- (1,5)-Acetyl Shifts in Cycloadducts derived from 2-Acetyl-1,4-benzoquinones
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(1,5)-Acetyl shifts have been investigated in a number of cycloadducts prepared from 2-acetyl-1,4-benzoquinone and dienes, and it has been shown that the direction of migration depends on the nature of the diene substituents.
- Cooper, Simon C.,Sammes, Peter G.
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- Synthesis and pharmacological evaluation of acylhydroquinone derivatives as potent antiplatelet agents
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Platelets are the smallest blood cells, and their activation (platelet cohesion or aggregation) at sites of vascular injury is essential for thrombus formation. Since the use of antiplatelet therapy is an unsolved problem, there are now focused and innovative efforts to develop novel antiplatelet compounds. In this context, we assessed the antiplatelet effect of an acylhydroquinone series, synthesized by Fries rearrangement under microwave irradiation, evaluating the effect of diverse acyl chain lengths, their chlorinated derivatives, and their dimethylated derivatives both in the aromatic ring and also the effect of the introduction of a bromine atom at the terminus of the acyl chain. Findings from a primary screening of cytotoxic activity on platelets by lactate dehydrogenase assay identified 19 non-toxic compounds from the 27 acylhydroquinones evaluated. A large number of them showed IC50 values less than 10 μM acting against specific pathways of platelet aggregation. The highest activity was obtained with compound 38, it exhibited sub-micromolar IC50 of 0.98 ± 0.40, 1.10 ± 0.26, 3.98 ± 0.46, 6.79 ± 3.02 and 42.01 ± 3.48 μM against convulxin-, collagen-, TRAP-6-, PMA- and arachidonic acid-induced platelet aggregation, respectively. It also inhibited P-selectin and granulophysin expression. We demonstrated that the antiplatelet mechanism of compound 38 was through a decrease in a central target in human platelet activation as in mitochondrial function, and this could modulate a lower response of platelets to activating agonists. The results of this study show that the chemical space around ortho-carbonyl hydroquinone moiety is a rich source of biologically active compounds, signaling that the acylhydroquinone scaffold has a promising role in antiplatelet drug research.
- Méndez, Diego,Donoso-Bustamante, Viviana,Pablo Millas-Vargas, Juan,Pessoa-Mahana, Hernán,Araya-Maturana, Ramiro,Fuentes, Eduardo
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- A chromone derivative as a colorimetric and “ON-OFF-ON” fluorescent probe for highly sensitive and selective detection of Cu2+ and S2?
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A chromone derivative (L) which could be utilized for reversibly detecting Cu2+ and S2? by means of fluorescence quenching and displacement in aqueous solution was designed and developed. Upon the addition of Cu2+, the strong blue-green fluorescence emission of L was quenched rapidly and then recovered in 1 min by successively adding S2?. Furthermore, with the alternate addition of Cu2+ and S2?, the reversible cycles could be repeated for at least four times, which meant that L could be identified as a renewable dual-functioning probe. What's more, due to its excellent sensing performances, this probe L could also be used to detect Cu2+ and S2? with test strips conveniently.
- Liu, Cong,Tian, Limei,Liu, Kui,Xue, Jia,Fan, Long,Li, Tianrong,Yang, Zheng-yin
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- Iron-catalyzed arene C-H hydroxylation
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The sustainable, undirected, and selective catalytic hydroxylation of arenes remains an ongoing research challenge because of the relative inertness of aryl carbon-hydrogen bonds, the higher reactivity of the phenolic products leading to over-oxidized by-products, and the frequently insufficient regioselectivity. We report that iron coordinated by a bioinspired L-cystine-derived ligand can catalyze undirected arene carbon-hydrogen hydroxylation with hydrogen peroxide as the terminal oxidant. The reaction is distinguished by its broad substrate scope, excellent selectivity, and good yields, and it showcases compatibility with oxidation-sensitive functional groups, such as alcohols, polyphenols, aldehydes, and even a boronic acid. This method is well suited for the synthesis of polyphenols through multiple carbon-hydrogen hydroxylations, as well as the late-stage functionalization of natural products and drug molecules.
- Cheng, Lu,Wang, Huihui,Cai, Hengrui,Zhang, Jie,Gong, Xu,Han, Wei
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- Synthesis and evaluation of trypanocidal activity of chromane-type compounds and acetophenones
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American trypanosomiasis (Chagas disease) caused by the Trypanosoma cruzi parasite, is a severe health problem in different regions of Latin America and is currently reported to be spreading to Europe, North America, Japan, and Australia, due to the migration of populations from South and Central America. At present, there is no vaccine available and chemotherapeutic options are reduced to nifurtimox and benznidazole. Therefore, the discovery of new molecules is urgently needed to initiate the drug development process. Some acetophenones and chalcones, as well as chromane-type substances, such as chromones and flavones, are natural products that have been studied as trypanocides, but the relationships between structure and activity are not yet fully understood. In this work, 26 compounds were synthesized to determine the effect of hydroxyl and isoprenyl substituents on trypanocide activity. One of the compounds showed interesting activity against a resistant strain of T. cruzi, with a half effective concentration of 18.3 μM ± 1.1 and an index of selectivity > 10.9.
- Escobar, Gustavo,González, Luis A.,Qui?ones, Wiston,Robledo, Sara,Upegui, Yulieth
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- Bisketene Equivalents as Diels-Alder Dienes
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2,5-Bis(tert-butyldimethylsilyloxy)furans are established as vicinal bisketene equivalents for application as dienes in the Diels-Alder reaction. Cycloaddition with olefinic dienophiles, under exceptionally mild conditions, enables convergent access to highly substituted para-hydroquinones in unprotected form via a one-pot Diels-Alder/ring-opening/tautomerization sequence. The synthesis of para-benzoquinones from acetylenic dienophiles, including benzynes, is also demonstrated, and 2,5-bis(tert-butyldimethylsilyloxy)pyrroles are established as competent dienes for the synthesis of para-iminoquinones. Application in natural product synthesis enables gram-scale access to the neuroprotective agent (±)-indanostatin.
- Dissanayake, Isuru,Hart, Jacob D.,Becroft, Emma C.,Sumby, Christopher J.,Newton, Christopher G.
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supporting information
p. 13328 - 13333
(2020/09/03)
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- Assessing parameter suitability for the strength evaluation of intramolecular resonance assisted hydrogen bonding in O-carbonyl hydroquinones
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Intramolecular hydrogen bond (IMHB) interactions have attracted considerable attention due to their central role in molecular structure, chemical reactivity, and interactions of biologically active molecules. Precise correlations of the strength of IMHB’s with experimental parameters are a key goal in order to model compounds for drug discovery. In this work, we carry out an experimental (NMR) and theoretical (DFT) study of the IMHB in a series of structurally similar o-carbonyl hydroquinones. Geometrical parameters, as well as Natural Bond Orbital (NBO) and Quantum Theory of Atoms in Molecules (QTAIM) parameters for IMHB were compared with experimental NMR data. Three DFT functionals were employed to calculated theoretical parameters: B3LYP, M06-2X, and ωB97XD. O . . . H distance is the most suitable geometrical parameter to distinguish among similar IMHBs. Second order stabilization energies ?Eij(2) from NBO analysis and hydrogen bond energy (EHB) obtained from QTAIM analysis also properly distinguishes the order in strength of the studied IMHB. ?Eij(2) from NBO give values for the IMHB below 30 kcal/mol, while EHB from QTAIM analysis give values above 30 kcal/mol. In all cases, the calculated parameters using ωB97XD give the best correlations with experimental1H-NMR chemical shifts for the IMHB, with R2 values around 0.89. Although the results show that these parameters correctly reflect the strength of the IMHB, when the weakest one is removed from the analysis, arguing experimental considerations, correlations improve significantly to values around 0.95 for R2
- Martínez-Cifuentes, Maximiliano,Monroy-Cárdenas, Matías,Millas-Vargas, Juan Pablo,Weiss-López, Boris E.,Araya-Maturana, Ramiro
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- A novel chromone derivative as dual probe for selective sensing of Al(III) by fluorescent and Cu(II) by colorimetric methods in aqueous solution
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Based on the chromone skeleton, a simple and novel probe that is 6-ethoxychromone-3-carbaldehyde-(furanyl) hydrazone (L) has been synthesized and completely characterized. It exhibited representative turn-on fluorescent properties and obviously colorimetric changes with high selectivity to Al3+ and Cu2+. For Al3+, L displayed a turn on green fluorescence in EtOH/H2O (3/2) aqueous media over other common cations. With Cu2+, L perceived Cu2+ through the naked-eye by the color changed-from colorless to yellow. Moreover, the coordination ratio between L-Al3+and L-Cu2+ was 1:1 which could be verified by the Job's plot, 1H NMR and high-resolution mass spectrum. Consequentially, L could be used as a solid probe for both Al3+ and Cu2+.
- Tian, Limei,Xue, Jia,Li, Si-liang,Yang, Zheng-yin
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- Half-wave potentials and in vitro cytotoxic evaluation of 3-acylated 2,5-bis(phenylamino)-1,4-benzoquinones on cancer cells
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A broad range of 3-acyl-2,5-bis(phenylamino)-1,4-benzoquinones were synthesized and their voltammetric values, as well as in vitro cancer cell cytotoxicities, were assessed. The members of this series were prepared from acylbenzoquinones and phenylamines, in moderate to good yields (47-74%), through a procedure involving a sequence of two in situ regioselective oxidative amination reactions. The cyclic voltammograms of the aminoquinones exhibit two one-electron reduction waves to the corresponding radical-anion and dianion, and two quasi-reversible oxidation peaks. The first and second half-wave potential values (E1/2) of the members of the series were sensitive to the push-pull electronic effects of the substituents around the benzoquinone nucleus. The in vitro cytotoxic activities of the 3-acyl-2,5-bis(phenylamino)-1,4-benzoquinones against human cancer cells (bladder and prostate) and non-tumor human embryonic kidney cells were measured using the MTT colorimetric method. The substitution of both aniline groups, by either methoxy (electron donating effect) or fluorine (electron withdrawal effect), decreased the cytotoxicity in the aminoquinones. Among the members of the unsubstituted phenylamino series, two of the 18 compounds showed interesting anti-cancer activities. A preliminary assay, looking for changes in the expression of selected genes, was performed. In this context, the two compounds increased TNF gene expression, suggesting an association with an inflammatory-like response.
- Benites, Julio,Valderrama, Jaime A.,Ramos, Maryan,Valenzuela, Maudy,Guerrero-Castilla, Angélica,Muccioli, Giulio G.,Calderon, Pedro Buc
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- Practical and efficient synthesis of hydroxyaryl ketones catalyzed by HF@SiO2 under solvent-free condition
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A wide variety of hydroxyaryl ketones bearing different motifs was successfully synthesized with good yields and excellent selectivities in the presence of HF@SiO2 as an environmental friendly acid under solvent-free condition. Mild and green reaction conditions and excellent yields (50-91%) make this method an attractive method for the efficient synthesis of hydroxyaryl ketones. Fries rearrangement of phenyl benzoate in the presence of HF@SiO2 led to p-hydroxybenzophenone, while phenyl acetate in the same conditions produced o-hydroxyacetophenone as a single isomer.
- Paghandeh, Hossein,Saeidian, Hamid,Ghaffarzadeh, Mohammad
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p. 809 - 814
(2018/09/26)
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- A new off-on fluorescent sensor for the detection of Al(III) based on a chromone-derived Schiff-base
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A new Al3+ sensor, 6-ethoxychromone-3-carbaldehyde-(3-hydroxy-2-naphthalene acyl) hydrazone (L), was designed and synthesized. The sensor L could exist steadily and detect Al3+ in the pH range from 5.0 to 8.0 in ethanol and water (3:1, v/v). This sensor showed good selectivity and high sensitivity towards Al3+ in the presence of most metal ions, and a remarkable enhancement in fluorescence emission intensity at 508 nm (λex = 420 nm) was observed with addition of 1equiv Al3+, which was attributed to the inhibition of photoinduced electron-transfer (PET) phenomenon and C[dbnd]N isomerization process. With the fluorescence titration experiments and the ESI-MS spectrum data, we reached the conclusion that the binding ratio between L and Al3+ was 2:1. Besides, the binding constant (Ka) between L and Al3+ was calculated to be 9.24 × 103 M?1 and the detection limit of L for Al3+ was as low as 1.82 × 10?7 M.
- Liu, Li-mei,Yang, Zheng-yin
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p. 588 - 592
(2017/10/25)
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- A novel chromone and rhodamine derivative as fluorescent probe for the detection of Zn(II) and Al(III) based on two different mechanisms
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In this study, a novel fluorescent probe, 6?hydroxychromone?3?carbaldehyde?(rhodamine B carbonyl) hydrazine (L), for Zn2+ and Al3+ was designed and synthesized. Initially, this probe L exhibited inferior fluorescence emission peak centered at 488 nm in EtOH/HEPES solution (3/1, 10.0 μM HEPES, pH 7.4) when excited at 421 nm. After the addition of Zn2+, this probe L displayed excellent selectivity towards Zn2+ with obvious fluorescence color change from colorless to yellow, which might be attributed to the formation of a 1:1 ligand-metal complex resulting in the inhibition of photo-induced electron transfer phenomenon. Whereas, the prepared Zn2+ complex of L could be used as a ratiometric fluorescent probe to detect Al3+ on the basis of fluorescence resonance energy transfer mechanism. This ligand-metal complex of Zn2+ (LZn) showed high selectivity towards Al3+ with obvious enhancement in fluorescence emission intensity at 580 nm and remarkable decrease in fluorescence emission intensity at 488 nm, and the fluorescence color also changed from yellow to pink. Furthermore, the detection limit of the probe L, LZn towards Zn2+, Al3+ were 1.25 × 10?7 M and 3.179 × 10?6 M, respectively. Additionally, the complexation properties of L towards Zn2+ and LZn towards Al3+ were studied in detail.
- Pang, Bing-jie,Li, Chao-rui,Yang, Zheng-yin
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p. 641 - 647
(2018/07/13)
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- Design, synthesis and docking study of pyridine and thieno[2,3-b] pyridine derivatives as anticancer PIM-1 kinase inhibitors
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A series of pyridine and thieno[2,3-b]pyridine derivatives have been designed and synthesized as anticancer PIM-1 kinase inhibitors. Thirty-seven compounds were selected by NCI to be tested initially at a single dose (10 μM) in the full NCI 60 cell line panel. Compound 5b showed potent anticancer activity and was tested twice in the five-dose assay which confirmed its potent antitumor activity (GI50 values 0.302–3.57 μM) against all tested tumor cell lines except six cell lines where they showed moderate sensitivity. This compound was sent to NCI biological evaluation committee and still under consideration for further testing. In addition, the most active anticancer compounds in each series, 5b, 8d, 10c, 13h, and 15e, were evaluated for their PIM-1 kinase inhibitory activity. Compound 8d was the most potent one with IC50 = 0.019 μM followed by 5b, 15e, 10c and 13h with IC50 values 0.044, 0.083, 0.128 and 0.479 μM respectively. Moreover, docking study of the most active compounds in PIM-1 kinase active site was consistent with the in vitro activity.
- Abdelaziz, Marwa E.,El-Miligy, Mostafa M.M.,Fahmy, Salwa M.,Mahran, Mona A.,Hazzaa, Aly A.
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p. 674 - 692
(2018/08/02)
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- A hydroquinone derivatives of synthetic method (by machine translation)
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The invention discloses a hydroquinone derivatives 2, 5 - dihydroxy hydroquinone synthetic method, in order to hydroquinone as the starting material, after the acylation, rearrangement, a Friedel-crafts reaction to obtain the target compound, this compound is an important intermediate synthesis of natural pigment. (by machine translation)
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Paragraph 0027; 0028
(2017/07/19)
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- A Chromone-Derived Schiff-Base Ligand as Al3+ "turn on" Fluorescent Sensor: Synthesis and Spectroscopic Properties
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In this study, a novel chromone-derived Schiff-base ligand called 6-Hydroxy-3-formylchromone (2′-furan formyl) hydrazone (HCFH) has been designed and synthesized as a "turn on" fluorescent sensor for Al3+. This sensor HCFH showed high selectivity and sensitivity towards Al3+ over other metal ions investigated, and most metal ions had nearly no influences on the fluorescence response of HCFH to Al3+. Additionally, the significant enhancement by about 171-fold in fluorescence emission intensity at 502 nm was observed in the presence of Al3+ in ethanol, and it was due to the chelation-enhanced fluorescence (CHEF) effect upon complexation of HCFH with Al3+ which inhibited the photoinduced electron transfer (PET) phenomenon from the Schiff-base nitrogen atom to chromone group. Moreover, this sensor formed a 1: 1 complex with Al3+ and the fluorescence response of HCFH to Al3+ was nearly completed within 1 min. Thus, this sensor HCFH could be used to detect and recognize Al3+ for real-time detection.
- Li, Chao-Rui,Qin, Jing-Can,Wang, Bao-Dui,Fan, Long,Yan, Jun,Yang, Zheng-Yin
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p. 345 - 353
(2016/01/15)
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- A chromone-derived Schiff-base as Al3+“turn-on” fluorescent probe based on photoinduced electron-transfer (PET) and C[dbnd]N isomerization
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In this study, a novel chromone-derived Schiff-base ligand which was called bis(6-hydroxychromone-3-methylidene)-o-phenylenediimine (1) was designed, synthesized, and evaluated as an Al3+“turn on” fluorescent probe. This probe 1 showed good selectivity and high sensitivity towards Al3+in the presence of most metal ions, and a remarkable enhancement by about 30.91-fold in fluorescence emission intensity at 459?nm was observed with addition of 1?equiv of Al3+, which was attributed to the inhibition of photoinduced electron-transfer (PET) phenomenon and C[dbnd]N isomerization process at the excited state. Moreover, the fluorescence response of 1 to Al3+was nearly completed within 10?min. Thus, this probe 1 could be utilized for sensing and monitoring Al3+in environmental and biological systems for real-time detection.
- Li, Chao-rui,Li, Si-liang,Yang, Zheng-yin
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p. 4898 - 4904
(2016/10/22)
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- P-Benzoquinone adsorption-separation, sensing and its photoinduced transformation within a robust Cd(II)-MOF in a SC-SC fashion
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p-Benzoquinone (Q) adsorption-separation, sensing and its photoinduced transformation within a robust Cd(ii)-MOF (1) is reported. All the adsorption, sensing and photochemical reactions are directly performed on the single-crystals of 1. This journal is
- Yang, Fan,Liu, Qi-Kui,Wu, Dan,Li, An-Yan,Dong, Yu-Bin
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supporting information
p. 7443 - 7446
(2015/05/04)
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- Design, synthesis and docking studies of novel thienopyrimidine derivatives bearing chromone moiety as mTOR/PI3Kα inhibitors
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Two series of thienopyrimidine derivatives (10a-k, 16a-j) bearing chromone moiety were designed and synthesized. All the compounds were evaluated for inhibitory activity against mTOR kinase at a concentration of 10uM. Four selected compounds were further evaluated for the IC50 values against mTOR kinase, PI3Kα kinase and two cancer cell lines. Some of the target compounds exhibited moderate to excellent mTOR/PI3Kα kinase inhibitory activity and cytotoxicity. The most promising compound 16i showed good inhibitory activity against mTOR/PI3Kα kinase and good antitumor potency for H460 and PC-3 cell lines with IC50 values of 0.16 ± 0.03 μM, 2.35 ± 0.19 μM, 1.20 ± 0.23 μM and 0.85 ± 0.04 μM, which were 8.6, >5, 7.9 and 19.1 times more active than compound I (1.37 ± 0.07 μM, >10 μM, 9.52 ± 0.29 μM, 16.27 ± 0.54 μM), respectively. Structure-activity relationships (SARs) and docking studies indicated that the chromone moiety is necessary for the potent antitumor activity and cytotoxicity of these compounds. Substitution of the chromone moiety at the 6-position has a significant impact to the inhibitory activity, in particular a carboxylic acid group, produced the best potency.
- Zhu, Wufu,Chen, Chen,Sun, Chengyu,Xu, Shan,Wu, Chunjiang,Lei, Fei,Xia, Hui,Tu, Qidong,Zheng, Pengwu
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- Catalytic application of fluorous silica gel in Fries rearrangement
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Commercially available fluorous silica gel (Fluoro Flash) with no further post-modification was successfully investigated and applied merely as a catalyst in Fries rearrangement of various aryl esters under solvent free conditions in 4 h and optimized temperatures. In addition to good yields and recyclability of the catalyst, toxicity of reaction medium, by-products, and wastes were minimized. Also, low catalyst loading was another advantage of this methodology.
- Ghaffarzadeh, Mohammad,Ahmadi, Maryam
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- A novel synthesis of naringenin and related flavanones
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Efficient methods are reported for the preparation of naringenin (4',5,7-trihydroxyflavanone) which could be easily scaled-up. They have been applied to three other flavanones (6.hydroxyflavanone, 6,4'-dihydroxyflavanone, 6,3',4'-trihydroxyflavanone) suitably.
- Cui, Wei,Zhang, Ji,Wang, Qian,Gao, Kai,Zhang, Wei,Yang, Jian
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p. 686 - 689
(2015/02/19)
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- Design and syntheses of novel N′-((4-oxo-4H-chromen-3-yl)methylene) benzohydrazide as inhibitors of cyanobacterial fructose-1,6-/sedoheptulose-1,7- bisphosphatase
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Cyanobacterial fructose-1,6-/sedoheptulose-1,7-bisphoshatase (Cy-FBP/SBPase) is an important target enzyme for finding inhibitors to solve harmful algal bloom (HAB). In this study, as potential inhibitors of Cy-FBP/SBPase, a series of novel chromone-connecting benzohydrazone compounds (Novel N′-((4-oxo-4H-chromen-3-yl)methylene)benzohydrazide) were designed and synthesized. Their inhibitory activities against Cy-FBP/SBPase were further examined in vitro. Some of these compounds, such as f6-f8, f11, f12 and f16, exhibit higher inhibitory activities (IC50 = 11.2-16.1 μM), especially, the compound f7 was identified as the most potent inhibitor with IC50 value of 11.2 μM. The probable binding-mode of compound f7 was further analyzed carefully by molecular docking methods. These results indicate that compound f7 could be used as a lead compound for further optimization and might have potential to be developed as a new algicide.
- Tu, Qi-Dong,Li, Ding,Sun, Yao,Han, Xin-Ya,Yi, Fan,Sha, Yibamu,Ren, Yan-Liang,Ding, Ming-Wu,Feng, Ling-Ling,Wan, Jian
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p. 2826 - 2831
(2013/06/27)
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- Synthesis and biological evaluation of new flavonoid fatty acid esters with anti-adipogenic and enhancing glucose consumption activities
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Oleoyl Formononetin (OF) has good weight loss activity and hypolipidemic activity, could improve insulin sensitivity and suppress adipogenesis. To acquire better biological activities, three series of flavonoid fatty acid esters were designed and synthesized by optimizing the structure of OF. Their bioactivities were assayed in vitro. Some of these novel compounds could effectively inhibit preadipocyte proliferation and adipogenesis. Moreover, they could enhance glucose consumption in adipocytes notably.
- Zhao, Wei,Sun, Jie,Xiang, Hua,Zeng, Yan-Yan,Li, Xiao-Bo,Xiao, Hong,Chen, De-Ying,Ma, Ren-Ling
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experimental part
p. 3192 - 3203
(2011/06/24)
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- Synthesis of hydrazones schiff bases and microbiological evaluation of lsonicotinoyl hydrazide with different acetophenone
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A series of hydrazones Schiff bases compounds have been synthesized by reacting isonicotinoyl hydrazide with 2-hydroxy-5-chloro acetophenone, 2-hydroxy-5-methyl acetophenone, 2-hydroxy-5-carboxy acetophenone, 2,5-dihydroxy acetophenone, 2-hydroxy-5-chloro-4-methyl acetophenone, 2-hydroxy-5-chloro-3- nitro acetophenone, 2-hydroxy-5-methyl-3-nitro acetophenone and 2-hydroxy-5-bromo acetophenone. The Schiff bases have been evaluated for the antifungal and antibacterial activities.
- Kelode,Mandlik,Aswar
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scheme or table
p. 1053 - 1062
(2012/04/04)
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- Catalytic oxidations of enolizable ketones using 2-alkylidene-4- oxothiazolidine vinyl bromide
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Direct oxidation of enolizable ketones to α-hydroxy derivatives, vicinal dicarbonyls or tricarbonyl compounds has been achieved by a catalytic amount of 2-alkylidene-4-oxothiazolidine vinyl bromide in DMSO as a solvent. The yields range from moderate to good.
- Baranac-Stojanovi?, Marija,Markovi?, Rade,Stojanovi?, Milovan
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experimental part
p. 8000 - 8008
(2011/11/06)
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- Synthesis of novel flavone acyl esters and correlation of log P value with antioxidant and antimicrobial activity
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Three series of flavones namely 6-hydroxy flavone, 6-chloro-3-hydroxy flavone, 3,6-dihydroxy flavone were synthesized. They were further benzoylated with different aromatic acid chlorides in the presence of pyridine gave three of acyl esters series (SCF 1 to 8, SHF 1 to 8 and SDF 1 to 8). The yields of all the substituted flavones were found satisfactory. These compounds were purified, characterized by their spectral data. log P and pKa value. They were screened for in vitro radical (DPP?) scavenging activity, showed appreciable activity. 7 compounds showed antimicrobial activity against Gram-positive bacteria. Further, the MIC values of these 7 compounds were also determined. All the compounds showing antioxidant activity also showed antibacterial activity. The relationship between log P, antioxidant and antibacterial activity was established.
- Jayashree,Thejaswini,Nayak, Yogendra,Kumar, D. Vijay
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experimental part
p. 1055 - 1066
(2012/03/26)
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- Bioconversion of aromatic compounds by Escherichia coli that expresses cytochrome P450 CYP153A13a gene isolated from an alkane-assimilating marine bacterium Alcanivorax borkumensis
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The cytochrome P450 CYP153 family has been isolated from alkane-assimilating bacteria. CYP153 has been shown to mediate terminal hydroxylations of linear alkanes or alkyl aromatics. We here performed the biotransformation of various aromatic compounds by Escherichia coli cells that expressed the CYP153A13a (P450balk) gene, which was isolated from an alkane-degading marine bacterium Alcanivorax borkumensis. Aromatic compounds including a short alkyl moiety or methyl ether moiety, and phenolic compounds were converted to their respective hydroxylated products, whose structures were determined by HRMS and NMR analyses. The present study revealed that the catalytic function of CYP153A13a is multifunctional, i.e., it can hydroxylate not only the terminal of short alkyl groups that attached to aromatic rings but also the p-position of phenolic compounds substituted with a halogen or the acetyl group. CYP153A13a was also shown to demethylate methylether-including aromatic compounds.
- Otomatsu, Toshihiko,Bai, Liming,Fujita, Naoya,Shindo, Kazutoshi,Shimizu, Keiko,Misawa, Norihiko
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experimental part
p. 234 - 240
(2011/01/03)
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- Conformational analysis and interpretation of ν(OH) bands in the IR spectra of 1′-hydroxyethyl derivatives of 1,4-benzo- and 5,8-dihydroxy-1,4-naphthoquinones: A DFT study
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Detailed conformational analysis of the molecule of 1′-hydroxyethyl- 1,4-benzoquinone (3) by the B3LYP/cc-pVTZ method revealed predominance of rotamers with the free 1′-OH group in the gas phase. B3LYP/cc-pVTZ calculations with inclusion of solvent (cyclohexane) effect in the framework of the polarizable continuum model predict an increase in the percentage of such rotamers compared to the corresponding gas-phase values. The results obtained are in qualitative agreement with the experimentally observed pattern of ν(OH) bands in the IR spectrum of compound 3 in cyclohexane (hexane) solution. Conformational analysis, in cluding tautomerism and rotamerism, of 2-ethyl-1′,5,8-trihydroxy-1,4-naphthoquinone (2) was performed by the B3LYP method with the 6-31G(d), 6-311G(d), 6-311G(d,p), and cc-pVDZ basis sets. The most abundant tautomeric form of compound 2 is form A in which the substituent bearing 1 '-OH group is in the quinonoid nucleus. In the gas phase, the percentage of all rotamers in form A is about 86% (among them, the proportion of rotamers with the free 1'-OH group is more than 60%). The main reason for splitting of the v(OH) bands in the IR spectra of compounds 2 and 3 in solutions in nonpolar solvents is the equilibrium between rotamers with a relatively weak intramolecular hydrogen bond between the 1′-OH group and the carbonyl group and those having no this bond.
- Glazunov,Berdyshev,Pokhilo,Anufriev
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experimental part
p. 663 - 674
(2010/08/08)
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- DNA-binding study of nickel(II) and zinc(II) complexes with two novel chromenone-based Schiff-base ligands
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Two new chromenone-based Schiff-base ligands, 3-{[(1,5-dihydro-3-methyl-5- thioxo-4H-1,2,4-triazol-4-yl)imino]methyl}-6-hydroxy-4H-1-benzopyran-4-one (L1) and 2,2′-bis[(6-hydroxy-4-oxo-4H-1-benzopyran-3-yl) methylene]carbonothioic dihydrazide (L2), and their NiII and ZnII complexes were prepared. All the complexes were characterized by elemental analysis, IR data, and molar conductivity. The binding of these four complexes to calf-thymus DNA was carefully investigated by UV/VIS spectroscopy, fluorescence spectroscopy, viscosity measurements, and CD spectra. The experimental results indicate that the four complexes bind to calf-thymus DNA in an intercalative mode, with the intrinsic binding constants (K) of 3.94·104 ([NiL1]), 5.15·10 3 ([ZnL1]), 4.12·104 ([NiL 2]), and 3.75·104 m-1 ([ZnL 2]). These data show that the complexes of L2 can interact more strongly with DNA than complexes of L1, and the NiII complexes have a higher binding constant than ZnII complexes.
- Qin, Dong-Dong,Yang, Zheng-Yin,Li, Tian-Rong,Qi, Gao-Fei
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experimental part
p. 525 - 535
(2009/09/05)
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- Synthesis, characterization, cytotoxic activity and DNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazone
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A new ligand L, 6-hydroxy chromone-3-carbaldehyde thiosemicarbazone, and its Ni(II) complex have been synthesized and characterized. The crystal structure of Ni(II) complex was determined by single crystal X-ray diffraction. Ni(II) complex and ligand L were subjected to biological tests in vitro using THP-1, Raji and Hela cancer cell lines. Compared with the ligand, Ni(II) complex showed significant cytotoxic activity against these three cancer cell lines. The interactions of Ni(II) complex and ligand L with calf thymus DNA were then investigated by spectrometric titration, ethidium bromide displacement experiments and viscosity measurements methods. The experimental results indicated that Ni(II) complex bound to DNA by intercalative mode via the ligand L. The intrinsic binding constants of Ni(II) complex and ligand L with DNA were (1.10 ± 0.65) × 106 M-1 and (1.48 ± 0.57) × 105 M-1, respectively.
- Wang, Bao-dui,Yang, Zheng-Yin,Lü, Ming-hua,Hai, Jun,Wang, Qin,Chen, Zhong-Ning
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scheme or table
p. 4069 - 4075
(2010/03/04)
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- Studies on quinones. Part 42: Synthesis of furylquinone and hydroquinones with antiproliferative activity against human tumor cell lines
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The preparation of furyl-1,4-quinone and hydroquinones by reaction of 2-furaldehyde N,N-dimethylhydrazone with benzo- and naphthoquinones is reported. Access to furylnaphthoquinones from unactivated quinones requires acid-induced conditions, however oxidative coupling reactions of activated quinones proceed under neutral conditions. The in vitro cytotoxic activity of the prepared compounds against a panel of three human cancer cell lines has been studied. Most of the furyl-1,4-quinones exhibited good antiproliferative activity (GI50 = 6.5-33.5 μm) against the MCF-7, NCI-H460, and SF-268 (CNS cancer) cell lines chosen for testing.
- Benites, Julio,Valderrama, Jaime A.,Rivera, Felipe,Rojo, Leonel,Campos, Nair,Pedro, Madalena,Jose Nascimento, Maria Saeo
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p. 862 - 868
(2008/09/17)
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- Regioselective ortho-acylation of phenol and naphthol derivatives catalyzed by FeCl3 under microwave conditions
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Phenol and naphthol derivatives were subjected to regioselective solvent-free ortho-acylation with organic acids in the presence of FeCl 3 under microwave irradiation. The reactions were complete in a short time, and the products were obtained in high yields.
- Naeimi,Moradi
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body text
p. 1757 - 1759
(2009/09/29)
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- Spinazarin and ethylspinazarin, pigments of the sea urchin Scaphechinus mirabilis
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2,3,5,8-Tetrahydroxy-1,4-naphthoquinone (spinazarin) and 6-ethyl-2,3,5,8-tetrahydroxy-1,4-naphthoquinone (ethylspinazarin) were first isolated from the sea urchin Scaphechinus mirabilis. The structures of spinazarins were established based on analysis of spectroscopic data. A preparative synthetic route to ethylspinazarin was proposed.
- Yakubovskaya,Pokhilo,Mishchenko,Anufriev
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p. 819 - 822
(2008/04/05)
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- Demethylation of aryl methyl ethers using pyridinium p-toluenesulfonate under microwave irradiation
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Aryl methyl ethers are deprotected in high yields using pyridinium p-toluenesulfonate under microwave irradiation and solvent-free conditions.
- Lamba, Mandeep S.,Makrandi, Jagdish K.
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p. 585 - 586
(2008/09/17)
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- Microwave assisted direct ortho-acylation of phenol and naphthol derivatives by BF3·(C2H5)2O
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The solventless acylation of phenol and naphthol derivatives with various organic acids and BF3·(C2H5) 2O, under microwave conditions, was studied. High yields of the o-acylated products were achieved in a very short time.
- Naeimi, Hossein,Moradi, Leila
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p. 284 - 287
(2008/02/04)
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- Selectivity adjustment in the cleavage of allyl phenyl and methyl phenyl ethers with boron trifluoride-methyl sulfide complex
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Cleavage of model allyl phenyl and methyl phenyl ethers with boron trifluoride-methyl sulfide complex is described. The demonstrated strong dependence of the reaction rate on the substitution pattern of the phenyl ring and the reaction conditions make it potentially possible to selectively cleave a single methoxy (or allyloxy) group in poly methoxy (or allyloxy) compounds. Georg Thieme Verlag Stuttgart.
- Konieczny, Marek T.,Maciejewski, Grzegorz,Konieczny, Wojciech
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p. 1575 - 1577
(2007/10/03)
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- QSAR studies of paeonol analogues for inhibition of platelet aggregation
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Various paeonol analogues were synthesized and tested in vitro as inhibitors of platelet aggregation. Structural properties (or descriptors) of paeonol analogues were calculated and the structure-activity relationships were determined. Several multiple linear and nonlinear regression models and back-propagation neural network model were tested and the latter using relative positive charge, hydration energy, and hydrophilic factor as inputs gave the best data fitting with R2 = 0.89 and qpre2=0.66. The correlation coefficient between antiplatelet inhibition activity with an interaction energy between the paeonol compounds with COX-1 enzyme is only 0.39.
- Doble, Mukesh,Karthikeyan,Padmaswar,Akamanchi
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p. 5996 - 6001
(2007/10/03)
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- Photohydrodimerization of 6-methoxyflavone to 6,6″-dimethoxy-2, 2″-biflavanones
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6-Methoxyflavone (7) easily afforded two hydrodimers of rac-6,6″-dimethoxy-2,2″-biflavanone (8a) and meso-6,6″- dimethoxy-2,2″-biflavanone (8b) and one reductive product of 6-methoxyflavanone (9) by using photolysis with the electron-donating amines including triethylamine, 2-(N,N-dimethylamino)ethanol or N,N-dimethylaniline in solvents of acetonitrile, benzene or methylene dichloride. They were found to give higher yields of rac-6,6″-dimethoxy-2,2″-biflavanone (8a) and meso-6,6″-dimethoxy-2,2″-biflavanone (8b) (38.7% and 4.5%, 35.3% and 6.2%, respectively) in the reaction conditions of 1/10 molar ratio of 6-methoxyflavone (7) to triethylamine in a solvent of acetonitrile with irradiation of twenty-four hours by using 306 nm and 352 nm lamps.
- Chen, Arh-Hwang,Kuo, Wei-Bao,Chen, Chia-Wen
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p. 1389 - 1394
(2007/10/03)
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- Zinc Mediated Friedel-Crafts Acylation in Solvent-Free Conditions under Microwave Irradiation
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Zn powder is found to catalyze the Friedel-Crafts acylation of aromatic compounds with acyl halides efficiently under microwave irradiation in solvent-free conditions. Activated substrates undergo acylation predominantly at the para-position. The Zn powder can be re-used up to six times after simple washing with diethyl ether and dilute HCl.
- Paul, Satya,Nanda, Puja,Gupta, Rajive,Loupy, Andre
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p. 2877 - 2881
(2007/10/03)
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- Studies on quinones. Part 35: Access to antiprotozoal active euryfurylquinones and hydroquinones
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(+)-Euryfuran adds regiospecifically to activated monosubstituted 1,4-benzoquinones under mild conditions to give the corresponding Michael adducts which, depending on the quinone substituent, undergo in situ redox reactions to the respective euryfurylbenzoquinones. One of these Michael adducts undergoes a facile stereoselective cyclisation under oxidant conditions to afford a naphthofuro[4,3-c]benzopyran derivative. The in vitro activities of the obtained euryfurylquinones and hydroquinones against Leishmania amazonensis are described.
- Valderrama, Jaime A.,Benites, Julio,Cortés, Manuel,Pessoa-Mahana, David,Prina, Eric,Fournet, Alain
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p. 881 - 886
(2007/10/03)
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- Thermal cross fries acyl and benzoyl migrations from aromatic diesters to phenols
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A study of boron trifluoride etherate catalyzed thermal cross Fries reaction is reported in this paper. Acyl and benzoyl migrations from various aromatic diesters to phenols in dry benzene as solvent takes place selectively and in this, way offers an alternative route to the preparation of different hydroxy acetophenones and benzophenones.
- Thapliyal,Aggarwal
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p. 706 - 708
(2007/10/03)
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- Synthetic Utility and Mechanistic Implications of the Fries Rearrangement of Hydroquinone Diesters in Boron Trifluoride Complexes
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Reactions of boron trifluoride methyl and ethyl etherate complexes with hydroquinone diesters yield monomethyl and monoethyl derivatives of acetylhydroquinones. The use of sterically hindered boron trifluoride etherate complexes results in acetylhydroquinone derivatives. This procedure represents a one-step synthesis of acetylhydroquinone derivatives, important building blocks for a variety of synthetic applications.
- Boyer, Jessica L.,Krum, Jodie E.,Myers, Michael C.,Fazal, Aleem N.,Wigal, Carl T.
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p. 4712 - 4714
(2007/10/03)
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- Regiospecific Michael reaction of (+)-euryfuran with activated 1,4- benzoquinones
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(+)-Euryfuran cycloadds regiospecifically to activated monosubstituted 1,4-benzoquinones under mild conditions to give the corresponding Michael adducts which, depending on the quinone substituent, undergo in situ redox reactions to the respective euryfurylbenzoquinones. One of the reported Michael adducts undergoes a facile stereoselective cyclisation under oxidant conditions to afford a naphthofuro[4,3-c]benzopyran derivative. The regiospecificity of the Michael and cyclisation reactions are discussed. (C) 2000 Elsevier Science Ltd.
- Valderrama, Jaime A.,Cortés, Manuel,Pessoa-Mahana, David,Preite, Marcelo,Benites, Julio
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p. 3563 - 3566
(2007/10/03)
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- Tandem Fries Reaction-Conjugate Addition under Microwave Irradiation in Dry Media; One-pot Synthesis of Flavanones
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An AlCl3-ZnCl2 mixture supported on silica gel is found to be an efficient medium for the Fries rearrangement of acyloxybenzene or naphthalene derivatives in solvent-free conditions under microwave irradiation.
- Moghaddam, Firouz Matloubi,Ghaffarzadeh, Mohammad,Abdi-Oskoui, Seyed Hossein
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p. 574 - 575
(2007/10/03)
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- Synthesis and in-vitro evaluation of platelet aggregation inhibitory activity of paeonol and its analogues
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Paeonol (1-(2-hydroxy-4-methoxyphenyl)ethanone) and a series of substituted 1-(2-hydroxyphenyl)ethanone derivatives were synthesized and screened as inhibitors of platelet aggregation. The compounds with the greatest anti-platelet potential among the series tested were 1-(2,5-dihydroxyphenyl)ethanone (65.36% inhibition at 300 μM against 5 μM ADP), paeonol(36.31%), 1-(2-hydroxy-5-methoxyphenyl)ethanone (24.47%), 1-(2-hydroxy-5-nitrophenyl) ethanone (30.40%) and 1-(5-chloro-2-hydroxy-4-methylphenyl)ethanone (24.43%).
- Akamanchi,Padmawar,Thatte,Rege,Dahanukar
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p. 323 - 329
(2007/10/03)
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- A direct route to acylhydroquinones from α-keto acids and α- carboxamido acids
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The reaction of quinones with in situ generated acyl- or carboxamido radicals provides a direct rome to the synthesis of acylhydroquinones not accessible by the photochemical reaction of quinones with aldehydes.
- Kraus, George A.,Melekhov, Alex
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p. 3957 - 3960
(2007/10/03)
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- Alumina in Methanesulfonic Acid (AMA) as a New Efficient Reagent for Direct Acylation of Phenol Derivatives and Fries Rearrangement. A Convenient Synthesis of o-Hydroxyarylketones
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Alumina in methanesulfonic acid (AMA) is used to prepare o-hydroxyaryl ketones by acylation of phenol and naphthol derivatives with carboxylic acids and the Fries rearrangement of phenolic esters. Mechanistic studies show that the acylation reaction in AMA occurred through an esterification followed by a Fries rearrangement of the phenolic ester by an intermolecular mechanism.
- Sharghi, Hashem,Kaboudin, Babak
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p. 2678 - 2695
(2007/10/03)
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- Method for dyeing keratinous fibres using a monohydroxyindole or dihydroxyindole and a non-oxidizing aromatic carbonyl derivative and dyeing agent
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The present invention relates to a method for dyeing keratinous fibers, characterized in that the following are applied to the fibers: a) a composition (A) containing, in a medium appropriate for dyeing, at least one monohydroxyindole or dihydroxyindole, this application being preceded or followed by the application of b) a composition (B) containing, in a medium appropriate for dyeing, at least one aromatic carbonyl derivative chosen from hydroxyacetophenones, hydroxybenzophenones, 2-hydroxy-1,4-benzoquinones, hydroxy-1,4-naphthoquinones,amino-1,4-naphthoquinones,hydroxy-9,10-anthraquinones and amino-9,10-anthraquinones. It also relates to the dyeing agents for carrying it out.
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- Reaction of Acetic Anhydride/Zinc Chloride Reagent with Phenols: Improved Yields of Hydroxyacetophenones
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Acetic anhydride/zinc chloride has been found to be a better acylating system for phenol and polyphenols resulting in improved yields of the respective hydroxyacetophenones.The phenols used are phenol, resorcinol, hydroquinonone, catechol, phloroglucinol and pyrogallol.With resorcinol the isomeric diacetyl derivatives are formed in excellent yields in a single step, while catechol and hydroquinone give only monoacetyl derivatives like simple phenol.Pyrogallol gives a monoacetyl derivative while phloroglucinol gives both mono and diacetyl derivatives but not triacetyl derivatives.
- Anjaneyulu, A. S. R.,Mallavadhani, U. V.,Venkateswarlu, Y.,Prasad, A. V. Rama
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p. 823 - 826
(2007/10/02)
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