in seedlings of Anethum graveolens (L.) grown under controlled conditions in the presence of iron (+Fe) or in induced-iron deficient (+Fe + Bic) media. The main results have shown that dill shoot and plant biomass production significantly decreased under Fe deficiency conditions, whereas that of roots was not affected by such constraint. Moreover, Fe deficiency resulted in a significant reduction of chlorophyll and Fe concentration. Interestingly, when grown under Fe deficiency conditions, A. graveolens was able to increase its shoot iron use efficiency (FeUE). In addition, levels of individual and of total phenolic compounds were shown to be raised in roots as well in leaves. This fact was accompanied by an increased antioxidant activity, as measured through distinct in vitro methods (ABTS+, O 2 −, HO, FRAP and ORAC). The overall data suggests that A. graveolens was able to maintain plant growth and to preserve adequate chlorophyll synthesis under iron-limiting conditions, probably due to its better Fe-use efficiency. The species was also able to modulate secondary metabolites metabolism and its antioxidant capacity, in order to minimize the deleterious effects of reactive oxygen species. [ABSTRACT FROM AUTHOR]

Abstract Carotenoids are lipid soluble plant pigments that make part of human daily diet. These compounds are able to react with diverse reactive species and originate a myriad of oxidation products that have similar or even more reactivity than their parent compounds. These products may be short-chain carbonyl compounds and, the commonly designated, apo-carotenoids. The effects fo these products in the human body are not yet fully understood, but it is believed that they are intimately related with their oxidative potential. As so, carotenoids and their oxidation products have undeniable potential as bioactive compounds. However, the multifactorial elements that influence their activity/reactivity make really hard, or probably impossible, the task to classify them as anti- or pro-oxidant compounds. This manuscript provides a thorough review on the reactions of carotenoids with the most physiologically relevant reactive oxygen and nitrogen species, and scrutinizes the resulting oxidation products that have been hitherto identified. Finally, the dual anti- vs. pro-oxidant activities of carotenoids are discussed, mostly based on studies which use physiologic relevant reactive species in oxidative stress. Definitely, there is an open window to the development of deeper studies in this field with a greater number of carotenoids, especially with the ones hitherto not studied. Graphical abstract Image 1 Highlights • Carotenoids' classification, structure, occurrence, and ADME. • Review on carotenoids' reaction with physiologically relevant reactive oxygen and nitrogen species. • Anti- versus pro-oxidant activities of carotenoids and their oxidation products are influenced by multifactorial elements. • Future focus: define the exact conditions that make carotenoids and their oxidative products profitable anti- or pro-oxidants. [ABSTRACT FROM AUTHOR]

Abstract A general and highly selective method for the synthesis of carbohydrate-derived ( Z )-vinyl halides and silanes is described. This reaction takes place through a β-elimination process of sugar-derived α-halomethylcarbinol acetates promoted by samarium diiodide. Starting materials have been easily prepared in two steps consisting in an initial addition of halomethyllithium compounds to the corresponding galactose-derived aldehyde, followed by acetylation. A mechanism that explains both the formation of ( Z )-vinyl derivatives and its selectivity is proposed. Finally, the synthetic usefulness of these compounds has been applied in cross-coupling reactions with ethynyl benzene towards the formation of selected enyne derivatives. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

The search of new antioxidants, as drugs candidates, is an active field of medicinal chemistry. The synthesis of compounds with antioxidant potential has increased in recent years and a high number of structurally diverse compounds have been published. This review aims to show the current state-of-the-art on the development of antioxidant compounds incorporating the pyrazole pharmacophore. It is a well-timed review driven by the increasing number of papers, on this issue, that have been published since the beginning of the 21st century (from 2000 to 2017). The aim is to look deeper into the structures already published in the literature containing the pyrazole core as the unique pharmacophore or combined with other pharmacophores and see the relationship between the presence of this five-membered nitrogen heterocycle and the behaviour of the compounds as potential antioxidant agents. An attempt was made to whenever possible establish structure-activity relationships that could help the design of new and more potent antioxidant agents containing this important pharmacophore. [ABSTRACT FROM AUTHOR]

Nine Tunisian Thymus capitatus (L.) Hoff. et Link. populations harvested in six bioclimatic zones extending from the sub humid (550 mm rainfall/year) to the lower arid (96.3 mm rainfall/year), and grown at altitudes ranging from 60 to 600 m were assessed for their phenolic composition. The identification of phenolic compounds was revealed by UHPLC-DAD-ESI/MS n . 11 phenolic compounds including three phenolic acids (rosmarinic acid, salvianolic acid A, salvianolic acid E), three flavanones (hesperidin, eriodictyol and naringenin), two C-glycoside isomers of the flavone apigenin, one flavanol gallocatechine, one flavanonol taxifolin and one phenolic monoterpen (carvacrol) were identified. Differences in phenolic composition among populations, in relationship with altitudes and/or annual rainfall were shown. Higher amounts of total phenols, total flavonoids, rosmarinic acid and carvacrol were detected in samples from the most arid zones (96.3–167 mm rainfall/year) in comparison with populations located in wet lands (450–660 mm rainfall/year). The altitude within or between contiguous climates is a main factor influencing phenol compounds content. The chemical variation among the populations should lead to the selection of plants with high potential in order to use them in health care and food industry. [ABSTRACT FROM AUTHOR]

To study structure-function relationships of pectic polysaccharides with their immunostimulatory activity, broccoli by-products were used. Pectic polysaccharides composed by 64 mol% uronic acids, 18 mol% Ara, and 10 mol% Gal, obtained by hot water extraction, activated B lymphocytes in vitro (25–250 μg/mL). To disclose active structural features, combinations of ethanol and chromatographic fractionation and modification of the polysaccharides were performed. Polysaccharides insoluble in 80 % ethanol (Et80) showed higher immunostimulatory activity than the pristine mixture, which was independent of molecular weight range (12–400 kDa) and removal of terminal or short Ara side chains. Chemical sulfation did not promote B lymphocyte activation. However, the action of pectin methylesterase and endo -polygalacturonase on hot water extracted polysaccharides produced an acidic fraction with a high immunostimulatory activity. The de-esterified homogalacturonan region seem to be an important core to confer pectic polysaccharides immunostimulatory activity. Therefore, agri-food by-products are a source of pectic polysaccharide functional food ingredients. [Display omitted] • Pectic polysaccharides from broccoli by-products activate B lymphocytes. • Immunostimulation do not rely on terminal arabinose and molecular weight. • Chemical sulfation does not impact immunostimulatory activity. • De-esterified homogalacturonan regions are an important core for activity. [ABSTRACT FROM AUTHOR]

We have performed a study of structural, thermochemical and thermophysical properties of the ( Z )-cinnamic acid neutral molecule and its corresponding oxyanion (formed by deprotonation of the carboxylic group). The thermophysical study (heat capacities, temperature and enthalpy of fusion) was made by DSC. The following intrinsic (gas-phase) thermochemical magnitudes have been experimentally determined: (i) standard enthalpy of formation, at T = 298.15 K, of the neutral molecule, Δ f H m 0 (g) = (−215.5 ± 3.2) kJ · mol −1 , by combustion calorimetry and by the Knudsen effusion technique, (ii) deprotonation enthalpy, Δ acid H 0 (g) = (1416.4 ± 8.8) kJ · mol −1 and acidity, GA = (1386.7 ± 8.8) kJ · mol −1 , by the EKM method using ESI-TQ Mass Spectrometry. From these results we have also derived the enthalpy of formation of the oxyanion, Δ f H m 0 (oxyanion, g) = (−303.5 ± 9.4) kJ · mol −1 . A computational study, through density functional calculations at the B3LYP/6-311++G(d,p) level of theory, was used to check the good consistency of the experimental results. The global results show that ( Z )-cinnamic acid is significantly less stable than the corresponding ( E )-isomer, which can be related to the greater acidity of the ( Z )-form found in both the gas and aqueous solution phases. [ABSTRACT FROM AUTHOR]

Solution-state 1 H NMR spectroscopy was applied to characterize the structural features of water- and alkaline-soluble organic matter (WSOM and ASOM, respectively) sequentially extracted from fine urban atmospheric aerosols collected over different seasons. The objectives of this study were twofold: (i) to compare the functional characteristics of fine aerosol WSOM and the yet unknown ASOM, and (ii) to assess the sources of WSOM and ASOM at an urban location. The 1 H NMR analysis confirmed that the WSOM and ASOM fractions hold similar 1 H functional groups; however, they differ in terms of their relative distribution throughout the seasons. The winter and autumn samples have a less aliphatic and oxidized character and higher contributions from aromatic groups than those of warmer conditions. The urban aerosol WSOM and ASOM fractions do not fit the established 1 H NMR source apportionment fingerprints of marine, secondary, and biomass burning organic aerosols (OAs), exhibiting a smaller relative contribution of carbon-oxygen double bonds, which is indicative of a less oxidized character. These results confirm that the boundaries of the pre-established source categories, especially for secondary and biomass burning OAs, might be different at urban locations, suggesting the need to improve the 1 H NMR source apportionment model for including a new fingerprint for urban OAs. [ABSTRACT FROM AUTHOR]

The synthesis of ( E )-2-aryl-1-methyl-3-styrylquinolin-4(1 H )-ones, through the Heck reaction of 2-aryl-3-iodo-1-methyl-quinolin-4(1 H )-ones with styrene is described. 2-Aryl-3-iodo-1-methyl-2-quinolin-4(1 H )-ones can be obtained efficiently in a two-step transformation, methylation followed by in situ cyclization of N -(2-acetylphenyl)benzamides into 2-aryl-1-methylquinolin-4(1 H )-ones, which underwent selective 3-iodination with iodine and a catalytic amount of Can. Cyclisation studies of ( E )-2-aryl-1-methyl-3-styrylquinolin-4(1 H )-ones under high temperature or photoinduced electrocyclisation lead to 4-aryl-2-phenylfuro[3,2- c ]quinolines and 12-methyl-5-phenylbenzo[ c ]acridin-7(12 H )-ones. [ABSTRACT FROM AUTHOR]

Elevated levels of prostaglandin E 2 have been implicated in the pathophysiology of various diseases. Anti-inflammatory drugs that act through the inhibition of cyclooxygenase enzymatic activity, thereby leading to the suppression of prostaglandin E 2 , are often associated with several side effects due to their non-specific inhibition of cyclooxygenase enzymes. Consequently, the targeted suppression of prostaglandin E 2 production with innovative molecules and/or mechanisms emerges as a compelling therapeutic strategy for the treatment of inflammatory-related diseases. Therefore, in this study, a systematic analysis of 28 pyrazole derivatives was conducted to explore their potential mechanisms for reducing prostaglandin E 2 levels. In this context, the evaluation of these derivatives extended to examining their capacity to reduce prostaglandin E 2 in vitro in human whole blood, inhibit cyclooxygenase-1 and cyclooxygenase-2 enzymes, modulate cyclooxygenase-2 expression, and suppress oxidative burst in human leukocytes. The results enabled the establishment of significant structure-activity relationships, elucidating key determinants for their activities. In particular, the 4-styryl group on the pyrazole moiety and the presence of chloro substitutions were identified as key determinants. Pyrazole 8 demonstrated the capacity to reduce prostaglandin E 2 levels by downregulating cyclooxygenase-2 expression, and pyrazole-1,2,3-triazole 18 emerged as a dual-acting agent, inhibiting human leukocytes' oxidative burst and cyclooxygenase-2 activity. Furthermore, pyrazole 26 demonstrated effective reduction of prostaglandin E 2 levels through selective cyclooxygenase-1 inhibition. These results underscore the multifaceted anti-inflammatory potential of pyrazoles, providing new insights into the substitutions and structural frameworks that are beneficial for the studied activity. [Display omitted] • Pyrazoles effectively inhibited PGE 2 , COX and leukocytes' oxidative burst. • 4-(Chlorostyryl) group favored inhibition of COX-2 and leukocytes' oxidative burst. • Triazole 18 inhibits leukocytes' burst and COX, with potential COX-2 selectivity. • Pyrazole 26 reduced PGE 2 levels through selective COX-1 inhibition. • Pyrazole 8 downregulated COX-2 expression. [ABSTRACT FROM AUTHOR]

Two new Δ1-pyrroline ligands and their corresponding boron complexes have been synthesized and characterized. Their luminescent properties were investigated, the boron complexes emitting brightly around 410 nm. The presence of the exocyclic double bond has no influence on their electronic properties, meaning that this part of the complex could be used to fine tune their properties without disturbing their fluorescence. [ABSTRACT FROM AUTHOR]

Thymus x citriodorus is a Lamiaceae plant extensively cultivated in the Mediterranean region and used for centuries in culinary and in traditional medicine. The present work describes the detailed phenolic composition of T. x citriodorus for the first time, by means of HPLC–DAD, ESI–MS and MSn and nuclear magnetic resonance (NMR) analyses. The ethanolic extract of T. x citriodorus was analyzed by reversed phase HPLC. The method of analysis was also validated concerning its linearity, instrumental and method precision (for repeatability, immediate precision and intermediate precision) and accuracy (absolute recovery study). The technique was combined with electrospray mass spectrometry in order to identify the phenolic compounds and the structure of the main phenolics was also confirmed by NMR analysis. The in-house validated HPLC–DAD method showed good linearity for the tested reference compounds as well as satisfactory repeatability and immediate precision values, for both instrument and method. Furthermore, the satisfactory results of intermediate precision analysis and recovery assays indicated that the chromatographic method could be used to quantify the main phenolic compounds of T. x citriodorus with adequate precision and accuracy. The extract was rich in rosmarinic acid (10.4±0.6mg/g extract) that is a widespread phenolic acid in Thymus plants, but also in luteolin-7-O-α-glucuronide (12±2mg/g extract), that was herein reported in Thymus for the first time. Other novel compounds comprised one eriodictyol dihexoside with O-glycosidic linkages, two eriodictyol-O-monohexosides, one quercetagetin dimethyl ether-O-hexoside, one naringenin-O-hexoside and chrysoeriol-7-β-O-glucoside. Having in mind the health-promoting properties reported in literature for some of the main polyphenols found in T. x citriodorus, we suggest that this plant has a high potential for being used as a functional food. [ABSTRACT FROM AUTHOR]

Abstract: A family of diphenylmethane derivatives has been synthesized and their luminescence properties characterized. While in solution the compounds are weakly emissive, showing no aggregation-induced emission enhancement, the crystals of three dialkyl 5,5′-methylenebis(2-hydroxybenzoate) samples exhibit intense emission. This emission enhancement upon crystallization is ascribed to particular molecular packing, which stiffens the structure of the compounds via hydrogen bonds, preventing consecutive π–π interactions. [Copyright &y& Elsevier]

Abstract: A new synthesis of a tetrahedral tecton, tetrakis(4-methoxyphenyl)methane, is reported. This compound exhibits a strong fluorescence around 340nm at room temperature, both in solution and in the solid state. Upon crystallization, another luminescence band can be observed around 500nm, attributed to phosphorescence. A study of the single-crystal structure of the compound provided a rationalization of this crystallization induced phosphorescence. The crystal of tetrakis(4-methoxyphenyl)methane belongs to the tetragonal space group P 21 c, and the structural analysis revealed a close packing of the molecules, with no void space and no solvent molecules in the crystal. The molecules are held together in a columnar array via multiple C–H⋯π hydrogen bonds. The hydrogen bonds between the molecules impede the torsional vibrations of the aromatic rings, preventing thermal relaxation from the triplet state, and hence promoting phosphorescence at room temperature. [Copyright &y& Elsevier]

Abstract: Bis(3-bromo-4-dimethylaminobenzylidene)hydrazine and bis(3-chloro-4-dimethylaminobenzylidene)hydrazine have been synthesized, and their monoclinic crystal structures solved in space group P21/c. For the bromo derivative at 150K, a =10.4505(2), b =8.0358(2), c =11.3208(2)Å, β =102.56(2)°, Z =2, V =927(9)Å3, Dx =1.618gcm−3, refinement on 2217 reflections, R =0.023. For the chloro derivative at 150K, a =10.3416(8), b =8.0605(5), c =11.1573(8)Å, β =102.70(8)°, Z =2, V =907(3)Å3, Dx =1.330gcm−3, refinement on 2429 reflections, R =0.038. The molecules are close to planar, the crystal packing shows Br⋯Br or Cl⋯Cl intermolecular halogen bonds, and some CBr or Cl contacts. There are no Cl⋯N or Br⋯N interactions. [Copyright &y& Elsevier]

Abstract: The present study reports the electrochemical behavior of several phenolic and catecholic-substituted 2,3-diarylxanthones on a glassy carbon electrode, challenged by cyclic voltammetry at different pH values (4.0, 7.4, and 11.0). Higher pH values required lower anodic and cathodic peak voltages. The oxidation of catecholic groups occurred at lower peak potentials in a reversible and pH dependent manner. Anodic peak potentials appeared at higher pH values and were attributed to the electrochemically irreversible oxidation of the phenolic groups. The number and position of hydroxyl substituents were the determinants for the electrochemical behavior and found to correlate with the scavenging activity for reactive oxygen (ROS) and nitrogen species (RNS). A xanthone with two catechol units presented the lowest anodic potential voltage (E pa =0.15V) and proved to be the most effective ROS and RNS scavenger. [Copyright &y& Elsevier]

Lamium album L. is an edible plant which is consumed raw or cooked, in particular in the Mediterranean and surrounding areas. It is also consumed as tea infusions and as a main component of food supplements, because of its pharmacological effects. Despite being consumed by humans for centuries, the chemical composition of L. album L. is far from being understood. In this study, a purified ethanolic extract (PEEL) was prepared and further analyzed by high performance liquid chromatography and electrospray mass spectrometry. Overall, verbascoside accounted for approximately half of the phenolic content of the extract, but this also contained other bioactive phenolic compounds herein detected for the first time in the genus, namely isoscutellarein derivatives. The latter included isoscutellarein-7- O -allosyl(1 → 2)glucoside, its O -methyl derivative, three acetyl derivatives of isoscutellarein- O -allosyl glucoside and one acetylated form of O -methylisoscutellarein-7- O -allosyl(1 → 2)glucoside. From those, the main isoscutellarein derivative was assigned to isoscutellarein-7- O -(6- O -acetyl-β-allosyl)(1 → 2)-β-glucoside, as confirmed by NMR. Altogether, isoscutellarein derivatives accounted for almost 30% of PEEL phenolics. Since verbascoside and isoscutellarein derivatives are main components of L. album L. ethanolic extract, their possible association to the health benefits of the plant is discussed. [ABSTRACT FROM AUTHOR]

Abstract: The viscosity index (VI) is a useful tool for lubricant users and refiners, since it is a measure of the effect of temperature changes on the viscosity of the oil. However, it was found that the viscosity index does not correlate with the flow activation energy Ea , which is the theoretically defined dependence of the viscosity on temperature. In this way, two oils may have the same flow activation energy but a viscosity index varying by up to 120. We therefore believe that the VI does not always give a proper representation of the effect of temperature on the kinematic viscosity. 13C NMR spectroscopy was used to identify the molecules with a high VI. Twenty different oil samples produced from eight different vacuum gas oils with viscosity indices ranging from −104 to 146 were analyzed and key parameters identified for high VI molecules: long alkyl chains, methyl branching in the centre of the molecule, low content of aromatic compounds, no ethyl branching and no tertiary carbons. A correlation based on four selected peaks was developed, giving a very good prediction of the viscosity index. [Copyright &y& Elsevier]

Abstract: Cyclooxygenases (COXs) are the key enzymes in the biosynthesis of prostanoids. COX-1 is a constitutive enzyme while the expression of COX-2 is highly stimulated in the event of inflammatory processes, leading to the production of large amounts of prostaglandins (PGs), in particular PGE2 and PGI2, which are pro-inflammatory mediators. Lipoxygenases (LOXs) are enzymes that produce hydroxy acids and leukotrienes (LTs). 5-LOX metabolizes arachidonic acid to yield, among other products, LTB4, a potent chemoattractant mediator of inflammation. The aim of the present work was to evaluate the anti-inflammatory potential of 2-styrylchromones (2-SC), a chemical family of oxygen heterocyclic compounds, vinylogues of flavones (2-phenylchromones), by studying their COX-1 and COX-2 inhibitory capacity as well as their effects on the LTB4 production by stimulated human polymorphonuclear leukocytes (PMNL). Some of the tested 2-SC were able to inhibit both COX-1 activity and LTB4 production which makes them dual inhibitors of the COX and 5-LOX pathways. The most effective compounds in this study were those having structural moieties with proved antioxidant activity (3′,4′-catechol and 4′-phenol substituted B-rings). This type of compounds may exhibit anti-inflammatory activity with a wider spectrum than that of classical non-steroidal anti-inflammatory drugs (NSAIDs) by inhibiting 5-LOX product-mediated inflammatory reactions, towards which NSAIDs are ineffective. [Copyright &y& Elsevier]

Abstract: The hot water soluble green coffee arabinogalactans, representing nearly 7% of total coffee bean arabinogalactans, were characterized by 1H and 13C NMR and, after partial acid hydrolysis, by ESI-MS/MS. Data obtained showed that these are highly branched type II arabinogalactans covalently linked to proteins (AGP), with a protein moiety containing 10% of 4-hydroxyproline residues. They possess a β-(1→3)-Galp/β-(1→3,6)-Galp ratio of 0.80, with a sugars composition of Rha:Ara:Gal of 0.25:1.0:1.5, and containing 2mol% of glucuronic acid residues. Beyond the occurrence of single α-l-Araf residues and [α-l-Araf-(1→5)-α-l-Araf-(1→] disaccharide residues as side chains, these AGPs contain unusual side chains at O-3 position of the β-(1→6)-linked galactopyranosyl residues composed by [α-l-Rhap-(1→5)-α-l-Araf-(1→] and [α-l-Rhap-(1→5)-α-l-Araf-(1→5)-α-l-Araf-(1→] oligosaccharides. Rhamnoarabinosyl and rhamnoarabinoarabinosyl side chains are reported for the first time as structural features of plant arabinogalactan-proteins. [Copyright &y& Elsevier]

Abstract: The synthesis, structure elucidation, and antitumor activity of 11 xanthones are reported, being the compounds 3, 4, 6–8, and 9 described for the first time. Xanthones 1 and 2 were used as building blocks to obtain the prenylated derivatives 3–8. Prenylation was carried out using prenyl bromide in alkaline medium. Dihydropyranoxanthones 9–11 were obtained from compounds 4 and 5 by an oxidative ring closure. The structure of the compounds was established by IR, UV, MS, and NMR (1H, 13C, COSY, HSQC, and HMBC) techniques and for compounds 4, 6, and 11 the structure was confirmed by X-ray crystallographic analysis. The effect of the 11 xanthones on the in vitro growth of four human tumor cell lines, MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), SF-268 (central nervous system cancer), and UACC-62 (melanoma) is also described. [Copyright &y& Elsevier]

Abstract: 2-Styrylchromones are a small group of naturally occurring chromones, vinylogues of flavones (2-phenylchromones). Natural and synthetic 2-styrylchromones have been tested in different biological systems, showing activities with potential therapeutic applications. In particular, the potential and hitherto understudied antioxidant behavior of these compounds has been raised as a matter of interest. Thus the present work consisted in the study of the in vitro scavenging activities for reactive oxygen species (ROS) and reactive nitrogen species (RNS) of various 2-styrylchromone derivatives and structurally similar flavonoids. Some of the studied 2-styrylchromones proved to be extremely efficient scavengers of the different ROS and RNS, showing, in some cases, IC50s under 1μM. The hydroxylation pattern of 2-styrylchromones, especially in the B-ring but also in the A ring, modulates the activity of these compounds, the catecholic derivatives being the most effective scavengers. The styryl pattern also contributes to their observed outstanding antioxidant activity. In conclusion, the scavenging activities for ROS/RNS of 2-styrylchromone derivatives, here shown for the first time, provide novel and most promising compounds to be applied as antioxidants. [Copyright &y& Elsevier]

Abstract: The hydroformylation of Δ4- and Δ5-steroids, namely cholest-4-ene (1), 3β-acetoxycholest-4-ene (2), 3β-acetoxycholest-5-ene (3), and 3β-acetoxypregn-5-en-20-one (4), was studied using rhodium catalysts modified with P-donor ligands containing electron withdrawing substituents, such as tris(o-tert-butylphenyl)phosphite, tris(o-trifluoromethylphenyl)phosphine and tris(p-trifluoromethylphenyl)phosphine. The effect of temperature, pressure and ligand/Rh molar ratios on the regio- and stereoselectivity of the reaction were studied. Under the reaction conditions assayed, only the Δ4-steroids 1 and 2 are hydroformylated, producing the 4-formyl derivatives with 100 % regioselectivity and 70 and 60 % stereoselectivity for the β isomer, respectively. Δ5-Steroids 3 and 4 either did not react or produced traces of products from the isomerization of the double bond. Among the three catalysts used, only the Rh/tris(o-tert-butylphenyl)phosphite was able to catalyze the hydroformylation of Δ4-steroids. The two new formyl steroids obtained from 1, 4-formyl-5α-H-cholestane (6) and 4-formyl-5β-H-cholestane (7), were isolated as their acetal derivatives and fully characterized by 2D NMR techniques. The structure of the acetal arising from the minor aldehyde product of the reaction was further corroborated by X-ray analysis. The mechanism of the reaction for the conversion of 3β-acetoxycholest-4-ene 2 into 7 was investigated, through the hydroformylation of (1R)-(−)-myrtenyl acetate (5) as a cyclic allylic acetate model. The results show that the reaction does not take place through an allylic intermediate, but that the major aldehyde obtained from 2 undergoes AcOH elimination followed by stereoselective hydrogenation of the α,β-unsaturated aldehyde, leading to 7. [Copyright &y& Elsevier]

Abstract: A new pigment, resulting from the reaction between malvidin 3-glucoside and catechin in the presence of vanillin, was detected in a model solution. This newly formed anthocyanin-aryl-flavanol adduct was structurally characterized by 1D and 2D NMR and mass spectrometry, and its chromatic characteristics were studied by UV–Vis techniques. The new pigment was shown to have a wavelength of maximum absorption in the visible region (λ max) of 549nm, conferring on it a purple colour, and a molar extinction coefficient value (ε) of 12,247l·mol−1 ·cm−1. [Copyright &y& Elsevier]

Abstract: Azomethine ylides generated from the reaction of chromone-3-carbaldehyde with α-amino acids undergo 1,5-electrocyclization reactions to afford 3- and 4-(2-hydroxybenzoyl)pyrroles. These ylides can be trapped with dipolarophiles in 1,3-dipolar cycloaddition reactions to yield chromonyl pyrrolidines. The reaction of chromone-3-carbaldehyde with methyl glycinate gives a mixture of pyrrole, pyridine, and 3-aza-9-xanthenone derivatives. [Copyright &y& Elsevier]