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AbstractIn the present work, five pyrazole-hydrazone biomolecule ligands (L1–L5) were synthesized by condensation between 1H-pyrazole-3-carbohydrazide (2) and aromatic benzaldehydes. Their corresponding structures were elucidated employing NMR and FT-IR spectra and ESI-MS data. Li-Cu(II) complexes (i = 1–5) were evaluated for catecholase activity in situ at standard conditions. The findings disclose that the catecholase oxidation rate varies with the substituted functional groups in ligand and the anion type in the copper (II) salt. Catecholase activity results showed that the L(i = 1–5) -Cu(II)SO4 complexes exhibited efficient catalytic activity, and a maximum activity of 105 ± 42 µM.min−1 is obtained with L5-Cu(II)SO4. DFT and NBO calculations have been carried out to identify the global reactivity and the strength of interaction bonds between the donors and acceptors in L1–L5. The optimized structure of L1–L3 and L5 were found planar, while that of L4 is out of the molecular plan and forms a torsion angle of 18 degrees due to the presence of methoxy and hydroxyl group at meta and para. In L4, the 5-methyl-1H-pyrazole moiety. NBO findings show that the strongest interactions in L1–L5 are those involved in the electronic transition from π-bonding → π*-antibonding and LP → π*- antibonding molecular orbitals. Further, the anti-SARS-CoV-2 of L1–L5 are investigated by estimating their binding affinities into its binding. The docking results reveal that L1–L5 may act as SARS-CoV-2 main protease inhibitors with estimated binding energies in the −6.00 to −8.0 kcal.mol−1 range. [ABSTRACT FROM AUTHOR]

The bromination of eugenol using molecular bromine (Br2 ) has been widely reported. However, the outcomes have been inconsistent, and as a result, the specific steps of the bromination process have not been definitively established. This research aims to synthesize various derivatives of bromo eugenol, incorporating bromine atoms either in the alkene group, the aromatic ring, or both. The synthetic approaches employed include (1) direct bromination of eugenol using 1.2, 2.4, and 3.6 equivalents (equiv) of Br2 in chloroform, (2) bromination of eugenyl benzoate with 2.4 equiv of Br2 in chloroform, and (3) debromination of the 1,2-dibromide functionality in selected bromination products using an excess of zinc in ethanol. The bromination steps of eugenol were then proposed based on the composition of the products obtained. Alkene bromination of eugenol predominated with 1.2 equiv of Br2, followed by aromatic bromination with excess Br2 (2.4 and 3.6 equiv). Aromatic substitution primarily occurred at position 6 (ortho to the hydroxyl group) and subsequently at position 5 (para to the methoxy group). Based on these results, we propose that the bromination of eugenol with Br2 proceeds initially through electrophilic addition to the alkene group, followed by electrophilic substitution on the aromatic ring. Protection of the phenol as a benzoyl ester shifted the regioselectivity of the first aromatic bromination from position 6 to 5. Furthermore, the 1,2-dibromide group has been successfully removed by zinc, resulting in derivatives containing bromine atoms only at the aromatic ring. This is by far the first comprehensive report on the bromination of eugenol with Br2 and the first one reporting the bromination of alkene as the main route of bromination with a nearly equimolar amount of Br2 . [ABSTRACT FROM AUTHOR]

Transforming renewable lignin into high value‐added chemicals is a forward‐looking strategy to address the resource waste caused by insufficient utilization of biomass resources. On this basis, studying the efficient conversion of lignin to aldehydes/acids and their reaction mechanisms has become an attractive topic. A systematic investigation of the gas‐phase oxidation reaction mechanisms of the three model compounds initiated by O2 was carried out at the atomic and molecular levels by using density functional theory (DFT). Further revealing of oxidation behavior on two reaction sites of phenolic hydroxyl group and hydroxymethyl group were accomplished in detail. The potential energy surface information of 21 possible reaction channels of two pathways were obtained at B3LYP/6‐311+G(d,p) level. The influence of substituent effects on the reaction energy barrier was estimated. The calculation results showed that the reactivity of phenolic hydroxyl group is stronger than that of hydroxymethyl group, because the reaction Gibbs potential barriers are lower by about 4.9–8.7 kcal/mol. The reaction energy barriers on phenolic hydroxyl group site and hydroxymethyl group site decrease with the increase of the number of methoxy groups. Revealing the oxidation processes of lignin model compounds will provide a deeper understanding on the reaction mechanism and provide theoretical support for further experimental research on the conversion of lignin into high value‐added chemicals. [ABSTRACT FROM AUTHOR]

This article aimed to separate and identify molecular species obtained in the sol-gel process by gas chromatography coupled with mass spectrometry (GC-MS), for the reaction mixture with methyltrimethoxysilane (MTMOS). In the presence of an unhydrolyzed methyl group, the molecular species starting with the cyclic trimers, a series of geometric isomers were separated and identified due to the position of the methyl groups in relation to the ring plane of each siloxane molecule; in addition, for the hydrolyzed products, isomers with different relative positions of the hydroxyl groups to the methyl and methoxy groups were separated and identified. The reactivity of the new molecular species formed determines subsequent stages of the sol-gel process. [ABSTRACT FROM AUTHOR]

The process of curing the acrylic oligomers for rapid thermal curing coatings in the presence of hexa(methoxymethyl)melamine (HMMM), tetra(butoxymethyl)glycoluril (TBMG), and tetra(methoxymethyl)glycoluril (TMMG) has been studied. When HMMM is used as a hardener, the content of hydroxyl groups in the terpolymer and also the crosslinking agent concentration have little effect on the initial cure rate. It has been established that during the curing of the TMMG composition, the amount of the network polymer and the initial curing rate decrease at short curing times only. It has also been revealed that the use of butoxy groups instead of methoxy groups as blocking agents leads both to a decrease in the initial cure rate and the gel fraction limiting value from 98 to 80%. When it comes to TBMG-containing compositions, a decrease in the part of hydroxyl groups in the copolymer leads to a significant fall in the initial curing rate and also in the gel fraction content. Regardless of the crosslinking agent used, an acceleration of the curing process is observed with an increase in the catalyst content in the compositions. [ABSTRACT FROM AUTHOR]

Botrytis cinerea is a phytopathogenic fungus that causes serious damage to the agricultural industry by infecting various important crops. 2-allylphenol has been used in China as a fungicide for more than a decade, and it has been shown that is a respiration inhibitor. A series of derivatives of 2-allylphenol were synthesized and their activity against B. cinerea was evaluated by measuring mycelial growth inhibition. Results indicate that small changes in the chemical structure or the addition of substituent groups in the aromatic ring induce important variations in activity. For example, changing the hydroxyl group by methoxy or acetyl groups produces dramatic increases in mycelial growth inhibition, i.e., the IC50 value of 2-allylphenol decreases from 68 to 2 and 1 μg mL−1. In addition, it was found that the most active derivatives induce the inhibition of Bcaox expression in the early stages of B. cinerea conidia germination. This gene is associated with the activation of the alternative oxidase enzyme (AOX), which allows fungus respiration to continue in the presence of respiratory inhibitors. Thus, it seems that 2-allylphenol derivatives can inhibit the normal and alternative respiratory pathway of B. cinerea. Therefore, we believe that these compounds are a very attractive platform for the development of antifungal agents against B. cinerea. [ABSTRACT FROM AUTHOR]

Harmaline (1) and harmalol (2) represent two 3,4-dihydro-β-carboline (DHβCs) most frequently reported in a vast number of living systems. Fundamental aspects including the photosensitizing properties, cellular uptake, as well as the cyto- and phototoxicity of 1 and 2 were investigated herein. The molecular basis underlying the investigated processes are elucidated. Data reveal that both alkaloids show a distinctive pattern of extracellular DNA photodamage. Compound 1 induces a DNA photodamage profile dominated by oxidised purines and sites of base loss (AP sites), whereas 2 mostly induces single-strand breaks (SSBs) in addition to a small extent of purine oxidative damage. In both cases, DNA oxidative damage would occur through type I mechanism. In addition, a concerted hydrolytic attack is suggested as an extra mechanism accounting for the SSBs formation photoinduced by 2. Subcellular internalisation, cyto- and phototoxicity of 1 and 2 and the corresponding full-aromatic derivatives harmine (3) and harmol (4) also showed quite distinctive patterns in a structure-dependent manner. These results are discussed in the framework of the potential biological, biomedical and/or pharmacological roles reported for these alkaloids. The subtle structural difference (i.e., the exchange of a methoxy group for a hydroxyl substituent at C(7)) between harmaline and harmalol, gives rise to distinctive photosensitizing and subcellular localisation patterns. [ABSTRACT FROM AUTHOR]

The aromatic biopolymer lignin, present in lignocellulosic material, can act as an antioxidant and has antimicrobial and UV blocking properties due to the presence of aromatic ring and phenolic hydroxyl groups with aliphatic hydroxyl, carboxyl, methoxy groups. It is produced in huge amounts as a by-product during the delignification process in the paper and pulp industries. Lignin-based polymer composites with advantageous properties can fulfill the growing demand for lightweight polymer composites. Incorporating lignin as reinforcement in polymer composite can make it more environmentally friendly. Among four technical lignin, kraft lignin and lignosulfonate have a unique molecular structure that includes sulfur and can be extracted from black liquor and spent liquor, respectively. Moreover, the negatively charged sulfite groups in lignosulfonate can have an electrostatic attraction to a wide range of positively charged polymers and materials, making it an ideal additive for the adsorbent material. The main intention of this review is to increase the knowledge on the use of cheap and widely available kraft lignin and lignosulfonate as reinforcement in polymer composites and to find the shortcomings to advance further research on the application of technical lignin. The article mainly focuses on advancements in kraft lignin and lignosulfonate polymer composites. [ABSTRACT FROM AUTHOR]

Four A2B cobalt corrole complexes 1–4 appending two methoxy or hydroxyl groups on the 10‐meso phenyl group had been synthesized. Four cobalt corroles showed high electrocatalytic activity for hydrogen evolution reaction (HER) in the organic phase and in the aqueous phase. The hydrogen evolution pathway was EECEC when using acetic acid as proton source. When trifluoroacetic acid was used as proton source, the hydrogen evolution route via EECEC or EECC depending on the concentration of trifluoroacetic acid. Cobalt corrole 4 showed the best HER performance with the kobs of 122.68 s−1 in organic phase and the TOF of 832.2 h−1 in aqueous phase respectively. The results suggested the phenyl hydroxyl group at the cobalt corrole peripheral may act as the proton relay group in HER and the o‐hydroxyl of phenyl was better than m‐ hydroxyl for proton relay. [ABSTRACT FROM AUTHOR]

Polymethoxyflavonoids (PMFs) are a large group of compounds belonging to the more general class of flavonoids that possess a flavan carbon framework decorated with a variable number of methoxy groups. Hydroxylated polymethoxyflavonoids (HPMFs), instead, are characterized by the presence of both hydroxyl and methoxy groups in their structural unities. Some of these compounds are the aglycone part in a glycoside structure in which the glycosidic linkage can involve the −OH at various positions. These compounds are particular to Citrus genus plants, especially in fruits, and they are present mainly in the peel. A considerable number of PMFs and HPMFs have shown promising biological activities and they are considered to be important nutraceuticals, responsible for some of the known beneficial effects on health associated with a regular consumption of Citrus fruits. Among their several actions on human health, it is notable that the relevant contribution in controlling the intracellular redox imbalance is associated with the inflammation processes. In this work, we aim to describe the status concerning the chemical identification and the anti-inflammatory activity of both PMFs and HPMFs. In particular, all of the chemical entities unambiguously identified by isolation and complete NMR analysis, and for which a biochemical evaluation on the pure compound was performed, are included in this paper. [ABSTRACT FROM AUTHOR]

Biflavonoids, particularly 3′-8′′-biflavones, have emerged as promising candidates for drug discovery due to their diverse biological activities. In this study, we investigated the comparative effects of 3′-8′′- biflavones (amentoflavone, bilobetin, ginkgetin, isoginkgetin, and sciadopitysin) and their monomeric subunits (apigenin, genkwanin, acacetin) on various parameters. We assessed their radical scavenging activity, antifungal potential against mycotoxigenic fungi, and inhibitory effects on key enzymes. While all compounds exhibited weak radical scavenging activity, their antifungal efficacy varied depending on concentration and fungal species. Notably, ginkgetin and isoginkgetin demonstrated potent acetylcholinesterase inhibition, whereas monomeric flavonoids displayed stronger tyrosinase inhibition. Amentoflavone exhibited notable inhibitory effects on α-amylase and α-glucosidase, with 3′-8′′- biflavones generally showing enhanced enzyme inhibitory activity compared to monomeric subunits. Overall, our findings suggest that 3′-8′′-dimerization enhances certain enzyme activities, albeit influenced by the compound's structural features such as the presence of hydroxyl and methoxy groups. [ABSTRACT FROM AUTHOR]

Lignin is a green and sustainable feedstock for the production of chemicals and materials; however, its utilization is still low. Over the past decade, remarkable progress has been achieved in the extraction, degradation, and functionalization of lignin and the fabrication of lignin-containing materials. In this review, we provide a critical examination of the in-depth insights into recently developed strategies for the green and efficient extraction, selective degradation and diverse functionalization of lignin. Its green extraction involves the judicious selection of solvent, and mild enzymatic conditions, leading to different technical lignin products. The degradation of lignin can be achieved via thermochemical, electrochemical, photocatalytic and biological processes. Lignin can be functionalized via the modification of its aromatic rings, modification of its hydroxyl groups, modification of its methoxy groups, and graft copolymerization. Based on the top-down degradation and bottom-up functionalization strategies, lignin can be converted into a variety of value-added chemicals and polymers and can be engineered into many types of lignin-based materials. These materials hold great promise in energy storage, targeted drug delivery, efficient adsorption and catalysis, functional packaging and slow-release fertilizers. The correlation among the sources, degradation, and functionalization of lignin and lignin-based materials is discussed. Also, we present a techno-economic analysis on the production of chemicals and materials from lignin. Finally, an outlook for lignin valorization is presented. [ABSTRACT FROM AUTHOR]

Covalent attachment of methoxy poly(ethylene) glycol (mPEG) to therapeutic molecules is widely employed to improve their systemic circulation time and therapeutic efficacy. mPEG, however, can induce anti-PEG antibodies that negatively impact drug therapeutic effects. However, the underlying mechanism for specific binding of antibodies to mPEG remains unclear. Here, we determined the first co-crystal structure of the humanized 15-2b anti-mPEG antibody in complex with mPEG, which possesses a deep pocket in the antigen-binding site to accommodate the mPEG polymer. Structural and mutational analyses revealed that mPEG binds to h15-2b via Van der Waals and hydrogen bond interactions, whereas the methoxy group of mPEG is stabilized in a hydrophobic environment between the VH:VL interface. Replacement of the heavy chain hydrophobic V37 residue with a neutral polar serine or threonine residue offers additional hydrogen bond interactions with methoxyl and hydroxyl groups, resulting in cross-reactivity to mPEG and OH-PEG. Our findings provide insights into understanding mPEG-binding specificity and antigenicity of anti-mPEG antibodies. Methoxy polyethylene glycol (mPEG) is widely attached to drug molecules to improve their therapeutic efficacy, however mPEG can induce anti-PEG antibodies that negatively impact their therapeutic effects. Here, the authors determine the co-crystal structure of the humanized 15-2b anti-mPEG antibody with mPEG, providing insights into understanding mPEG-binding specificity and antigenicity of anti-mPEG antibodies. [ABSTRACT FROM AUTHOR]

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Red mud (RM) is a solid waste of Bayer's alumina industry production process, which comprises a mixture of diverse minerals. After calcination, the minerals in RM are present in the form of oxides, exhibiting remarkable catalytic performance for biomass pyrolysis. It is thought that pyrolysis of lignin generates renewable aromatic chemicals. In this paper, the effect of in-situ catalysis of calcinated RM on the distribution of lignin pyrolysis volatile products is investigated. In addition, upgrading of tar by components in RM, including SiO 2 , Al 2 O 3 , Fe 2 O 3 , and Na 2 O is also discussed. The results show that the addition of RM in lignin pyrolysis leads to lower char yield and higher gas yield. RM catalyzes the breaking and rearrangement of methoxy groups and induces the generation of hydroxyl groups, which leads to an increase from 1.96 to 3.96 wt% in monophenol content of the tar. Furthermore, the activation of C-O bonds by Fe 2 O 3 and the redox properties of Fe 2 O 3 (FeSi) combine to stimulate the production of monophenols and aldehydes by 30.8 % and 148.2 %, while Al 2 O 3 (AlSi) boosts the production of guaiacols by 32.0 % comparing with SiO 2 (Si). It is found that synergistic effect between multiple species improves the catalytic performance, the yield of tar reaches 24.5 wt% and the selectivity of oxygenated compounds achieves 94.4 % (FeAlSiNa). The catalytic performances of RM for product yield and tar component distribution are similar to that of FeSi, indicating that Fe 2 O 3 and SiO 2 play a main catalytic role in RM. [Display omitted] • Oxygen-containing compounds are converted into phenols with the addition of RM. • Fe 2 O 3 in RM boosts the production of monophenols and aldehydes by 30.8 % and 148.2 %. • Al 2 O 3 stimulates the production of guaiacols by 32.0 %. [ABSTRACT FROM AUTHOR]

Ovalbumin (OVA) is a common carrier with high efficiency to deliver flavonoids. The aim of this study was to investigate the interaction mechanism of OVA and four flavonoids (quercetin (Que), myricetin (Myri), isorhamnetin (Ish), and kaempferol (Kaem)) with similar structures by fluorescence spectra, SDS−PAGE, FT−IR, and molecular docking analysis, and the effect on the antioxidant abilities of flavonoids was also evaluated. Results indicated that the antioxidant activity of flavonoids was positively correlated to the number of phenolic hydroxyl groups of on the B-ring, and weakened when the C-3′ position was replaced by a methoxy group. The addition of OVA enhanced the antioxidant activity of Que/Kaem, while it masked the antioxidant activity of Myri. The formation of Que/Myri/Ish/Kaem−OVA complexes was a spontaneous exothermic process driven mainly by hydrogen bond and van der Waals force, which could result in the change in OVA conformation and induce the transformation of α-helix to β-sheet. Among these, Kaem exhibited the strongest binding ability with OVA, and showed the greatest impact on the secondary and conformational structure of OVA, followed by Que. The hydroxylation of C-3′ and methoxylation of C-5′ weaken the interaction of Kaem with OVA. Molecular docking analysis suggested that Que, Myri, Ish, and Kaem formed six, three, five, and four hydrogen bonds with OVA, and the number of hydrogen bonds was not positively correlated with their binding constants. Our findings can provide a theoretical basis for the application of OVA on improving the antioxidant activity of flavonoids, and may help to explain the delivery efficiency of OVA on different bioactive constituents. [ABSTRACT FROM AUTHOR]

Industrial lignin is oxidized by H2O2 and (NH4)2S2O8 under mild conditions and used in lignin-phenolic resin adhesives. After H2O2 treatment, the molecular weight of lignin is reduced by 9.8%,the content of phenolic hydroxyl group is increased by 27.46%,and the reactivity is improved; after treatment with (NH4)2S2O8,the content of lignin methoxy group is reduced by 9.92%,and the phenolic hydroxyl group is increased by 12.15%.Reactivity with formaldehyde increase. Under the same substitution rate, the free phenol and free formaldehyde content of the adhesive prepared by H2O2, (NH4)2S2O8 treatment of lignin decreased, and the bonding strength increased. Among them, (NH4)2S2O8treatment of lignin to prepare adhesives has a significant increase in bonding strength. Under 140 ℃ and 1.20 MPa hot pressing conditions, the bonding strength of L3PF-50% reached 1.80 MPa, an increase of 35.34%.Under 160 ℃ and 1.60 MPa hot pressing conditions, the bonding strength of L3PF-50% reached 1.94 MPa, an increase of 33.79%,and the strength of L3PF-80% increased by 29.63% to 1.40 MPa. [ABSTRACT FROM AUTHOR]

[Display omitted] • The selected polyphenols formed VI-type inclusion complexes with starch. • The presence of hydrophobic groups promoted the complexation. • The bulky framework of polyphenols caused loosely structured inclusion complexes. • The ortho-hydroxyl group favored the compact structural inclusion complexes. • The structure of inclusion complexes could modulate the stability of polyphenols. Polyphenols are known to undergo thermal degradation and their bioactivity is reduced. In this study, the thermal degradation of polyphenols was modulated by the complexation between polyphenols and high amylose corn starch (HACS). The inclusion complex between ferulic acid with hydrophobic group methoxy and HACS had the highest encapsulation efficiency (EE = 26.15 %), loading efficiency (LE = 2.38 %) and thermal stability (DPPH radical scavenging activity was reduced by only 5.99 % after baking). After complexing with HACS, protocatechuic acid with ortho-position hydroxyl group had a higher encapsulation rate and thermal stability than 3, 5-dihydroxybenzoic acid with meta-position hydroxyl. In addition, soy isoflavone with the higher logarithmic value of octanol-water partition coefficient (Log P = 3.66) resulted in higher encapsulation rate and thermal stability than naringenin (Log P = 2.11). The results suggest that the complexation between polyphenols and starch protects the bioactivity of polyphenols and improves the processing suitability of polyphenols. [ABSTRACT FROM AUTHOR]

The samples of alumina of different origin exhibit different activity in the reaction of methanol dehydration to dimethyl ether (DME). To elucidate reasons for differences in their activity, a comparative study of the structural (XRD analysis, specific surface area, and porosity) and surface (Brønsted and Lewis acidity and hydroxyl coverage) properties of alumina samples was carried out. The presence of formates, aldehyde complexes, and bridging and terminal methoxy groups in different ratios on the surface of aluminum oxide samples under the reaction conditions of methanol conversion was detected using in situ IR spectroscopy. The reactivity of the detected surface compounds was compared for all of the samples. It was found that the activity of the samples in the formation of DME correlated with the rate of conversion of bridging methoxy groups. In turn, the rate of conversion of the bridging methoxy groups was determined by the acidity of bridging hydroxyl groups. An increase in acidity led to an increase in the bond strength of the methoxy group with the surface and a decrease in the rate of its conversion into DME. Linear methoxy groups underwent oxidative conversion into formate and aldehyde surface complexes. The nature of the oxidizing ability of an alumina surface is discussed. [ABSTRACT FROM AUTHOR]

We report an electrochemical approach to extract methanol from lignin with a maximum efficiency of 95% under mild conditions of ambient pressure and a temperature of 75 °C. Hydroxyl radicals were generated from water over a platinum-sputtered anode and attacked the syringyl and guaiacyl units of the lignin. Methoxy groups in the units were demethylated to methanol with a yield greater than 40% through the formation of hemiketal intermediates. The electro-oxidation was coupled to cathode reactions that generated hydrogen in a helium flow and electric power in an air flow. Another important aspect of this approach is that no extra energy or effort was required to separate methanol from the reaction system. This technology can accelerate the replacement of fossil organic resources with renewable biomass resources. [Display omitted] • Lignin is anodically demethylated to methanol under mild conditions. • The faradaic efficiency for methanol formation reaches 95%. • Methanol yields of over 40% are obtained irrespective of the lignin weight. • Hydroxyl radicals function as a reaction initiator for demethylation. • The anode reaction proceeds in both electrolysis and fuel-cell modes. [ABSTRACT FROM AUTHOR]

Pre-regulating the molecular composition and structural characteristics of lignin before pyrolysis is of great significance for the lignin valorization. In this work, torrefaction pretreatment of softwood kraft lignin (SKL) is carried out at different temperatures, and the characterization results show that torrefaction pretreatment is beneficial for removing oxygen element from SKL, which increases the high heating value of torrefied lignins (TLs). In addition, torrefaction pretreatment has a destructive effect on C β -O-C 4 linkages, and reduces the molecular weight of TLs. Torrefaction pretreatment also removes the thermally unstable components from SKL and increases the release rate of pyrolysis volatiles. Furthermore, torrefaction pretreatment degrades the methoxy group (-OCH 3) in SKL into phenolic hydroxyl group, which reduces the yield of guaiacyl type phenols in TLs pyrolysis products, and significantly increases the yield of catechol type phenols from 23.59% in SKL to 47.50% in TL300. • Torrefaction pretreatment is beneficial to the removal of O and the increase of HHV of lignin. • Torrefaction pretreatment reduces the C β -O-C 4 linkage and molecular weight of lignin. • Torrefaction pretreatment increase the content of C-phenols from lignin pyrolysis. • Torrefaction pretreatment is conducive to the increment of MAHs. [ABSTRACT FROM AUTHOR]

Directional cleavage the linkages bonds between the lignin units is of great scientific interest although technically challenging. In this work, free radical depolymerization of lignin was investigated by using three model compounds. Peroxymonosulfate (PMS) was activated by N-doped carbon and thermal method, and could generate reactive oxygen species (ROS), including hydroxyl radical (OH ∙), sulfate radical anion (S O 4 ∙ − ), superoxide anion (O 2 ∙ − ) and singlet oxygen( O 1 2). pH of solution was used to regulate the types of ROS. The results showed that 1) pH value can tune the reaction pathway by regulating the type of ROS; 2) There should be an optimal temperature for maximum selectivity of monomer products in the depolymerization proces of lignin model compounds by ROS; 3) Hydroxyl group and Methoxy group can activate the reactivity of lignin model compounds, which is conductive to the directional generation of monomer products. In addition, the depolymerization mechanism of lignin model compound by PMS was proposed. This work illustrated the reaction characters and the influence factors of the lignin depolymerization by PMS, the results would facilitate the optimization of the lignin valorization process. [Display omitted] • The lignin depolymerization process oxidized by PMS was investigated. • The reaction pathway of lignin model compound depolymerization by PMS was proposed. • The controll step of depolymerization proces of α-O- Ar lignin model compounds was illustrated. • pH value can regular the reaction pathway of depolymerize lignin model compounds by ROS. [ABSTRACT FROM AUTHOR]

The syntheses of oxidorhenium(v) complexes [ReOCl(L1a–c)2] (3a–c), equipped with the bidentate, mono-anionic phenol–dimethyloxazoline ligands HL1a–c are described. Ligands HL1b–c contain functional groups on the phenol ring, compared to parent ligand 2-(4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl)-phenol H1a; namely a methoxy group ortho to the hydroxyl position (2-(4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl)-6-methoxyphenol, H1b), or a nitro group para to the hydroxyl position (2-(4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl)-4-nitrophenol, H1c). Furthermore, oxidorhenate(v) complexes (NBu4)[ReOCl3(L1a–b)] (2a–b) were synthesized for solid state structural comparisons to 3a–b. All novel complexes are fully characterized including NMR, IR and UV-Vis spectroscopy, MS spectrometry, X-ray crystallography, elemental analysis as well as cyclic voltammetry. The influence of functional groups (R = –H, –OMe and –NO2) on the catalytic activity of 3a–c was investigated in two benchmark catalytic reactions, namely cyclooctene epoxidation and perchlorate reduction. In addition, the previously described oxidorhenium(v) complex [ReOCl(oz)2] (4), employing the phenol–oxazoline ligand 2-(4,5-dihydro-2-oxazolyl)phenol Hoz, was included in these catalysis studies. Complex 4 is a rare case in oxidorhenium(v) chemistry where two stereoisomers could be separated and fully characterized. With respect to the position of the oxazoline nitrogen atoms on the rhenium atom, these two stereoisomers are referred to as N,N-cis and N,N-trans isomer. A potential correlation between spectroscopic and structural data to catalytic activity was evaluated. [ABSTRACT FROM AUTHOR]

Introduction. The aim of this review is to focus on the unique chemistry of curcumin to explain its dissimilar behaviour in different mediums. Materials and methods. The papers regarding structure-activity relationship studies of curcumin as antioxidant or pro-oxidant were examined. This review summarizes the achievements made in this field since 1980 Results and discussion. Curcumin is the principal curcuminoid found in turmeric and is generally considered as the most active constituent of turmeric compared to other curcuminoids. Enormous research has been carried out to explain the beneficial activities of curcumin. It has been the centre of attraction for potential treatment of an array of diseases such as cancer, Alzheimer, diabetes, allergies, arthritis and other chronic illnesses. It also possesses antioxidant activity at lower concentration. In contrast, the pro-oxidant effect has also been reported. The behaviour of curcumin to act as antioxidant or pro-oxidant depends on its structural form. Curcumin exists in two tautomeric forms, keto and enol. In keto form, curcumin exerts antioxidant activity. The enol form is prone to degradation. Hence, it is essential to maintain curcumin in keto form. In polar and acidic medium, curcumin exists in keto form whereas in non-polar and basic medium, it undergoes degradation. The mechanisms of degradation of curcumin under different mediums are discussed. Under basic conditions, nucleophilic attack of hydroxyl group is involved and under non-polar conditions, free radical mechanism is involved. Degradation under basic conditions leads to complete breaking of the molecule while under non-polar conditions, it proceeds via peroxide intermediate formation, clarifying the pro-oxidant effect of curcumin. In either of the cases, vanillin is the degradation product besides other degradation products. The discussion is further extended for the other two curcuminoids, viz. demethoxycurcumin and bisdemethoxycurcumin as well. The antioxidant activity of curcumin is the highest whereas bisdemethoxycurcumin exhibits least antioxidant activity amongst curcuminoids. However, the rate of degradation of curcumin is also maximum amongst curcuminoids followed by demethoxycurcumin and bisdemethoxycurcumin. This reveals that the electron donating methoxy group influences the activity of curcuminoids. Thus, structure of a constituent is responsible for its activity. Conclusion. The importance of a particular medium to achieve the beneficial activities of curcumin is confirmed. [ABSTRACT FROM AUTHOR]

Introduction. Curcumin, demethoxycurcumin and bisdemethoxycurcumin collectively constitute curcuminoids, exhibit different rates of degradation as well as therapeutic properties. Their remarkable dissimilar behaviour is affiliated to their tendency to undergo keto-enol tautomerism whereas their rates of degrading and imparting therapeutic properties depend on the ratio of keto and enol tautomers of individual curcuminoid. Materials and Methods. The aim of the current review is to focus on the ratio of keto and enol tautomers and to explain how the ratio of the two tautomers affects the rate of activities of the curcuminoids. The papers regarding variations in the rate of activities of curcuminoids were scrutinized. The factors affecting the ratio of keto-enol tautomerism were studied. Results and discussion. Structurally, curcuminoids are the compounds possessing β-diketone moiety. The characteristic property of compounds containing β-diketone moiety is to exhibit keto-enol tautomerism. Hence, each curcuminoid is a mixture of keto and enol tautomers. The keto tautomer of curcumioids is responsible for their therapeutic activities. On the other hand, enol tautomer of curcuminods has tendency to undergo degradation. Hence, the ratio of keto and enol tautomer needs to be considered while studying the activities of curcuminoids. Nevertheless, the ratio of keto and enol tautomer depends on the existence of other functional groups. Because of the presence of electron donating hydroxyl group, the proportion of enol tautomer predominates in curcuminoids. Further, due to the presence of two more electron donating methoxy groups in curcumin, the ratio of the enol tautomer is higher and hence, the susceptibility to undergo degradation is greater than demethoxycurcumin, which contains only one methoxy group. The ratio of the enol tautomer is minimum in bisdemethoxycurcumin amongst all the curcuminoids, which is devoid of methoxy group. Consequently, bisdemethoxycurcumin has the least rate of degradation amongst curcuminoids. Methoxy group enhances the activity of the functional sites in curcuminoids in keto form. Therefore, curcumin shows maximum beneficial activities in keto form amongst all the curcuminoids, followed by demethoxycurcumin and bisdemthoxycurcumin. Thus, the rate of the activities displayed by curcuminoids is governed by their keto and enol proportion. Conclusion. It can be concluded from this review article that besides β-diketone moiety, responsible for keto-enol tautomerism, other groups also play an important role in determining the ratio of keto and enol tautomers. [ABSTRACT FROM AUTHOR]

1,4-Naphthoquinones exhibit strong activity as antimalarial, antibacterial, antifungal and anticancer agents. These kinds of compounds have also shown phytotoxic activity. The first example of an allelochemical to be described was naphthoquinone juglone (5-hydroxy-1,4-naphthoquinone). This fact led us to conduct a study of the phytotoxic activity and structure-activity relationships of 26 naphthazarin derivatives. The compounds belong to two main groups, 5,8-dioxygenated-1,4-naphthoquinones and 1,4,5,8-tetraoxygenated naphthalenes with different functionalizations and chains at positions 2, 4, 6 and 7. The results show that substitution with halogens and modification of the hydroxyl groups on the aromatic ring with methoxy or acetate groups seems to play an important role in enhancing the activity. [ABSTRACT FROM AUTHOR]

Curcumin (diferuoyl methane) is a yellow active ingredient present in turmeric. It is a homodimer of feruloylmethane that comprises a hydroxyl and methoxy group (heptadiene with two Michael acceptors), and α-, β-diketone. It contains various metabolites, i.e. hexahydrocurcumin (HHC), tetrahydrocurcumin (THC), octahydrocurcumin (OHC), dihydrocurcumin (DHC), curcumin sulphate, and curcumin glucuronide. Curcumin has been proven the most effective histone deacetylase (HDAC) inhibitor in HeLa nuclear extracts. It has the ability to affect the Akt, growth factors, NF-κB, and metastatic and angiogenic pathways. Curcumin has a strong therapeutic or preventive potential against several major human ailments, i.e. suppression of inflammation, cardiovascular, diabetes, tumorigenesis, chronic fatigue, antidepressant and neurological activities, depression, loss of muscle and bone, and neuropathic pain. In future, higher utilisation of curcumin as an active agent in food based products is required to curtail the human health disorders. [ABSTRACT FROM AUTHOR]

Five bpa (bis(2-picolyl)amine) derivatives ( 1b , 2e , 3f , 4c , 5d ) carrying ether tethers with hydroxyl and methoxy groups, have been synthesized from pyridine aldehyde and the respective amines by reductive amination. Their Cu(II) complexes carrying additional nitrato ( 6a – b ) and perchlorato ( 7a – e ) ligands, respectively, have been characterized and subjected to DNA cleavage studies. Since the hydrolytic DNA cleavage activity of 6a is known from the literature, further experiments comprising the novel derivatives have been carried out. These reveal that derivative 7e was able to generate 10 times more linear DNA in a standard cleavage experiment than 6a . Considering the redox activity of the Cu(II) center, a possible oxidative cleavage activity of this kind of bpa complexes was also investigated. [ABSTRACT FROM AUTHOR]

Naturally occurring homoisoflavonoids containing either 5,7-dihydroxy-6-methoxy or 7-hydroxy-5,6-dimethoxy groups such as the antiangiogenic homoisoflavanone, cremastranone, were synthesized via three or four linear steps from the known 4-chromenone. This facile synthesis includes chemoselective 1,4-reduction of 4-chromenone and selective deprotection of 3-benzylidene-4-chromanone a containing C7-benzyloxy group. [ABSTRACT FROM AUTHOR]

Anti-DPPH radical effect as well as anti-peroxide activity of o -hydroxyl, o -methoxy, and alkyl ester derivatives of p -hydroxybenzoic acid in a bulk fish oil system and its O/W emulsion were investigated. Electronic phenomena, intra- and/or intermolecular hydrogen bonds, interfacial properties, and chemical reaction of the solvent molecules with phenolic compounds were considered to be mainly involved in the antiradical activities observed. Antioxidant activity of the phenolic acids derivatives as a function of these factors was variously affected by the environmental conditions which may occur in practice. [ABSTRACT FROM AUTHOR]

C20H22N2O6, monoclinic, P21/c (no. 14), a = 8.6657(6) Å, b = 18.6201(14) Å, V = 3605.9(5) ų, c = 22.3583(18) Å, Z = 8, Rgt(F) = 0.067, β = 91.808(3)°, wRref(F²) = 0.177, T = 100(2) K. [ABSTRACT FROM AUTHOR]

C20H22N2O6, monoclinic, P21/c (no. 14), a = 8.6657(6) Å, b = 18.6201(14) Å, V = 3605.9(5) ų, c = 22.3583(18) Å, Z = 8, Rgt(F) = 0.067, β = 91.808(3)°, wRref(F²) = 0.177, T = 100(2) K. [ABSTRACT FROM AUTHOR]

Thekinetics and mechanism of the CH3+ O reaction andrelated isomerization–decomposition of CH3O andCH2OH radicals have been studied by ab initio molecularorbital theory based on the CCSD(T)/aug-cc-pVTZ//CCSD/aug-cc-pVTZ,CCSD/aug-cc-pVDZ, and G2M//B3LYP/6-311+G(3df,2p) levels of theory.The predicted potential energy surface of the CH3+ O reactionshows that the CHO + H2products can be directly generatedfrom CH3O by the TS3 → LM1 → TS7 →LM2 → TS4 path, in which both LM1 and LM2 are very loose andTS7 is roaming-like. The result for the CH2O + H reactionshows that there are three low-energy barrier processes includingCH2O + H → CHO + H2via H-abstractionand CH2O + H → CH2OH and CH2O + H → CH3O by addition reactions. The predictedenthalpies of formation of the CH2OH and CH3O radicals at 0 K are in good agreement with available experimentaldata. Furthermore, the rate constants for the forward and some keyreverse reactions have been predicted at 200–3000 K under variouspressures. Based on the new reaction pathway for CH3+O, the rate constants for the CH2O + H and CHO + H2reactions were predicted with the microcanonical variationaltransition-state/Rice–Ramsperger–Kassel–Marcus(VTST/RRKM) theory. The predicted total and individual product branchingratios (i.e., CO versus CH2O) are in good agreement withexperimental data. The rate constant for the hydrogen abstractionreaction of CH2O + H has been calculated by the canonicalvariational transition-state theory with quantum tunneling and small-curvaturecorrections to be k(CH2O + H →CHO + H2) = 2.28 × 10–19T2.65exp(−766.5/T) cm3molecule–1s–1for the 200–3000 K temperaturerange. The rate constants for the addition giving CH3Oand CH2OH and the decomposition of the two radicals havebeen calculated by the microcanonical RRKM theory with the time-dependentmaster equation solution of the multiple quantum well system in the200–3000 K temperature range at 1 Torr to 100 atm. The predictedrate constants are in good agreement with most of the available data. [ABSTRACT FROM AUTHOR]

[Display omitted] • A NiMo-doped catalyst with optimal Ni/Mo ratio and carrier led to hydrocarbon bio-oil with low selectivity of polyaromatics and methane. • Two coefficients were proposed to qualitatively evaluate the activity of NiMo catalysts. • The effect of hydrogen pressure on catalytic activity of NiMo-doped catalysts was illustrated. • The synergistic mechanism of Ni and Mo was studied during the catalytic hydropyrolysis of lignin. • The evolution mechanism of lignin hydropyrolysis volatiles over NiMo/ZrO 2 was proposed. NiMo-doped catalysts were investigated for the conversion of lignin to drop-in fuel through catalytic hydropyrolysis. The influence of NiMo-doped catalysts with different carriers and Ni/Mo molar ratios on the hydropyrolysis product distribution were studied using both lignin and lignin model compounds. Two coefficients were proposed to qualitatively evaluate the catalytic performance of NiMo-doped catalysts. Low yield of methane (13.04c%) and high yield of condensable hydrocarbons products (25.82c%) with low selectivity of polyaromatics (4.37%) were obtained at 1.0 MPa H 2 and 400 °C catalytic temperature during lignin catalytic hydropyrolysis over Ni 1 Mo/ZrO 2. The hydrodeoxygenation activity of Ni x Mo/ZrO 2 depends on Ni0, Mo4+, and Mo3+. The synergistic effect of Ni and Mo promotes the removal of the phenolic methoxy group. The increase in hydrogen pressure tends to make hydrogen to be consumed through hydrocracking and hydrogenation reactions. The influence of Ni 1 Mo/ZrO 2 on evolution of lignin hydropyrolysis volatiles was revealed. Ni shows strong activity in the removal of phenolic hydroxyl groups and benzene ring hydrogenation, while Mo tends to remove phenolic methoxy groups. [ABSTRACT FROM AUTHOR]

Pentaerythritol tetranitrate (PETN) has trace homolog impurities that can be detected by high-performance liquid chromatography–mass spectrometry. Consideration of observed impurity masses and candidate structures based on known pentaerythritol impurities allows identification of 22 compounds in the data. These are all consistent with either fully nitrated homologs or derivatives substituted with methyl, methoxy, or hydroxyl groups in place of a nitric ester. Examining relative impurity concentrations in three starting batches of PETN and six subsequently processed batches shows that it is possible to use relative concentration profiles as a fingerprint to differentiate batches and follow them through recrystallization steps. [ABSTRACT FROM AUTHOR]

Two synthetic approaches to the achiral quinoline fragment of simeprevir are described. Both approaches are based on the synthesis of methyl 4-hydroxy-7-methoxy-8-methylquinoline-2- carboxylate, protection of its 4-hydroxyl group, and construction of the thiazole ring from the ester group at the 2-position. The last step is acid deprotection of the 4-hydroxyl protecting group. [ABSTRACT FROM AUTHOR]

By the introduction of methoxycarbonyl-methoxy groups and hydroxyl groups into a pillar structure, a pillararene entirely with two types of functional groups was successfully prepared, which can form a stable 1:1 complex with a bis(imidazolium) salt in CHCl3/acetone solution ( V: V=1:1). [ABSTRACT FROM AUTHOR]

In order to characterize polybrominated diphenyl ethers (PBDEs), and hydroxylated and methoxylated PBDEs (OH-PBDEs and MeO-PBDEs) in the soil–plant system, soil and plant samples were collected from an e-waste recycling area in China. Forty one PBDEs, twelve OH-PBDEs and MeO-PBDEs were detected in the soil and plant samples. Concentrations of PBDEs in roots were significantly correlated to their concentrations in the soils, but the percentages of lower brominated congeners in the plants were higher than those in the soils. Significant positive linear relationships exist between concentrations of ∑OH-PBDEs and ∑MeO-PBDEs with higher levels of ∑MeO-PBDEs than those of ∑OH-PBDEs in the soils, plant roots and leaves. A majority of the OH-/MeO-PBDEs had the hydroxyl or methoxy group at the ortho-positions to the biphenyl bond for most of the plant species. However the occurrence of meta- and para- substituted OH-/MeO-PBDEs in soils and plants were also confirmed. [Copyright &y& Elsevier]

Abstract: The present work describes the preparation of a novel series of compounds based on the structure of goniothalamin (1), a natural styryl lactone with known cytotoxic and antiproliferative activities against a variety of cancer cell lines. A focused library of 17 goniothalamin analogues displaying the 5-methyl-2,5-dihydrofuran-2-one motif were prepared, and their cytotoxicity evaluated. While the analogues bearing methoxy and/or hydroxy groups on the aromatic moiety usually were at least three times less potent than the lead compound (1), ortho and para-trifluoromethyl analogues 10 and 11 exhibited levels of cytotoxicity similar to goniothalamin (1) against most cancer cell lines evaluated. One could suggest that the electronic effect of the trifluoromethyl group activates the inhibitor’s electrophilic site via reduction of the electron density of the α,β-unsaturated ester oxygen atom. These results provide new information on the structure activity relationship of these α,β-unsaturated styryl lactones, thereby further focusing the design of novel candidates. [Copyright &y& Elsevier]

Understanding the abundances of molecules in dense interstellar clouds requires knowledge of the rates of gas-phase reactions between uncharged species. However, because of the low temperatures within these clouds, reactions with an activation barrier were considered too slow to play an important role. Here we show that, despite the presence of a barrier, the rate coefficient for the reaction between the hydroxyl radical (OH) and methanol-one of the most abundant organic molecules in space-is almost two orders of magnitude larger at 63 K than previously measured at ∼200 K. We also observe the formation of the methoxy radical product, which was recently detected in space. These results are interpreted by the formation of a hydrogen-bonded complex that is sufficiently long-lived to undergo quantum-mechanical tunnelling to form products. We postulate that this tunnelling mechanism for the oxidation of organic molecules by OH is widespread in low-temperature interstellar environments. [ABSTRACT FROM AUTHOR]

A series of naphthoquinone-benzothiazole conjugates were synthesized as algicides, and their efficacies against harmful algal blooming species, such as Chattonella marina, Heterosigma akashiwo and Cochlodinium polykrikoides, were examined. The introduction of substituted benzothiazole at the C2 position of 1,4-naphthoquinone (compounds 1- 9) resulted in higher algicidal activity against C. polykrikoides than the C6 conjugates (compounds 10- 20). On the other hand, of the C6 conjugates, compounds 11 and 12 exhibited better algicidal activity against H. akashiwo, C. marina, and C. polykrikoides than the C2 conjugates. Further structure-activity analysis indicated that a replacement of the methoxy groups with hydroxyl groups (compounds 21- 26) decreased the algicidal activity significantly. Among the various synthetic naphthoquinonebezothiazole conjugates tested, compound 12 was found to affect the most significant decrease in the level of C. polykrikoides growth, with an IC of 0.19 μM. Compound 11 was found to be the most potent inhibitor against H. akashiwo and C. polykrikoides, with IC values of 0.32 and 0.12 μM, respectively. Overall, these results highlight a possible method for controlling and inhibiting red tide forming algae using NQ derivatives. [ABSTRACT FROM AUTHOR]

The antiparasitic (antihymenolepiatic and antileishmaniatic) activity of several N-benzyl derivatives of the alkaloid cytisine and 3-bromocytisine was studied. The structure-activity relationship in the series of synthesized compounds was analyzed. It was established that their activity depended on the presence and location of the halide atom in the molecular structure to a greater extent than the on presence of hydroxy or methoxy groups. [ABSTRACT FROM AUTHOR]

Abstract: Surface modification of TiO2 nanoparticles with 3-methacrylic acyloxy propyl trimethoxysilane (KH570) was carried out in the liquid phase. As additives, the modified TiO2 nanoparticles were employed as charge control agents (CCAs) in the toner. The hydroxyl groups on the surface of TiO2 nanoparticles can interact with methoxy groups of KH570 and an organic coating layer formed. The Tih name="sbnd" />Si bond was testified by Fourier transform infrared spectra (FTIR). Through transmission electron micrograph (TEM) observation, it was found that the organic coating layer was about ∼3.1nm and the dispersibility of the modified TiO2 nanoparticles were obviously improved. Static water contact angle was used to investigate the wettability of the modified TiO2 surfaces. The results indicated that the hydrophobicity of the modified TiO2 nanoparticle surfaces could be effectively improved as the amount of the coated KH570 increased. The specific surface area (SSA) of the modified TiO2 was determined by Brunauer–Emmet–Teller (BET) method. Surface morphology of the modified toner and the toner charge were investigated by scanning electron microscopy (SEM) and electrometer, respectively. The modified toner showed smoother surface and the toner charge was adjusted by the modified TiO2 nanoparticles. The charge-to-mass ratio (Q/M) values shifted to the negative direction, for example −13.25μC/g, with an increasing coated KH570, probably due to the OH groups existing on the surface of TiO2. [Copyright &y& Elsevier]

Abstract: A hydroponic experiment was conducted to investigate the debrominated, hydroxylated and methoxylated metabolism of polybrominated diphenyl ethers (PBDEs, BDE-15, -28 and -47) in maize. A total of six debrominated metabolites (de-PBDEs), seven hydroxylated PBDEs (OH-PBDEs, including two unidentified OH-di-PBDEs and one unidentified OH-tri-PBDE) and four methoxylated PBDEs (MeO-PBDEs) were determined in the exposed plants. The metabolic products were detected in maize only after 12h of exposure to the PBDEs. However, the concentration of each type of the metabolites (de-PBDEs, OH-PBDEs or MeO-PBDEs) decreased at the later exposure time, possibly due to further metabolism. The removal of a bromine atom or the introduction of a hydroxyl/methoxy group was easier at the ortho-positions on the biphenyl structure than at the para-positions. Concentration ratios of the total debrominated, hydroxylated or methoxylated metabolites to the parent congener (BDE-28 or -47) generally followed the order of leaves>stems≫roots, and MeO-PBDEs>de-PBDEs≫OH-PBDEs. These results suggest that metabolism occurred preferentially in leaves and stems than in roots. Less transformation and shorter elimination half-life of OH-PBDEs would contribute to the lower concentrations of OH-PBDEs than of de-PBDEs or MeO-PBDEs in maize. [Copyright &y& Elsevier]

Abstract: The inclusion complexes of highly potent anti-HIV agent, UC781, with β-cyclodextrin (βCD), 2,6-dimethyl-β-cyclodextrin (MβCD), and 2-hydroxypropyl-β-cyclodextrin (HPβCD) in aqueous solution were investigated by molecular dynamics simulations. Simulations show that the phenyl ring of UC781 is trapped inside CD cavities, while the NH group of UC781 interacts with secondary hydroxyl groups at the wider rim of CDs. The different types of CDs directly affect the binding energy and the stability of the inclusion complexes. MβCD provides the most stable inclusion complex of UC781 among all CDs in this study due to the effect of methoxy groups (–OCH3) at C2 and C6 positions on the glucopyranose of CDs. Structure analysis of CDs and the orientation of UC781 inside CD cavities as well as the effects of aqueous solution to the inclusion complexes of UC781/CDs are discussed. Results of this study have provided an agreeable output; therefore, a reliable prediction method for other drug/CD inclusion complex formations is introduced. [Copyright &y& Elsevier]

Dihydrobenzofurans containing carbomethoxy-ethenyl at 2-position and phenyl and hydroxyl at 3-position were synthesized by photochemical methods and screened for antibacterial activity. These dihydrobenzofurans were moderately active against bacteria, both Gram-positive ( Staphylococcus aureus) and Gram-negative ( Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa), while compound 3-(6-chloro-3-hydroxy-3-phenyl-2,3-dihydrobenzofuran-2-yl)acrylic acid methyl ester showed promising activity against both the Gram-positive and Gram-negative bacteria. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

For the first time, 2-O-methyl- (2MC)and 3,6-di-O-methyl-cellulose (36MC) were synthesizedvia 3-O-allyl- and 3-O-methyl-cellulose,respectively.Position 6 of 3-O-allyl- and 3-O-methyl-cellulose was protected with the 4-methoxytrityl groups.The reaction time and temperature were optimized to achieve a highregioselectivity at C-6 and to prevent the introduction of the 4-methoxytritylgroup at C-2 of the polymer. It was found that the substituent atC-3 of 3-O-functionalized celluloses influenced thereactivity of the hydroxyl group at C-6. The structure was characterizedby means of 1H and 13C NMR spectroscopy of theacetates of 2MC and 36MC. 2MC and 36MC were soluble in water and didnot show thermoreversible gelation. [ABSTRACT FROM AUTHOR]

It was established by NMR spectroscopy that the catalytic hydrogenation of 3-methoxy-7α-methyl-6-oxa-14β-estra-1,3,5(10),8-tetraen-17-one leads to the formation of 3-methoxy-7α-methyl-6-oxa-9β,14β-estra-1,3,5(10)-trien-17-one, the structure of which was investigated in solution. The corresponding analog with a free hydroxyl group at the position 3 possesses an antiradical activity at the absence of uterotropic effect. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the ability of an extracellular fungal laccase (LAC) to form colored products from simple non-colored organic precursors. Thirty different phenolic and non-phenolic precursors ( o-, m-, and p-methoxy-, hydroxy-, sulfonic-, and amino-substituted) were tested as single and coupled substrates in a LAC-catalyzed oxidation. The findings show that LAC catalyzes the formation of colored products (from yellow/brown to red and blue) by oxidation of single substrates that are benzene derivatives containing at least two substituents comprised of amino, hydroxy, and methoxy groups. All precursors were tested by cyclic voltammetry and the correlation between their structure and redox potential, and the possibility of their transformation into colored products by fungal LAC was found. Colored products were yielded from single substrates possessing a value of the oxidation peak ( Eo) lower than 1,150 mV vs. normal hydrogen electrode (NHE). Substrates with an oxidation peak higher than 1,150 mV vs. NHE were transformed by LAC into colored compounds only in the presence of an additional precursor characterized by a low value of Eo and the presence of reactive substituents such as methoxy, hydroxy, and amino groups. Therefore, additional hydroxylation, methoxylation, and amination of phenolic and non-phenolic substrates may represent a strategy to increase the range of these compounds as potential dyes precursors. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2012 [ABSTRACT FROM AUTHOR]

Established roles for PI3K and MAPK signaling pathways in tumorigenesis has prompted extensive research towards the discovery of small-molecule inhibitors as cancer therapeutics. However, significant compensatory regulation exists between these two signaling cascades, leading to redundancy among survival pathways. Consequently, initial clinical trials aimed at either PI3K or MEK inhibition alone have proven ineffective and highlight the need for development of targeted and innovative therapeutic combination strategies. We designed a series of PI3K inhibitor derivatives wherein a single morpholine group of the PI3K inhibitor ZSTK474 was substituted with a variety of 2-aminoethyl functional groups. Analogs with pendant hydroxyl or methoxy groups maintained low nanomolar inhibition towards PI3Kα, PI3Kγ, and PI3Kδ isoforms in contrast to those with pendant amino groups which were significantly less inhibitory. Synthesis of prototype PI3K/MEK bifunctional inhibitors (6r , 6s) was guided by the structure-activity data, where a MEK-targeting inhibitor was tethered directly via a short PEG linker to the triazine core of the PI3K inhibitor analogs. These compounds (6r, 6s) displayed nanomolar inhibition towards PI3Kα, δ , and MEK (IC 50 ∼105–350 nM), and low micromolar inhibition for PI3Kβ and PI3Kγ (IC 50 ∼1.5–3.9 μM) in enzymatic inhibition assays. Cell viability assays demonstrated superior anti-proliferative activity for 6s over 6r in three tumor-derived cell lines (A375, D54, SET-2), which correlated with inhibition of downstream AKT and ERK1/2 phosphorylation. Compounds 6r and 6s also demonstrated in vivo tolerability with therapeutic efficacy through reduction of kinase activation and amelioration of disease phenotypes in the JAK2V617F mutant myelofibrosis mouse cancer model. Taken together, these results support further structure optimization of 6r and 6s as promising leads for combination therapy in human cancer as a new class of PI3K/MEK bifunctional inhibitors. [Display omitted] • ZSTK474 analogs with pendant acyclic groups replacing a single morpholine group. • Optimal PI3K isoform inhibition was found with pendant hydroxyl or methoxy groups. • Prototype PI3K/MEK bifunctional inhibitors (6r , 6s) were synthesized. • Demonstrated anti-proliferative activity in tumor-derived cell lines. • Achieved therapeutic activity in mouse cancer model with reduced kinase activation. [ABSTRACT FROM AUTHOR]