- A metal-free heterogeneous photocatalyst for the selective oxidative cleavage of CC bonds in aryl olefins: via harvesting direct solar energy
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Selective cleavage of CC bonds is highly important for the synthesis of carbonyl containing fine chemicals and pharmaceuticals. Novel methodologies such as ozonolysis reactions, Lemieux-Johnson oxidation reaction etc. already exist. Parallel to these, catalytic methods using homogeneous catalysts also have been discovered. Considering the various advantages of heterogeneous catalysts such as recyclability and stability, couple of transition metal-based heterogeneous catalysts have been applied for this reaction. However, the pharmaceutical industries prefer to use metal-free catalysts (especially transition metal-free) to avoid further leaching in the final products. This is for sure a big challenge to an organic chemist and to the pharmaceutical industries. To make this feasible, a mild and efficient protocol has been developed using polymeric carbon nitrides (PCN) as metal-free heterogeneous photocatalysts to convert various olefins into the corresponding carbonyls. Later, this catalyst has been applied in the gram scale synthesis of pharmaceutical drugs using direct solar energy. Detailed mechanistic studies revealed the actual role of oxygen, the catalyst, and the light source.
- Das, Shoubhik,Hatami, Nareh,Jooss, Christian,Lange, Niklas Simon,Ronge, Emanuel,Schilling, Waldemar,Zhang, Yu
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supporting information
p. 4516 - 4522
(2020/08/10)
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- Reinvestigation of acetylation of 3,4-dihydroxybenzaldehyde and reconciliation of previously reported analytical data
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Acetylation of 3,4-dihydroxybenzaldehyde was reinvestigated. The results in the regiochemical outcome were analyzed in detail by NMR methods and compared with previously published data.
- Albi?ana, Carlos Berenguer,Hayward, John J.,Hudlicky, Tomas,Machara, Ales
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supporting information
p. 1019 - 1021
(2016/02/18)
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- Preliminary antiproliferative evaluation of natural, synthetic benzaldehydes and benzyl alcohols
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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
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p. 1814 - 1816
(2014/03/21)
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- Synthesis of catechols from phenols via Pd-catalyzed silanol-directed C-H oxygenation
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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
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p. 17630 - 17633
(2011/12/16)
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- First synthesis, characterization, and evidence for the presence of hydroxycinnamic acid sulfate and glucuronide conjugates in human biological fluids as a result of coffee consumption
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A systematic investigation of the human metabolism of hydroxycinnamic acid conjugates was carried out. A set of 24 potential human metabolites of coffee polyphenols has been chemically prepared, and used as analytical standards for unequivocal identifications. These included glucuronide conjugates and sulfate esters of caffeic, ferulic, isoferulic, m-coumaric and p-coumaric acids as well as their dihydro derivatives. A particular focus has been made on caffeic and 3,4-dihydroxyphenylpropionic acid derivatives, especially the sulfate conjugates, for which regioselective preparation was particularly challenging, and have so far never been identified as human metabolites. Ten out of the 24 synthesized conjugates have been identified in human plasma and/or urine after coffee consumption. A number of these conjugates were synthesized, characterized and detected as hydroxycinnamic acid metabolites for the first time. This was the case of dihydroisoferulic acid 3′-O-glucuronide, caffeic acid 3′-sulfate, as well as the sulfate and glucuronide derivatives of 3,4-dihydroxyphenylpropionic acid.
- Fumeaux, Rene,Menozzi-Smarrito, Candice,Stalmach, Angelique,Munari, Caroline,Kraehenbuehl, Karin,Steiling, Heike,Crozier, Alan,Williamson, Gary,Barron, Denis
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experimental part
p. 5199 - 5211
(2010/12/25)
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- New insight into the oxidative chemistry of noradrenaline: Competitive o-quinone cyclisation and chain fission routes leading to an unusual 4-[bis-(1H-5,6-dihydroxyindol-2-yl)methyl]-1,2-dihydroxybenzene derivative
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Oxidation of 5×10-3 M noradrenaline in aqueous phosphate buffer, pH 7.4, with K3Fe(CN)6, NaIO4 or Fe2+/EDTA/H2O2 followed by extraction with ethyl acetate and acetylation with Ac2O/Pyr led to a main reaction product which was isolated and identified as 4-[bis-(1H-5,6-diacetoxyindol-2-yl) methyl]-1,2-diacetoxybenzene, an unprecedented [bis-(indol-2-yl)methyl]-benzene derivative unsubstituted on the 3-position of the indole rings. This product was also obtained in 40% yield by reaction of 5,6-dihydroxyindole with 3,4-dihydroxybenzaldehyde. Other components of the oxidation mixture were 1-acetyl-3,5,6-triacetoxyindole, derived from noradrenolutin, and 5,6-diacetoxyindole, originating from cyclisation/dehydration of the o-quinone of noradrenaline, along with some 3,4-diacetoxybenzaldehyde. Inspection of the aqueous phase revealed the presence of 3,4-dihydroxymandelic acid and 3,4-dihydroxybenzaldehyde, derived from oxidative breakdown of the 2-amino-1-hydroxyethyl chain via a p-quinomethane intermediate. These results disclose new aspects of the oxidative chemistry of noradrenaline beyond the aminochrome stage and provide a route to novel [bis-(indol-2-yl)methyl]-benzene derivatives of potential pharmacological interest.
- Manini, Paola,Pezzella, Alessandro,Panzella, Lucia,Napolitano, Alessandra,D'Ischia, Marco
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p. 4075 - 4080
(2007/10/03)
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- Total synthesis of ustiloxin D and considerations on the origin of selectivity of the asymmetric allylic alkylation
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As part of investigations into cell cycle checkpoint inhibitors, an asymmetric synthesis of the antimitotic natural product, ustiloxin D, has been completed. A salen-Al-catalyzed aldol reaction was employed to construct a chiral oxazoline 9 (99% yield, 98
- Sawayama, Andrew M.,Tanaka, Hiroko,Wandless, Thomas J.
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p. 8810 - 8820
(2007/10/03)
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- Lipase catalysed regioselective esterification of protocatechuic aldehyde
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Protocatechuic aldehyde (3,4-dihydroxybenzaldehyde-PA) is acetylated using acetic anhydride in presence of porcine pancreas lipase and two preparations of Rhizomucor miehei to give a mixture of 3-acetoxy and 3,4-diacetoxy derivatives in good yields. All the three lipases show better selectivity towards formation of 3-acetoxy-4-hydroxybenzaldehyde than the diacetoxy and 4-acetoxy derivatives.
- Divakar, Soundar
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p. 1119 - 1122
(2007/10/03)
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- Treating agent for osteroarthritis
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The present invention discloses a method for treating a patient suffering from osteoarthritis comprising administering a physiologically effective amount of pharmaceutical composition containing at least one compound, as an active ingredient, represented by the formula (I): STR1 wherein R represents a hydrogen atom or an acyl group; X represents a CHO group, a COOH group, a physiologically acceptable salt thereof or a CH(OR')2 group wherein R' represents an acyl group.
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- Studies on the Synthesis of Heterocyclic Compounds. XVI. Cleavage of 1,3-Benzodioxoles and -Benzoxathioles by Sodium Iodide-Acyl Chloride
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The cleavage reaction of ethereal and thioethereal bonds with sodium iodide and acyl chloride has been studied.In all the 1,3-benzodioxoles and -benzoxathioles studied, the opening of the heterocyclic ring with formation of 1,2-diacetoxybenzene or 2-hydroxythiophenol diacetic acid ester and gem-diiodoalkanes and iodoalkenes has been observed.The structure of newly prepared compounds has been determined by analytical and spectroscopic data or comparison with authentic samples.
- Corda, Luciana,Fadda, Anna Maria,Maccioni, Antonio,Maccioni, Anna Maria,Podda, Gianni
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p. 311 - 314
(2007/10/02)
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