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Electrochemically exfoliated graphene for nanosensor applications
Water dispersible graphene layer are the excellent nano materials used for wide range of electronic applications. High quality graphene was synthesized by an eco-friendly, easy and cost effective electrochemical exfoliation method. In this work, graphite rod was used both as an anode and cathode for the production of graphene. Potassium sulphate (K2SO4) was used as an intercalating agent. Electrochemically exfoliated graphene (EEG) was coated on glassy carbon electrode (GCE) and evaluated towards the electrochemical oxidation of vanillin and L-phenylalanine. The fabricated electrode was able to detect vanillin and L-Phenylalanine as low as 0.2 μM with signal to noise ratio of 3. A significant increase in the current was observed for the graphene coated electrode for both vanillin and L-phenylalanine when compared to bare Glassy electrode. The finding clearly demonstrated the higher detection capability, selectivity and reproducibility of EEG.
Sivasankar,Senthilkumar,Vivekananth,Kalaivani,Sivakumar
p. 7097 - 7104
(2019)
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Flavonoids as antioxidants
Spectral, acid-base, and redox properties of the phenoxyl radicals derived from 3,4-dihydroxybenzene derivatives and selected flavonoids were studied by pulse radiolysis of aqueous solutions. From the pH-dependent changes in the phenoxyl spectra, the dissociation constants were derived. The pK(a) values for the deprotonation of the 3'-OH group in the catechin (pK(a) = 4.6) and rutin (pK(a) = 4.3) radicals are similar to the pK(a) value of the 3,4-dihydroxybenzoate radicals, pK(a) = 4.2, which is expected from their similar electronic structures. Deprotonation of 5- and 7-OH in the catechin and rutin and of 5-OH in the hesperidin radicals has no effect on the radical spectra, which is explained by the inefficient coupling of the A-ring of the flavonoid radicals with the unpaired electron. Because of favorable reduction potentials of the phenoxyl radicals, E7 = 0.56-0.7 V vs NHE, flavonoids may act as efficient antioxidants of alkylperoxyl and superoxide/hydroperoxyl radicals. The ac kinetic conductivity method was developed for the measurements of the low reaction rate constants of the superoxide radical reactions with flavonoids and phenols in aqueous solutions at pH 10. The rates of the superoxide radical reactions with flavonoids, k = 3 x 102-5.1 x 104 M-1 s-1, depend on the redox properties and the charge of the flavonoids. The highest rates are measured for the oxidation of quercetin and rutin, whereas the lowest are those for the B-ring monosubstituted derivatives, with substantially higher redox potentials. Uncharged catechin at pH 7 reacts at k = 6.6 x 104 M-1 s-1, whereas the rate at pH 10, where catechin is doubly negatively charged, is approximately 4 times lower, k = 1.8 x 104 M-1 s-1. The activation parameters of the oxidation of rutin and trolox at pH 10 and methylgallate at pH 7 were determined in an attempt to understand why the rates of the superoxide reactions are low despite high driving forces of ΔE ≥ 0.4 V. Low activation enthalpies, ΔH(paragraph) 2.3-3.6 kcal/mol, and negative activation entropies, ΔS(paragraph) = -25-28 cal/(mol K), point to an inner-sphere electron-transfer mechanism.
Jovanovic, Slobodan V.,Steenken, Steen,Tosic, Mihajlo,Marjanovic, Budimir,Simic, Michael G.
p. 4846 - 4851
(1994)
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Stereoselective synthesis of trans-dihydronarciclasine derivatives containing a 1,4-benzodioxane moiety
Abstract: Some new trans-dihydronarciclasine derivatives containing a 1,4-benzodioxane moiety were stereoselectively synthesised using our feasible and efficient method developed recently. These new phenanthridone alkaloid analogues were obtained in both racemic and optically active forms. High enantioselectivities (up to 99% ee) were achieved by applying (8S,9S)-9-amino(9-deoxy)epiquinine as an organocatalyst. Due to a side reaction, various methoxyphenanthridine regioisomers were also prepared which afforded further synthetic trans-dihydronarciclasine analogues modified in the ring A of the phenanthridone scaffold. Graphical abstract: [Figure not available: see fulltext.].
Varró, Gábor,Pogrányi, Balázs,Grün, Alajos,Simon, András,Heged?s, László,Kádas, István
p. 2265 - 2285
(2018)
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Polyoxometalates as solution-phase electrocatalytic mediators for reduced electrode fouling and the improved oxidative response of phenols
The electrochemical oxidation of phenols typically passivates electrodes, due to the reactive one-electron oxidation intermediate, a phenoxyl radical cation. Here, we show that the addition of polyoxometalates to the electrolyte can prevent electrode passivation via an EC'E mechanism; the initial oxidation is unchanged, but oxidation of the phenoxyl radical intermediate is mediated. As such the electrochemistry assumes an ideal EE process, as confirmed by cyclic voltammetric simulation, with no electrode fouling on the voltammetric timescale. Bulk electrolysis of phenolic molecules can even be performed to isolate solution-phase products. This is exemplified by the scenario of vanillin (phenolic compound) and phosphotungstic acid (H3[PW12O40], a polyoxometalate).
Hossain, Md. Mokarrom,Aldous, Leigh
p. 32 - 35
(2016)
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On the difference in decomposition of taxifolin and luteolin vs. fisetin and quercetin in aqueous media
Abstract: The decomposition of flavonols quercetin and fisetin, flavone luteolin and flavanone taxifolin was studied in slightly alkaline solution under ambient conditions. The study was based on spectrophotometry and high-pressure liquid chromatography. Products formed by atmospheric oxygen oxidation and hydrolysis were identified by HPLC–DAD and HPLC–ESI-MS/MS. Only small differences in the chemical structure of flavonoids resulted in extremely variable oxidation pathways and products. Oxidation of flavonols led to the formation of both a benzofuranone derivative and several open structures. On the contrary, the benzofuranone derivative was not found as a product of taxifolin and luteolin oxidative decomposition. These compounds were oxidized to their hydroxylated derivatives and typical open structures. Quercetin was not identified as a possible oxidation product of taxifolin. Graphical Abstract: [Figure not available: see fulltext.]
Sokolová, Romana,Rame?ová, ?árka,Kocábová, Jana,Kolivo?ka, Viliam,Degano, Ilaria,Pitzalis, Emanuela
p. 1375 - 1383
(2016)
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Total synthesis of (±)-fumimycin and analogues for biological evaluation as peptide deformylase inhibitors
A concise 7-step total synthesis of (±)-fumimycin in 11.6% overall yield is reported. An acid-catalyzed intramolecular aza-Friedel–Crafts cyclization was developed to construct the benzofuranone skeleton of the natural product bearing an α,α-disubstituted amino acid moiety in a single step. Regioselective chlorination followed by a Suzuki–Miyaura cross-coupling rapidly enabled the preparation of a library of analogues which were evaluated against peptide deformylase for antibacterial activity.
Zaghouani, Mehdi,B?geholz, Lena A.K.,Mercier, Evan,Wintermeyer, Wolfgang,Roche, Stéphane P.
p. 3216 - 3230
(2019)
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A method of synthesis of piperonolamine
The present invention belongs to the field of organic chemical synthesis, specifically relates to a synthesis method of piperine, comprising: using catechol as a raw material to prepare piperonaldehyde; β - nitro-3,4-dioxenosylstyrene prepared with piperonaldehyde; β - nitro -3,4-dioxenesimethylenestyrene to obtain piperine ethylamine. Among them, the preparation of piperaldehyde from catechol as raw materials includes two ways: (1) catechol→3,4-dihydroxymandelic acid→3,4-dihydroxybenzaldehyde→ piperaldehyde; (2) catechol→ piperine ring → piperine. The raw materials used in the present invention are safe and readily available, low cost; the reaction conditions are mild, the operation is simple, the chemical yield is high, and the intermediate reagents are easy to recover; suitable for industrial production.
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(2022/01/07)

A synthetic preparation method for small carbags hydrochloric acid
The present invention belongs to the field of organic chemistry, relates to a method of synthesizing berberine hydrochloride, comprising: S1: with 5-halo-o-quinoastearaldehyde and piperine ethylamine to obtain N- [2-(3,4-dimethoxyphenyl-5-yl) ethyl] -1- (5-halo-2,3-dimethoxybenzyl) methylimide; S2: to obtain 2- (3,4-diimoxyphenyl) -N- (5-bromo-2,3-dimethoxybenzyl) ethylamine; S3: to obtain 2-(3,4-dimethoxyphenyl) -N- (5-bromo-2 S4: to obtain 12-halogenated berberine derivative; S5: to obtain berberine. The present invention is free from the application of the by-product o-vanillin synthesis of o-resveratal raw material constraints, synthesis of 5- substitute o-resveratal and piperine ethylamine, and the use of the two preparation of berberine hydrochloride, with raw materials readily available, mild reaction conditions, easy to operate, high chemical yield, low cost and other advantages.
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(2021/12/08)

Thiols Act as Methyl Traps in the Biocatalytic Demethylation of Guaiacol Derivatives
Demethylating methyl phenyl ethers is challenging, especially when the products are catechol derivatives prone to follow-up reactions. For biocatalytic demethylation, monooxygenases have previously been described requiring molecular oxygen which may cause oxidative side reactions. Here we show that such compounds can be demethylated anaerobically by using cobalamin-dependent methyltransferases exploiting thiols like ethyl 3-mercaptopropionate as a methyl trap. Using just two equivalents of this reagent, a broad spectrum of substituted guaiacol derivatives were demethylated, with conversions mostly above 90 %. This strategy was used to prepare the highly valuable antioxidant hydroxytyrosol on a one-gram scale in 97 % isolated yield.
Grimm, Christopher,Kroutil, Wolfgang,Pompei, Simona,Schiller, Christine,Schober, Lukas
p. 16906 - 16910
(2021/07/02)

Herbicide based on haloxyfop, flumetsulam and halosulfuron-methyl
The invention discloses a herbicide based on haloxyfop, flumetsulam and halosulfuron-methyl. The herbicide is prepared from the following raw materials in parts by weight: 1-15 parts of haloxyfop-R-methyl, 1-15 parts of flumetsulam, 1-37 parts of halosulfuron-methyl, 1-2 parts of a modified antioxidant, 10-12 parts of borax, 6-8 parts of a surfactant, 10-12 parts of triethanolamine, 10-12 parts of vegetable oil and 40-42 parts of deionized water. After the haloxyfop-R-methyl, the flumetsulam and the halosulfuron-methyl are mixed, the effects are complementary, the weeding spectrum is wider, the weeding activity is high, the weeding effect is more excellent. In addition, the modified antioxidant is added into the herbicide formula, so that the composite herbicide has the effects of resisting oxidation aging and ultraviolet aging, effective components are prevented from decomposing and losing efficacy in the presence of light, the pesticide effect is kept lasting, and the application prospect and popularization value are remarkably improved.
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Paragraph 0038; 0045; 0053; 0060; 0068; 0075

(2021/06/21)

Efficient demethylation of aromatic methyl ethers with HCl in water
A green, efficient and cheap demethylation reaction of aromatic methyl ethers with mineral acid (HCl or H2SO4) as a catalyst in high temperature pressurized water provided the corresponding aromatic alcohols (phenols, catechols, pyrogallols) in high yield. 4-Propylguaiacol was chosen as a model, given the various applications of the 4-propylcatechol reaction product. This demethylation reaction could be easily scaled and biorenewable 4-propylguaiacol from wood and clove oil could also be applied as a feedstock. Greenness of the developed methodversusstate-of-the-art demethylation reactions was assessed by performing a quantitative and qualitative Green Metrics analysis. Versatility of the method was shown on a variety of aromatic methyl ethers containing (biorenewable) substrates, yielding up to 99% of the corresponding aromatic alcohols, in most cases just requiring simple extraction as work-up.
Bomon, Jeroen,Bal, Mathias,Achar, Tapas Kumar,Sergeyev, Sergey,Wu, Xian,Wambacq, Ben,Lemière, Filip,Sels, Bert F.,Maes, Bert U. W.
supporting information
p. 1995 - 2009
(2021/03/26)

Oxygen-Free Regioselective Biocatalytic Demethylation of Methyl-phenyl Ethers via Methyltransfer Employing Veratrol- O-demethylase
The cleavage of aryl methyl ethers is a common reaction in chemistry requiring rather harsh conditions; consequently, it is prone to undesired reactions and lacks regioselectivity. Nevertheless, O-demethylation of aryl methyl ethers is a tool to valorize natural and pharmaceutical compounds by deprotecting reactive hydroxyl moieties. Various oxidative enzymes are known to catalyze this reaction at the expense of molecular oxygen, which may lead in the case of phenols/catechols to undesired side reactions (e.g., oxidation, polymerization). Here an oxygen-independent demethylation via methyl transfer is presented employing a cobalamin-dependent veratrol-O-demethylase (vdmB). The biocatalytic demethylation transforms a variety of aryl methyl ethers with two functional methoxy moieties either in 1,2-position or in 1,3-position. Biocatalytic reactions enabled, for instance, the regioselective monodemethylation of substituted 3,4-dimethoxy phenol as well as the monodemethylation of 1,3,5-trimethoxybenzene. The methyltransferase vdmB was also successfully applied for the regioselective demethylation of natural compounds such as papaverine and rac-yatein. The approach presented here represents an alternative to chemical and enzymatic demethylation concepts and allows performing regioselective demethylation in the absence of oxygen under mild conditions, representing a valuable extension of the synthetic repertoire to modify pharmaceuticals and diversify natural products.
Grimm, Christopher,Lazzarotto, Mattia,Pompei, Simona,Schichler, Johanna,Richter, Nina,Farnberger, Judith E.,Fuchs, Michael,Kroutil, Wolfgang
p. 10375 - 10380
(2020/10/02)

Anchimerically Assisted Selective Cleavage of Acid-Labile Aryl Alkyl Ethers by Aluminum Triiodide and N, N-Dimethylformamide Dimethyl Acetal
Aluminum triiodide is harnessed by N,N-dimethylformamide dimethyl acetal (DMF-DMA) for the selective cleavage of ethers via neighboring group participation. Various acid-labile functional groups, including carboxylate, allyl, tert-butyldimethylsilyl (TBS), and tert-butoxycarbonyl (Boc), suffer the conditions intact. The method offers an efficient approach to cleaving catechol monoalkyl ethers and to uncovering phenols from acetal-type protecting groups such as methoxymethyl (MOM), methoxyethoxymethyl (MEM), and tetrahydropyranyl (THP) chemoselectively.
Sang, Dayong,Yue, Huaxin,Zhao, Zhengdong,Yang, Pengtao,Tian, Juan
p. 6429 - 6440
(2020/07/14)

Selective ether bond breaking method of aryl alkyl ether
The invention discloses a selective aryl alkyl ether cracking method, which comprises that aryl alkyl ether, aluminum iodide and an additive are subjected to a selective ether bond cleavage reaction in an organic solvent at a temperature of -20 DEG C to a reflux temperature to generate phenol and derivatives thereof. The method is mild in condition and simple and convenient to operate, is suitablefor cracking aryl alkyl ether containing o-hydroxyl and o-carbonyl and acetal ether, and can also be used for removing tertiary carbon hydroxyl protecting groups with higher steric hindrance, such astriphenylmethyl, tertiary butyl and the like.
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Paragraph 0137-0141

(2020/09/16)

Method for preparing aldehyde compounds through photocatalytic oxidation cracking β - hydroxyl compound C-C bond
The invention provides a method for preparing aldehydes from C-C bonds of beta-hydroxy compounds by photocatalytic oxidative cracking. According to the method, the beta-hydroxy compounds are taken asa substrate, oxygen-containing gas is taken as an oxygen source, and C-C bond cracked products, namely, corresponding aldehydes can be generated under illumination in presence of a catalyst. The conditions are mild, the oxidation efficiency and the product yield are high, and the oxygen-containing gas is taken as the oxygen source under the illumination condition, so that the method is economical,environmentally friendly and green, meets the strategy of sustainable developed energy and has broad application prospect.
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Paragraph 0062-0063

(2020/07/29)

Cleavage of Catechol Monoalkyl Ethers by Aluminum Triiodide-Dimethyl Sulfoxide
Using eugenol and vanillin as model substrates, a practical method is developed for the cleavage o -hydroxyphenyl alkyl ethers. Aluminum oxide iodide (O=AlI), generated in situ from aluminum triiodide and dimethyl sulfoxide, is the reactive ether cleaving species. The method is applicable to catechol monoalkyl ethers as well as normal phenyl alkyl ethers for the removal of methyl, ethyl, isopropyl, and benzyl groups. A variety of functional groups such as alkenyl, allyl, amide, cyano, formyl, keto, nitro, and halogen are well tolerated under the optimum conditions. Partial hydrodebromination was observed during the demethylation of 4-bromoguaiacol, and was resolved using excess DMSO as an acid scavenger. This convenient and efficient procedure would be a practical tool for the preparation of catechols.
Sang, Dayong,Tian, Juan,Tu, Xiaodong,He, Zhoujun,Yao, Ming
p. 704 - 712
(2019/01/23)

Preparation method of erlotinib hydrochloride intermediate
The invention provides a preparation method of an erlotinib hydrochloride intermediate. The preparation method comprises following steps: removing the methyl of vanillin, performing esterification, converting an aldehyde group into a nitrile group, and carrying out nitration, reduction, hydrolysis, and ring forming reactions. The reaction route is represented in the description. The technology isreasonable, the operation is simple, the cost is low, and the reaction yield is high.
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Paragraph 0024; 0031-0032

(2019/05/08)

Coenzyme A-Conjugated Cinnamic Acids – Enzymatic Synthesis of a CoA-Ester Library and Application in Biocatalytic Cascades to Vanillin Derivatives
We present a bioorthogonal method for the ligation of coenzyme A (CoA) with cinnamic acids. The reaction, which is the initial step in the biosynthesis of a multitude of bioactive secondary metabolites, is catalyzed by a promiscuous plant ligase and yields CoA conjugates with different functionalization in high purity and without formation of by-products. Its applicability in biosynthetic cascades is shown for the direct transformation of cinnamic acids into natural benzaldehydes (like vanillin) or artificial derivatives (e. g. ethylvanillin). (Figure presented.).
Dippe, Martin,Bauer, Anne-Katrin,Porzel, Andrea,Funke, Evelyn,Müller, Anna O.,Schmidt, Jürgen,Beier, Maria,Wessjohann, Ludger A.
supporting information
p. 5346 - 5350
(2019/11/29)

A molybdenum based metallomicellar catalyst for controlled and chemoselective oxidation of activated alcohols in aqueous medium
A surfactant based oxodiperoxo molybdenum complex, which could activate molecular oxygen, has been employed as a catalyst for controlled oxidation of benzylic alcohols to corresponding carbonyls. The oxidation reactions were carried out under aqueous environment, however, in the absence of any extraneous base or co-catalyst. Sensitive/oxidizable functional groups like cyano, sulfide, hydroxyl, aryl-hydroxyl, alkene (internal/terminal), alkyne (internal/terminal), and acetal were tolerated during the transformations. Such selectivity is attributed to the mild nature of the catalyst. The methodology could also be scaled-up for multi-gram synthesis and the protocol is likely to find practical use since it requires an inexpensive recyclable-catalyst and easily available oxidant (under green conditions). A plausible mechanism is proposed with the help of preliminary computational study.
Thiruvengetam, Prabaharan,Chakravarthy, Rajan Deepan,Chand, Dillip Kumar
p. 123 - 133
(2019/07/19)

Cobalt tungsten oxide hydroxide hydrate (CTOHH) on DNA scaffold: An excellent bi-functional catalyst for oxygen evolution reaction (OER) and aromatic alcohol oxidation
A material with interdisciplinary properties is of wide interest for use in environmental applications. Currently, hydrogen generation by electrolysis and formation of carbonyl derivatives from alcohols are two different fields that focus on energy and environmental applications. In this work, a new material, Cobalt Tungsten Oxide Hydroxide Hydrate (CTOHH) on deoxyribonucleic acid (DNA) scaffold having chain-like morphology has been prepared for the first time by a facile microwave heating method. The same CTOHH was also prepared without the DNA scaffold and resulted in irregular aggregated molecular structures. Further, both CTOHH-DNA and CTOHH were converted into CoWO4-DNA and CoWO4, respectively by annealing them at a temperature of 600 °C. All the four catalysts were used for electrocatalytic oxygen evolution reaction (OER) and for oxidation of aromatic alcohols. In OER, CTOHH-DNA delivered fruitful results compared to all other electrocatalysts. For attaining a current density of 10 mA cm-2, it just required an overpotential of 355 mV with a Tafel slope value of 47.5 mV dec-1. Similarly, all four catalysts were also analyzed for selective and controlled oxidation of aromatic alcohols to their respective aldehydes and ketones using molecular oxygen as a green oxidant where CTOHH-DNA showed better results. Chemo-selectivity has been observed for CTOHH-DNA in the co-presence of hydroxyl and cyano functional groups. The durability of CTOHH-DNA was analyzed and it showed excellent catalytic activity retention up to five cycles.
Kumaravel, Sangeetha,Thiruvengetam, Prabaharan,Ede, Sivasankara Rao,Karthick,Anantharaj,Sam Sankar, Selvasundarasekar,Kundu, Subrata
supporting information
p. 17117 - 17131
(2019/11/26)

Ether bond cracking method of phenylalkyl ether
The invention discloses an ether bond cracking method of phenylalkyl ether. The method comprises the following steps: performing ether bond breaking reaction on phenylalkyl ether at -20 to reflux temperature in the presence of aluminium triiodide and dimethyl sulfoxide, thereby generating phenol and derivatives thereof. The method disclosed by the invention is mild in condition, simple and convenient for operation, high in yield, and extensive in applicable phenylalkyl ether range.
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Paragraph 0038-0040; 0044

(2018/11/26)

Imidazolium-Based Ionic Liquids as Efficient Reagents for the C?O Bond Cleavage of Lignin
The demethylation of lignin in ionic liquids (ILs) was investigated by using pure lignin model monomers and dimers together with dioxane-isolated lignins from poplar, miscanthus, and maize. Different methylimidazolium ILs were compared and the samples were treated with two different heating processes: microwave irradiation and conventional heating in a sealed tube. The conversion yield and influence of the treatment on the lignin structure were assessed by 31P NMR spectroscopy, size-exclusion chromatography, and thioacidolysis. The acidic methylimidazolium IL [HMIM]Br was shown to be an effective combination of solvent and reagent for the demethylation and depolymerization of lignin. The relatively mild reaction conditions, the clean work-up, and the ability to reuse the IL makes the described procedure an attractive and new green method for the conversion of lignin to produce phenol-rich lignin oligomers.
Thierry, Marina,Majira, Amel,Pégot, Bruce,Cezard, Laurent,Bourdreux, Flavien,Clément, Gilles,Perreau, Fran?ois,Boutet-Mercey, Stéphanie,Diter, Patrick,Vo-Thanh, Giang,Lapierre, Catherine,Ducrot, Paul-Henri,Magnier, Emmanuel,Baumberger, Stéphanie,Cottyn, Betty
p. 439 - 448
(2018/02/06)

Temperature-Directed Biocatalysis for the Sustainable Production of Aromatic Aldehydes or Alcohols
The biosynthesis of aromatic aldehydes and alcohols from renewable resources is currently receiving considerable attention because of an increase in demand, finite fossil resources, and growing environmental concerns. Here, a temperature-directed whole-cell catalyst was developed by using two novel enzymes from a thermophilic actinomycete. Ferulic acid, a model lignin derivative, was efficiently converted into vanillyl alcohol at a reaction temperature at 30 °C. However, when the temperature was increased to 50 °C, ferulic acid was mainly converted into vanillin with a productivity of 1.1 g L?1 h?1. This is due to the fact that the redundant endogenous alcohol dehydrogenases (ADHs) are not active at this temperature while the functional enzymes from the thermophilic strain remain active. As the biocatalyst could convert many other renewable cinnamic acid derivatives into their corresponding aromatic aldehydes/alcohols, this novel strategy may be extended to generate a vast array of valuable aldehydes or alcohols.
Ni, Jun,Gao, Yan-Yan,Tao, Fei,Liu, Hong-Yu,Xu, Ping
supporting information
p. 1214 - 1217
(2018/01/27)

A phenyl alkyl ether ether linkage breaking method (by machine translation)
The invention discloses a phenyl alkyl ether ether linkage breaking method, the method is: in the organic solvent, in the presence of a mineral acid and the aluminium triiodide scavenging agent under the conditions of, phenyl ether in the - 20 °C to reflux temperature lower ether linkage breaking reaction, generating phenol and its derivatives. The mild conditions, the operation is simple, and the yield is high, the applicable phenyl ether range is wide. (by machine translation)
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Paragraph 0047-0049

(2018/04/01)

Pyridine Improves Aluminum Triiodide Induced Selective Cleavage of Alkyl o -Hydroxyphenyl Ethers: A Practical and Efficient Procedure for the Preparation of Hydroxychavicol by Demethylation of Eugenol
Demethylation of eugenol with aluminum triiodide is complicated by an unexpected hydrogenation side reaction. The hydrogenation proceeds through a cascade deprotonation, hydroiodination, and hydrogen-halogen exchange process, and can be prevented by suppressing the hydroiodination in advance. A practical demethylation procedure is thus developed that delivers hydryoxychavicol in essentially quantitative yield by using pyridine as an additive. The method is selective towards cleaving alkyl o-hydroxyphenyl ethers and is compatible with a variety of functional groups.
Sang, Dayong,Yao, Ming,Tian, Juan,Chen, Xiaoman,Li, Li,Zhan, Hongju,You, Linhong
p. 138 - 142
(2016/12/26)

Ether bond rupturing method for ortho-hydroxyl phenyl alkyl ether
The invention discloses an ether bond rupturing method for ortho-hydroxyl phenyl alkyl ether. The method comprises the following steps that in a solvent, an ether bond rupturing reaction occurs to ortho-hydroxyl aryl alky ether at the temperature ranging from minus 20 DEG C to the catalyst reflux temperature under the existence of alkali and a catalyst aluminum triiodide, and catechol and derivatives thereof are generated. The method is simple, reaction conditions are simple, and operation is easy; besides, the yield is high, and the applicable ortho-hydroxyl phenyl alkyl ether range is wide.
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Paragraph 0045; 0046; 0047; 0048; 0049; 0050

(2017/05/27)

Carbodiimides as Acid Scavengers in Aluminum Triiodide Induced Cleavage of Alkyl Aryl Ethers
A practical procedure for the cleavage of alkyl aryl ethers containing labile functional groups has been developed using aluminum triiodide as the ether cleaving reagent. Carbodiimides, typically used as dehydration reagents for the coupling of amines and carboxylic acids to yield amide bonds, are found to be effective hydrogen iodide scavengers that prevent acid-labile groups from deterioration. The method is applicable to variant alkyl aryl ethers such as eugenol, vanillin, ortho -vanillin and methyl eugenol. Suitable substrates are not limited to alkyl o -hydroxyphenyl ethers.
Sang, Dayong,Wang, Jiahui,Zheng, Yun,He, Jianyuan,Yuan, Caili,An, Qing,Tian, Juan
p. 2721 - 2726
(2017/06/13)

Ether bond breakage method for phenylalkyl ethers
The invention discloses an ether bond breakage method for phenylalkyl ethers. The method comprises the step: subjecting the phenylalkyl ethers to an ether bond breakage reaction at the temperature of -20 DEG C to reflux temperature in an organic solvent in the presence of aluminum triiodide and carbodiimide, so as to produce phenols and derivatives thereof. The method is moderate in conditions, simple and convenient in operation, high in yield and wide in applicable phenylalkyl ether range.
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Paragraph 0096-0098

(2017/07/19)

Bromophenol-oxazole compound and its use in drug for treatment on diabetes mellitus type 2
The invention relates to a chemical total synthesis method of novel bromophenol-oxazole PTP1B and its use in a drug for treatment on diabetes mellitus type 2. The PTP1B inhibitor has a structural formula shown in the description. The compound improves insulin receptor sensibility through inhibiting the activity of protein tyrosine phosphatase 1B and has good treatment effects on insulin resistance-type diabetes mellitus type 2.
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Paragraph 0020-0022; 0038-0040

(2017/08/19)

A rapid, solvent-free deprotection of methoxymethyl (MOM) ethers by pTSA; An eco-friendly approach
Background: Ease of preparation and alkaline stability of methoxymethyl (MOM) makes it an important hydroxyl protecting group. A number of methods are available for the deprotection of MOM. Though the methods are good in general, they use solvents, require prolonged reaction time and tedious work up. A solvent free, solid phase, fast deprotection of MOM has been developed and is the major theme of this paper. Methods: A mixture of MOM protected compounds and pTSA is triturated in a mortar (5 min) and left at room temperature for 30 min. On addition of water (4°C), pTSA, methanol and formaldehyde dissolved leaving the products as precipitates. Results: A series of different MOM ethers were deprotected by this method in good to excellent yield (85-98%). The compatibility of MOM in the presence of other protections such as methoxyl, benzyl, ester, amide, allyl and lactone was also established. Acetate protection is not stable under these conditions. Conclusion: An efficient, selective and high yielding deprotection MOM groups by pTSA under solvent free condition is described. The process is environment friendly since no solvent was used in the deprotection process. The reaction conditions are mild and should be useful for the deprotection of MOM derivatives of complex and labile molecules.
Pandurangan, Nanjan
p. 231 - 235
(2017/07/15)

Oxidative decarboxylation of arylacetic acids in water: One-pot transition-metal-free synthesis of aldehydes and ketones
One-pot transition-metal-free synthesis of aromatic aldehydes and ketones via oxidative decarboxylation of arylacetic acids in water is developed. Protocol relies on the direct decarboxylation of sp3-hybridized carbon in water without any over oxidation into carboxylic acids with minimal waste. Reaction mechanism is investigated and application of this protocol is demonstrated on a gram scale.
Mete, Trimbak B.,Khopade, Tushar M.,Bhat, Ramakrishna G.
supporting information
p. 2822 - 2825
(2017/06/27)

Method for preparing salvianolic acid A
The invention discloses a method for preparing salvianolic acid A. The method includes the following steps that firstly, salvianolic acid B is prepared into a solution with the concentration of 35-45 mg/mL by means of NaOH or NaHCO3 with the pH value of 3.5-4.5, the solution is placed in a subcritical water reaction kettle, after the temperature of a heating furnace reaches 170-190 DEG C and is stabilized, the reaction kettle is placed into the heating furnace, the reaction kettle is taken out after 50-70 min and placed in ice water bath or cold water to be cooled, the liquid is taken out and subjected to freeze-drying, and a crude product rich in salvianolic acid A is obtained; secondly, salvianolic acid A is separated and purified by means of high-speed countercurrent chromatography, wherein a solvent system is prepared from petroleum ether, ethyl acetate, n-butyl alcohol and water according to the ratio of 2:3:1:9, 10 mM of trifluoroacetic acid is added to an upper phase to form a stationary phase, 10 mM ammonia water is a lower phase and serves as a mobile phase, the volume of a high-speed countercurrent chromatography column is 200-400 mL, the sample loading amount is 1.0-1.2 g, the rotation speed is 600-1000 rpm, the flow speed is 1-4 mL/min, and the detection wavelength is 280 nm. The method is low in cost, easy to operate and high in efficiency, salvianolic acid crude extracts can be converted on a large scale, and a salvianolic acid A monomeric compound with the purity higher than 98% is separated and prepared.
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Paragraph 0027; 0028; 0029; 0030; 0031; 0032; 0033-0043

(2017/04/03)

Preparation method of erlotinib intermediate
The invention relates to a preparation method of an erlotinib intermediate. The method concretely comprises the following steps: 1, dissolving vanillin in an organic solvent I, adding aluminum trichloride, adding pyridine in a dropwise manner, and reacting to obtain ELTA; 2, dissolving the ELTA in an organic solvent II, adding 2-chloroethylmethyl ether, potassium carbonate and a phase transfer catalyst, and reacting to obtain ELTB; 3, adding the ELTB to water, adding an alkali and potassium permanganate, and reacting to obtain ELTC; 4, adding concentrated sulfuric acid to methanol in a dropwise manner, adding the ELTC to the above reaction system, and reacting to obtain ELTD; 5, adding concentrated sulfuric acid to concentrated nitric acid in a dropwise manner, dissolving the ELTD in an organic solvent IV, adding a prepared mixed acid to the reaction system, and reacting to obtain ELTE; 6, adding the ELTE, iron powder and ammonium chloride to an organic solvent V, adding concentrated hydrochloric acid in a dropwise manner, and reacting to obtain ELTF; and 7, adding the ELTF, trimethyl orthoformate and ammonium acetate to an organic solvent VI, and reacting to obtain the erlotinib intermediate.
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Paragraph 0015; 0060

(2016/10/10)

Novel multifunctional dopamine D2/D3receptors agonists with potential neuroprotection and anti-alpha synuclein protein aggregation properties
Our ongoing drug development endeavor to design compounds for symptomatic and neuroprotective treatment of Parkinson's disease (PD) led us to carry out a structure activity relationship study based on dopamine agonists pramipexole and 5-OHDPAT. Our goal was to incorporate structural elements in these agonists in a way to preserve their agonist activity while producing inhibitory activity against aggregation of α-synuclein protein. In our design we appended various catechol and related phenol derivatives to the parent agonists via different linker lengths. Structural optimization led to development of several potent agonists among which (?)-8a, (?)-14 and (?)-20 exhibited potent neuroprotective properties in a cellular PD model involving neurotoxin 6-OHDA. The lead compounds (?)-8a and (?)-14 were able to modulate aggregation of α-synuclein protein efficiently. Finally, in an in vivo PD animal model, compound (?)-8a exhibited efficacious anti-parkinsonian effect.
Luo, Dan,Sharma, Horrick,Yedlapudi, Deepthi,Antonio, Tamara,Reith, Maarten E.A.,Dutta, Aloke K.
p. 5088 - 5102
(2016/10/22)

The metabolic fate of ortho-quinones derived from catecholamine metabolites
ortho-Quinones are produced in vivo through the oxidation of catecholic substrates by enzymes such as tyrosinase or by transition metalions. Neuromelanin, a dark pigment present in the substantia nigra and locus coeruleus of the brain, is produced from dopamine (DA) and norepinephrine (NE) via an interaction with cysteine, but it also incorporates their alcoholic and acidic metabolites. In this study we examined the metabolic fate of ortho-quinones derived from the catecholamine metabolites, 3,4-dihydroxyphenylethanol (DOPE), 3,4-dihydroxyphenylethylene glycol (DOPEG), 3,4-dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylmandelic acid (DOMA). The oxidation of catecholic substrates by mushroom tyrosinase was followed by UV-visible spectrophotometry. HPLC analysis after reduction with NaBH4 or ascorbic acid enabled measurement of the half-lives of ortho-quinones and the identification of their reaction products. Spectrophotometric examination showed that the ortho-quinones initially formed underwent extensive degradation at pH 6.8. HPLC analysis showed that DOPE-quinone and DOPEG-quinone degraded with half-lives of 15 and 30 min at pH 6.8, respectively, and >100 min at pH 5.3. The major product from DOPE-quinone was DOPEG which was produced through the addition of a water molecule to the quinone methide intermediate. DOPEG-quinone yielded a ketone, 2-oxo-DOPE, through the quinone methide intermediate. DOPAC-quinone and DOMA-quinone degraded immediately with decarboxylation of the ortho-quinone intermediates to form 3,4-dihydroxybenzylalcohol (DHBAlc) and 3,4-dihydroxybenzaldehyde (DHBAld), respectively. DHBAlc-quinone was converted to DHBAld with a half-life of 9 min, while DHBAld-quinone degraded rapidly with a half-life of 3 min. This study confirmed the fact that ortho-quinones from DOPE, DOPEG, DOPAC and DOMA are converted to quinone methide tautomers as common intermediates, through proton rearrangement or decarboxylation. The unstable quinone methides afford stable alcoholic or carbonyl products.
Ito, Shosuke,Yamanaka, Yuta,Ojika, Makoto,Wakamatsu, Kazumasa
(2016/02/05)

Conversion of Simple Cyclohexanones into Catechols
A novel I2-catalyzed direct conversion of cyclohexanones to substituted catechols under mild and simple conditions has been described. This novel transformation is remarkable with the multiple oxygenation and dehydrogenative aromatization processes enabled just by using DMSO as the solvent, oxidant, and oxygen source. This metal-free and simple system demonstrates a versatile protocol for the synthesis of highly valuable substituted catechols and therefore streamlines the synthesis and modification of biologically important molecules for drug discovery.
Liang, Yu-Feng,Li, Xinyao,Wang, Xiaoyang,Zou, Miancheng,Tang, Conghui,Liang, Yujie,Song, Song,Jiao, Ning
supporting information
p. 12271 - 12277
(2016/09/28)

Exploring the synthetic applicability of a new carboxylic acid reductase from Segniliparus rotundus DSM 44985
A new carboxylic acid reductase (CAR) gene from Segniliparus rotundus DSM 44985 was overexpressed in Escherichia coli. The recombinant enzyme exhibited high activity toward a variety of aromatic and aliphatic carboxylic acids. Especially, it effectively reduced 4-hydroxybenzoic acid (8a) and 4-nitrobenzoic acid (19a), toward which the known Nocardia CAR exhibited no or little activity. The recombinant E. coli cells co-expressing the Segniliparus CAR and Nocardia PPTase genes catalyzed the reductions of vanillic acid (20a) and 3,4-dihydroxyphenylacetic acid (25a) to give vanillyl alcohol (20c) and 3-hydroxytyrosol (25c) with high yield, respectively. The endogenous aldehyde reductases of E. coli should be responsible for the further reduction of the produced aldehydes. These results demonstrated that Segniliparus CAR was a useful addition to the biocatalyst tool-box for the reduction of carboxylic acids and might find applications in the synthesis of valuable bio-based chemicals from renewable resources.
Duan, Yitao,Yao, Peiyuan,Chen, Xi,Liu, Xiangtao,Zhang, Rui,Feng, Jinhui,Wu, Qiaqing,Zhu, Dunming
p. 1 - 7
(2015/02/19)

AMPHIPATHIC AND OTHER DOUBLE-SIDED ALPHA-HELIX MIMETICS BASED ON A 1,2-DIPHENYLACETYLENE SCAFFOLD
Small-molecule scaffolds based on 1,2-diphenylacetylene that accurately replicate the spatial and angular projections of several side chains on both faces of an α-helix, specifically the i and i+7 side chains on one face, and the i and i+2 side chains on the other. The amphipathic α-helix mimetic can be used to disrupt disease-promoting protein-protein interactions that are mediated by α-helices.
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(2014/09/29)

Synthesis and antitumor activity of feruloyl and caffeoyl derivatives This paper is dedicated to Prof. Wei-xiao Hu for his lifelong commitment to mentoring graduate students
We developed two efficient protocols for the synthesis of feruloyl and caffeoyl derivatives from commercial vanillin and veratraldehyde. Pharmacological activities were assessed against a panel of human cancer cell lines in vitro. Most synthesized compounds demonstrated attractive cytotoxicity. Several new compounds demonstrated significant antiproliferative and cytotoxic activities against HeLa and Bewo tumor cell lines. In particular, 5-nitro caffeic adamantyl ester showed broad spectrum of tumor inhibition in 10 cell lines, and reduced tumor weight by 36.7% in vivo when administered at a dose of 40 mg kg-1.
Chen, Hui-Zhen,Chen, You-Bao,Lv, Ya-Ping,Zeng, Fang,Zhang, Juan,Zhou, Yong-Lie,Li, Han-Bing,Chen, Li-Fei,Zhou, Bin-Jie,Gao, Jian-Rong,Xia, Chun-Nian
p. 4367 - 4371
(2015/02/06)

NEUROPROTECTIVE AGENTS FOR TREATMENT OF NEURODEGENERATIVE DISEASES
A compound having formula I is useful for treating a neurodegenerative disease: I, R1 is an C1-12 organyl group; is a C1-12 heterocyclic ring system containing 5 to 12 ring atoms and up to three heteroatoms individually selected from the group consisting of N, O, S, and Se; R2 are C1-12 organyl groups; R7, R8 are each independently, hydrogen (H), hydroxyl, oxo (i.e., carbonyl), C1-8 alkyl, C1-8 alkoxyl, C2-8 alkenyl, C2-10 alkynyl, C5-7 cycloalkyl, C5-7 cycloalkenyl, halo, C1-4 aldehyde, or -NR4q where R4 is H, C1-8 alkyl, C2-8 alkenyl, C4-8 cycloalkyl, C4-8 cycloalkenyl, or C6-10 aryl; o is 0, 1, 2, 3, or 4; A is a C6-12 aryl group, C5-12 heteroaryl group, or an optionally substituted 3-hydroxypyridin- 4(1H)-one; p is an integer from 1 to 6; and Zm is absent or a divalent linking moiety; and m is an integer representing the number of time Z is repeated.
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Paragraph 000129

(2014/06/23)

Structure-activity relationship for (+)-taxifolin isolated from silymarin as an inhibitor of amyloid β aggregation
Silymarin, the seed extract of Silybium marianum, has preventive effects against Alzheimer's disease-like pathogenesis in vivo. We isolated (+)-taxifolin (4) from silymarin as an inhibitor of aggregation of the 42- residue amyloid -protein. Structure-activity relationship studies revealed the 30,40-dihydroxyl groups to be critical to the anti-aggregative ability, whereas the 7-hydroxyl group and the stereochemistry at positions 2 and 3 were not important.
Sato, Mizuho,Murakami, Kazuma,Uno, Mayumi,Ikubo, Haruko,Nakagawa, Yu,Katayama, Sumie,Akagi, Ken-Ichi,Irie, Kazuhiro
p. 1100 - 1103
(2013/07/27)

Preliminary antiproliferative evaluation of natural, synthetic benzaldehydes and benzyl alcohols
Vanillin, o-vanillin, natural and synthetic benzaldehydes and benzyl alcohols were assessed for antiproliferative effects using different human cell lines. Benzyl alcohols were synthesized from benzaldehydes reduced with NaBH4 in methanol solution. A new method for deprotection of ether compounds with TiCl4 solution was achieved with better performance, than previously reported. Twenty four compounds were tested. The in vitro growth inhibition assay was based on sulphorhodamine dye to quantify cell viability. Catechol 9 derived from piperonal as well as compounds 4 and 12 showed higher cytotoxicity on breast and prostate cancer cell lines (MDA-MB-231 and PC-3 respectively). o-Vanillin 5 has the highest cytotoxicity for all cell lines. IC50 values of 35.40 ± 4.2 ?M Breast MDA-MB231; 47.10 ± 3.8 ?M Prostate PC-3; 72.50 + 5.4 ?M Prostate DU-145; 85.10 + 6.5 ?M and Colon HT-29, were obtained without toxicity towards dermal human fibroblast (DHF cells).
Madrid, Alejandro,Espinoza, Luis,Catalan, Karen,Gonzalez, Cesar,Montenegro, Ivan,Mellado, Marco,Werner, Enrique,Cuellar, Mauricio,Villena, Joan
p. 1814 - 1816
(2014/03/21)

Ferrocene tagged functional polymer: A robust solid-phase reagent for O-demethylation
Ferrocene tagged functional polymer was synthesized by exploiting the propensity of the Merrifield resin to undergo quaternization with N-ferrocenylmethyl benzimidazole followed by subsequent anion metathesis reaction. The synthesized polymer when employed as a solid-phase reagent for O-demethylation of aryl methyl ethers, showed TON in the range of 7373-8930 and TOF in the range of 279-494 h-1.
Kurane, Rajanikant,Gaikwad, Vipul,Jadhav, Jagannath,Salunkhe, Rajashri,Rashinkar, Gajanan
p. 6361 - 6366,6
(2012/12/12)

Hydroxylation of p-substituted phenols by tyrosinase: Further insight into the mechanism of tyrosinase activity
A study of the monophenolase activity of tyrosinase by measuring the steady state rate with a group of p-substituted monophenols provides the following kinetic information: kcatm and the Michaelis constant, KMm. Analysis of these data taking into account chemical shifts of the carbon atom supporting the hydroxyl group (δ) and σp+, enables a mechanism to be proposed for the transformation of monophenols into o-diphenols, in which the first step is a nucleophilic attack on the copper atom on the form Eox (attack of the oxygen of the hydroxyl group of C-1 on the copper atom) followed by an electrophilic attack (attack of the hydroperoxide group on the ortho position with respect to the hydroxyl group of the benzene ring, electrophilic aromatic substitution with a reaction constant ρ of -1.75). These steps show the same dependency on the electronic effect of the substituent groups in C-4. Furthermore, a study of a solvent deuterium isotope effect on the oxidation of monophenols by tyrosinase points to an appreciable isotopic effect. In a proton inventory study with a series of p-substituted phenols, the representation of kcatfn/kcatf0 against n (atom fractions of deuterium), where kcatfn is the catalytic constant for a molar fraction of deuterium (n) and kcatf0 is the corresponding kinetic parameter in a water solution, was linear for all substrates. These results indicate that only one of the proton transfer processes from the hydroxyl groups involved the catalytic cycle is responsible for the isotope effects. We suggest that this step is the proton transfer from the hydroxyl group of C-1 to the peroxide of the oxytyrosinase form (Eox). After the nucleophilic attack, the incorporation of the oxygen in the benzene ring occurs by means of an electrophilic aromatic substitution mechanism in which there is no isotopic effect.
Munoz-Munoz, Jose Luis,Berna, Jose,Garcia-Molina, Maria del Mar,Garcia-Molina, Francisco,Garcia-Ruiz, Pedro Antonio,Varon, Ramon,Rodriguez-Lopez, Jose N.,Garcia-Canovas, Francisco
scheme or table
p. 228 - 233
(2012/10/18)

Chemical conversions of salvianolic acid B by decoction in aqueous solution
Salvianolic acid B (Sal B) is the most abundant phenolic compound in Salvia miltiorrhiza, which has been widely used for the treatment of cardiovascular diseases in Oriental medicine. To elucidate structure of the converted compounds of Sal B by decoction
Lee, Hyoung Jae,Cho, Jeong-Yong,Moon, Jae-Hak
p. 1196 - 1204,9
(2020/07/31)

Feruloylacetone as the model compound of half-curcumin: Synthesis and antioxidant properties
In order to clarify the contribution of phenolic and enolic hydroxyl group to the antioxidant capacity of feruloylacetone, a model compound of half-curcumin, 6-(p-hydroxy-m-methoxyphenyl)-5-hexene-2,4-dione (FT), 6-(p-benzyloxy-m-methoxyphenyl)-5-hexene-2,4-dione (BMFT), 6-(m,p- dihydroxyphenyl)-5-hexene-2,4-dione (DDFT), 6-(p-hydroxy-m-methoxyphenyl)hexane- 2,4-dione (DHFT), 6-(p-hydroxy-m-methoxyphenyl)-5-hexene-2,4-diol (THFT), and ethyl 2-(p-hydroxy-m-methoxybenzylidene)-3-oxobutanoate (EOFT) were synthesized. The radical-scavenging abilities of these compounds were tested by trapping 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS+), 2,2′-diphenyl-1-picrylhydrazyl (DPPH), and galvinoxyl radicals. The reductive capacities were screened by quenching singlet oxygen and by inhibiting the oxidation of linoleic acid. They were also employed to inhibit the oxidation of DNA mediated by hydroxyl radical and 2,2′-azobis(2-amidinopropane hydrochloride) (AAPH). In addition, they were applied to protect erythrocytes against AAPH- and hemin-induced hemolysis. The obtained results revealed that the antioxidant capacity of half-curcumin was derived from the phenolic-OH and the conjugated linkage between phenolic and enolic-OH. The enolic-OH itself cannot trap radicals.
Feng, Jian-Ying,Liu, Zai-Qun
scheme or table
p. 1198 - 1206
(2011/04/22)

Synthesis of catechols from phenols via Pd-catalyzed silanol-directed C-H oxygenation
A silanol-directed, Pd-catalyzed C-H oxygenation of phenols into catechols is presented. This method is highly site selective and general, as it allows for oxygenation of not only electron-neutral but also electron-poor phenols. This method operates via a silanol-directed acetoxylation, followed by a subsequent acid-catalyzed cyclization reaction into a cyclic silicon-protected catechol. A routine desilylation of the silacyle with TBAF uncovers the catechol product.
Huang, Chunhui,Ghavtadze, Nugzar,Chattopadhyay, Buddhadeb,Gevorgyan, Vladimir
supporting information; experimental part
p. 17630 - 17633
(2011/12/16)

Bisdemethylcurcumin and structurally related hispolon analogues of curcumin exhibit enhanced prooxidant, anti-proliferative and anti-inflammatory activities in vitro
Curcumin, a component of turmeric (Curcuma longa), exhibits anti-inflammatory and anti-proliferative activities through the generation of reactive oxygen species (ROS). Curcumin (diferuloylmethane) contains two hydroxyl, two methoxy and two phenyl groups but how these groups contribute to its activity is poorly understood. We synthesized analogues that varied in inclusion of these groups and compared their activity. We found that bisdemethylcurcumin (BDC) was more potent than curcumin as an anti-inflammatory agent as indicated by suppression of TNF-induced NF-κB activation, more potent as an anti-proliferative agent, and more potent in inducing ROS. Hispolon, which lacks one aromatic unit in relation to curcumin, also exhibited enhanced anti-inflammatory and anti-proliferative activities. When synthetic curcumin (Cur-S) was compared with bisdemethylcurcumin (BDC), hispolon, hispolon methyl ether (HME), dehydroxy hispolon (DH), hydroxy hispolon (HH), methoxy hispolon methyl ether (MHME), and methoxy hispolon (MH), we found that following order of anti-inflammatory activity: BDC=Hispolon>HME>HH>Cur-S>MHME>MH>DH; for anti-proliferative: Hispolon>BDC>MHME>Cur-S>MH>HME=HH>DH; and for prooxidant: BDC>Cur-S=MHME>HH>MH+HME>DH (254-1414 mean fluorescence intensity). Thus, dehydroxy hispolon was least potent for all three activities. Overall the results indicate that the substitution of a hydroxyl group for a methoxy group at the meta positions of the phenyl rings in curcumin significantly enhanced the anti-inflammatory activity, and the removal of phenyl ring at the 7th position of the heptadiene back bone and addition of hydroxyl group significantly increased the anti-proliferative activity of curcumin.
Ravindran, Jayaraj,Subbaraju, Gottumukkala V.,Ramani, Modukuri V.,Sung, Bokyung,Aggarwal, Bharat B.
experimental part
p. 1658 - 1666
(2011/11/29)

Formation of nitric oxide, ethyl nitrite and an oxathiolone derivative of caffeic acid in a mixture of saliva and white wine
Reactions of salivary nitrite with components of wine were studied using an acidic mixture of saliva and wine. The formation of nitric oxide (NO) in the stomach after drinking wine was observed. The formation of NO was also observed in the mixture (pH 3.6) of saliva and wine, which was prepared by washing the oral cavity with wine. A part of the NO formation in the stomach and the oral cavity was due to the reduction of salivary nitrite by caffeic and ferulic acids present in wine. Ethyl nitrite produced by the reaction of salivary nitrite and ethyl alcohol in wine also contributed to the formation of NO. In addition to the above reactions, caffeic acid in wine could be transformed to the oxathiolone derivative, which might have pharmacological functions. The results obtained in this study may help in understanding the effects of drinking wine on human health.
Takahama, Umeo,Tanaka, Mariko,Hirota, Sachiko
body text
p. 293 - 303
(2011/10/09)

Hypervalent iodine-mediated oxygenative phenol dearomatization reactions
Both λ3- and λ5-iodanes have proven to be useful reagents in the oxygenative dearomatization of phenols, and exploitations of their chemistry in the conception of both substrate- and reagent-controlled asymmetric variants of such a transformation of great value for natural product synthesis have shown evident signs of success. Moreover, the use of stabilized IBX (i.e., SIBX) in our methodology for O-demethylation of 2-methoxyphenols, which relies on the same key oxygenating dearomatization event, is reported here to be much more efficacious than that of IBX itself in the chemoselective one-step conversion of homovanillyl alcohol into hydroxytyrosol, and bergenin into norbergenin.
Pouységu, Laurent,Sylla, Tahiri,Garnier, Tony,Rojas, Luis B.,Charris, Jaime,Deffieux, Denis,Quideau, Stéphane
experimental part
p. 5908 - 5917
(2010/09/09)

Phenolic and enolic hydroxyl groups in curcumin: Which plays the major role in scavenging radicals?
The aim of this work is to clarify the antioxidant abilities of phenolic and enolic hydroxyl groups in curcumin. 1,7-Bis(4-benzyloxy-3-methoxyphenyl)-1, 6-heptadiene-3,5-dione (BEC), 1,7-bis(4-hydroxy-3-methoxyphenyl)heptane-3,5-diol (OHC), 1,7-bis(4-hydroxy-3-methoxyphenyl)heptane-3,5-dlone (THC), and 1,7-bis(3,4-dihydroxyphenyl)-1,6-heptadiene-3,5-dione (BDC) are synthesized to determine the antioxidant activities by using antiradical assays against 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical, galvinoxyl radical, and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) cation radical (ABTS?+) and by protecting DNA and erythrocyte against 2,2′-azobis(2-amidinopropane hydrochloride) (AAPH) induced oxidation. The phenolic hydroxyl is the main group for curcumin to trap DPPH, galvinoxyl, and ABTS?+ radicals. The conjugative system between enolic and phenolic hydroxyl groups is beneficial for curcumin to protect erythrocytes against hemin-induced hemolysis and to protect DNA against AAPH-lnduced oxidation, but is not beneficial for curcumin to protect erythrocytes against AAPH-induced hemolysis. More hydroxyl groups enhance the antioxidant effectiveness of curcumin in the experimentel systems employed herein. Therefore, curcumin acts as an antioxidant through the phenolic hydroxyl group.
Feng, Jian-Ying,Liu, Zai-Qun
scheme or table
p. 11041 - 11046
(2010/09/04)