- Synthesis of 1-(Indol-2-yl)-phenoxazine hybrids from quinacetophenone precursors and their biological evaluation as DNA intercalating agents
-
An operationally simple reaction between quinacetophenone and aniline derivatives in the presence of triethylamine at room temperature afforded 1-(indol-2-yl)-phenoxazine hybrids in good yields. This unique transformation proceeds via sequential aza-Micha
- Dixit, Apoorva,Godugu, Chandraiah,Kotla, Naveen,Lakshmi Uppu, Jaya,Nunewar, Saiprasad N.,Pooladanda, Venkatesh,Tangellamudi, Neelima D.
-
-
Read Online
- Quinacetophenone: A simple precursor for synthesis of phenoxazines
-
Quinacetophenone is a versatile and easy accessible building block for synthesis of various biologically active heterocyclic compounds. The inherent chemical reactivity of quinacetophenone has been hitherto utilized to construct various privileged organic molecules such as chalcones, chromones, flavonoids, coumarins and azoles etc. Herein we present an operationally simple method of synthesis of phenoxazines from quinacetophenone and anilines that exploits the inherent chemical reactivity of quinacetophenone. ESI-MS was used as a tool to establish the most plausible reaction mechanism.
- Nunewar, Saiprasad N.,Muthyala, Bhavana B.,Dastari, Sowmya,Tangellamudi, Neelima D.
-
-
Read Online
- Synthesis of antiplatelet ortho-carbonyl hydroquinones with differential action on platelet aggregation stimulated by collagen or TRAP-6
-
Cardiovascular diseases are the leading cause of death in the world. Platelets have a major role in cardiovascular events as they bind to the damaged endothelium activating and forming thrombi. Although some hydroquinone scaffold-containing compounds have known antiplatelet activities, currently there is a lack of evidence on the antiplatelet activity of hydroquinones carrying electron attractor groups. In this work, we evaluate the antiplatelet effect of a series of ortho-carbonyl hydroquinone derivatives on cytotoxicity and function of human platelets, using collagen and thrombin receptor activator peptide 6 (TRAP-6) as agonists. Our structure-activity relationship study shows that gem-diethyl/methyl substitutions and the addition/modifications of the third ring of ortho-carbonyl hydroquinone scaffold influence on the selective index (IC50 TRAP-6/IC50 Collagen) and the inhibitory capacity of platelet aggregation. Compounds 3 and 8 inhibit agonist-induced platelet aggregation in a non-competitive manner with IC50 values of 1.77 ± 2.09 μM (collagen) and 11.88 ± 4.59 μM (TRAP-6), respectively and show no cytotoxicity. Both compounds do not affect intracellular calcium levels and mitochondrial bioenergetics. Consistently, they reduce the expression of P-selectin, activation of glycoprotein IIb/IIIa, and release of adenosine triphosphate and CD63 from platelet. Our findings may be used for further development of new drugs in platelet-related thrombosis diseases.
- Araya-Maturana, Ramiro,Fuentes, Eduardo,Millas-Vargas, Juan Pablo,Alarcón, Marcelo,Méndez, Diego,Palomo, Iván,Rodríguez-Lavado, Julio,Trostchansky, Andrés,Urra, Félix A.
-
-
Read Online
- Silica-gel-supported ceric ammonium nitrate (CAN): A simple and efficient solid-supported reagent for oxidation of oxygenated aromatic compounds to quinones
-
A silica-gel-supported heterogeneous ceric ammonium nitrate (CAN) reagent has been developed for oxidizing oxygenated aromatics to quinones in nonaqueous media. The advantages of this procedure include excellent yields, mild reaction conditions, nonaqueous media, short reaction times, and easy product isolation. Copyright Taylor & Francis Group, LLC.
- Ali, Mohammed Hashmat,Niedbalski, Melinda,Bohnert, Gary,Bryant, Daniel
-
-
Read Online
- Synthesis of pyrrolo[3,2-b]benzofurans and pyrrolo[3,2-b]naphthofurans via addition of a silyloxypyrrole to activated quinones
-
The uncatalyzed reaction of N-(tert-butoxycarbonyl)-2-tert- butyldimethylsilyloxypyrrole 3 with 1,4-quinones bearing an electron withdrawing group at C-2 has been studied. Use of 1,4-quinones 4, 5 bearing an ester group at C-2 provided an efficient synthe
- Brimble, Margaret A.,Burgess, Caryn,Halim, Rosliana,Petersson, Maria,Ray, Jayanta
-
-
Read Online
- The synthesis of some fused pyrazolo-1,4-naphthoquinones
-
New fused pyrazolo-1,4-naphthoquinones were prepared from the reaction of hydrazines with 6-(4-methyl-3-pentenyl)-1,4-naphthoquinone. The reaction was extended to hydroxylamine to afford the corresponding isoxazolo-1,4-napthoquinone compound.
- Molinari, Aurora,Oliva, Alfonso,Arismendi, Marlene,Imbarack, Elizabeth,Gálvez, Cristian,Maldonado, Javier,Feliciano, Arturo San
-
-
Read Online
- Experimental and Theoretical Justification for the Regiospecific Cycloaddition of Levopimaric Acid to 2-Acetyl- or 2-(Methoxycarbonyl)-1,4-Benzoquinone
-
New 4a-quinopimaric acid derivatives were synthesized via a Diels-Alder reaction of levopimaric acid with 2-acetyl- or 2-(methoxycarbonyl)-1,4-benzoquinone and were characterized using elemental analysis and NMR spectroscopy. Thermodynamic and activation
- Vafina,Borisevich,Uzbekov,Poptsov,Spirikhin,Khursan
-
-
Read Online
- Cytotoxic-antineoplastic activity of acetyl derivatives of prenylnaphthohydroquinone
-
Several acetyl derivatives of prenylnaphthohydroquinone have been synthetised and evaluated for their cytotoxicity against A-549 human lung carcinoma and H-116 human colon carcinoma neoplastic cells. The IC50 values against A-549 are compared w
- Molinari, Aurora,Oliva, Alfonso,Del Corral, Jose Ma. Miguel,Castro, Ma. Angeles,Araya, Claudia,Garcia-Gravalos, Ma. Dolores,San Feliciano, Arturo
-
-
Read Online
- Assessing parameter suitability for the strength evaluation of intramolecular resonance assisted hydrogen bonding in O-carbonyl hydroquinones
-
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
-
-
- Half-wave potentials and in vitro cytotoxic evaluation of 3-acylated 2,5-bis(phenylamino)-1,4-benzoquinones on cancer cells
-
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
-
-
- Studies on quinones. Part 47. Synthesis of novel phenylaminophenanthridinequinones as potential antitumor agents
-
In our search for potential anticancer agents, a series of 8- and 9-phenylamino-3,4-tetrahydro-phenanthridine-1,7,10(2H)-triones with substituent variations at 6-, 8- and 9-positions were prepared using a highly efficient sequence involving: a) solar photoacylation reactions of benzoquinone with arylaldehydes, b) one-pot procedure for the synthesis of 3,4- dihydrophenanthridine-1,7,10(2H)-trione intermediates from acylhydroquinones and c) highly regiocontrolled acid-induced amination reaction of phenanthridinequinones with phenylamines. The members of this series were in vitro evaluated using the MTT colorimetric method against one normal cell line and three human cancer cell lines. The SAR analysis indicates that the location of nitrogen substituents on the quinone nucleus, the presence of methyl, phenyl, furyl and thienyl groups at the 6-position and the aromatization of the angular cycloaliphatic ring of the phenylamino-3,4-tetrahydrophenanthridine-1,7,10(2H)- trione pharmacophore play key roles in the antitumor activity.
- Valderrama, Jaime A.,Ibacache, Andrea,Rodriguez, Jaime A.,Theoduloz, Cristina,Benites, Julio
-
scheme or table
p. 3398 - 3409
(2011/08/03)
-
- Aerobic oxidation of hydroquinone derivatives catalyzed by polymer-incarcerated platinum catalyst
-
(Chemical Equation Presented) It's a lock-in! A remarkably wide substrate scope of hydroquinones are oxidized to quinones in high yields in a platinum-catalyzed process with as low as 0.05 mol% catalyst. The aerobic oxidation is catalyzed by platinum nanoclusters trapped in a styrene-based polymer network (see scheme, PI Pt=polymer-incarcerated nanoclusters). The catalyst could be reused at least 13 times without any loss of catalytic activity.
- Miyamura, Hiroyuki,Shiramizu, Mika,Matsubara, Ryosuke,Kobayashi, Shu
-
supporting information; experimental part
p. 8093 - 8095
(2009/04/13)
-
- Design and synthesis of angucyclinone 5-aza analogues
-
A highly efficient one-pot procedure for the synthesis of phenanthridine-1,7,10-triones from acylbenzoquinones and cyclic enaminones is reported. The cycloaddition reactions of these quinones with 1-trimethylsilyloxybutadiene followed by hydrolysis and oxidative processes provide entry to a variety of angucyclinone 5-aza analogues. Georg Thieme Verlag Stuttgart.
- Valderrama, Jaime A.,González, M. Florencia,Colonelli, Pamela,Vásquez, David
-
p. 2777 - 2780
(2008/02/11)
-
- Nuclear amination catalyzed by fungal laccases: Reaction products of p-hydroquinones and primary aromatic amines
-
(Chemical Equation Presented) Nuclear amination of p-hydroquinones with primary aromatic amines was catalyzed by fungal laccases (EC 1.10.3.2) from Trametes spec. and Myceliophthora thermophila. This is the first report of laccase-catalyzed synthesis of aminoquinones. Incubation of two compounds with laccase in the presence of oxygen resulted in the formation of the corresponding monoaminated or diaminated quinones. No hydroquinonoids were formed. Observed differences in the reaction courses for different p-hydroquinones and aromatic amines with different laccases are discussed.
- Niedermeyer, Timo H. J.,Mikolasch, Annett,Lalk, Michael
-
p. 2002 - 2008
(2007/10/03)
-
- Studies on quinones. Part 39: Synthesis and leishmanicidal activity of acylchloroquinones and hydroquinones
-
Acylhydroquinone-based compounds are attractive targets for the design of new leishmanicidal drugs. We have previously described sesquiterpene quinones and hydroquinones series, which exhibit different degree of potency against Leishmania amazonensis. The present study details the preparation of acylchloroquinones and hydroquinones possessing lipophilic substituents and examines their in vitro activity against intracellular L. amazonensis amastigotes. The quinone or hydroquinone nucleus is essential for the activity of the members of the series. The lipophilicity of the cycloaliphatic systems in these members seems to attenuate the cytotoxical effect and increases the selectivity of those compounds containing the norbornene system.
- Valderrama, Jaime A.,Zamorano, Carlos,Gonzalez, M. Florencia,Prina, Eric,Fournet, Alain
-
p. 4153 - 4159
(2007/10/03)
-
- 1,4-ADDITION OF 2-TRIMETHYLSILYLOXYFURAN TO QUINONES: A FACILE ROUTE TO THE FUROBENZOFURAN NUCLEUS
-
The uncatalysed addition of 2-trimethylsilyloxyfuran (3) to a range of activated quinones (4) and (6) yields the crystalline adducts (5) and (7) in 51-91percent yield.This novel furofuran-annulation to a quinone system provides a facile entry to the furobenzofuran ring system.
- Brimble, Margaret A.,Gibson, Jennifer J.,Baker, Raymond,Brimble, Mark T.,Kee, Alex A.,O'Mahony, Mary J.
-
p. 4891 - 4892
(2007/10/02)
-
- STUDIES ON QUINONES. XI. SYNTHESIS OF QUINONES FROM HYDROQUINONES BY USING MANGANESE DIOXIDE AND ACID-IMPREGNATED MANGANESE DIOXIDE.
-
The preparation of a variety of quinones by oxidation of hydroquinones with manganese dioxide and manganese dioxide impregnated with nitric acid, in methylene chloride solution, is described.
- Cassis, R.,Valderrama, J. A.
-
p. 347 - 356
(2007/10/02)
-
- MODELS FOR THE PHOTOSYNTHETIC WATER OXIDIZING ENZYME. 2. ELECTRONIC, MAGNETIC, AND EPR CHARACTERIZATION OF A BINUCLEAR MANGANESE(II) SEMIQUINONE COMPLEX.
-
The preparation and characterization of a tetranuclear manganese complex, Mn//4(ASQ)//4(CO)//8, and a binuclear complex into which it dissociates in solution, Mn//2(ASQ)//4L//2 (ASQ equals 2-acetyl-1,4-benzosemiquinone), is described. EPR spectroscopy and
- Mathur,Dismukes
-
p. 7093 - 7098
(2007/10/02)
-