- Gold catalysis for selective hydrogenation of aldehydes and valorization of bio-based chemical building blocks
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Gold catalysts are best known for their selectivity in oxidation reactions, however, there is a promising future for gold in selective hydrogenations. Herein, the hydrogenation of several aldehydes and important bio-based chemical building blocks, namely 5-hydroxymethylfurfural (5-HMF), furfural and vanillin, was performed throughout the combination of Au nanoparticles with Lewis bases. The Au-amine ligand (e.g., 2,4,6-trimethylpyridine) catalytic system could reduce the aldehyde carbonyl group selectively, without reducing alkene moieties or opening the furanic ring that occur on most traditional catalysts. Otherwise, the reduction of nitro group is preferential and the catalytic system was used for the synthesis of furfurylamines, important intermediates in the synthesis of different pharmaceuticals (e.g., furosemide), through the selective reductive amination of furfural starting from nitro-compounds. Moreover, a fully heterogeneous gold catalyst embedded in N-doped carbon (Au@N-doped carbon / TiO2) was able to perform these reactions in successive recycles without the addition of ligands, with impact in the development of a continuous flow process for biomass valorization.
- Silva, Rerison J. M.,Fiorio, Jhonatan L.,Vidinha, Pedro,Rossi, Liane M.
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p. 2162 - 2169
(2019/12/30)
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- Asymmetric Retro-Claisen Reaction by Synergistic Chiral Primary Amine/Palladium Catalysis
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We described herein a chiral primary amine/palladium catalyzed asymmetric retro-Claisen reaction of β-diketones with salicylic carbonates. A series of chiral α-alkylated ketones and macrolides were obtained with good yields and excellent enantioselectivities upon a sequence of decarboxylative benzylation, retro-Claisen cleavage, and enamine protonation. This strategy features broad substrate scope, mild conditions, as well as high atom economy with salicylic carbonates as the o-quinone methide precursors.
- Han, Yanfang,Zhang, Long,Luo, Sanzhong
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supporting information
p. 7258 - 7261
(2019/10/02)
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- Photoresponsive azo-combretastatin A-4 analogues
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Colchicine analogues in which an azo group is incorporated into a molecule containing the key pharmacophore of colchicine, have found particular utility as switchable tubulin binding chemotherapeutics. Combretastatin is a related compound containing a stilbene fragment that shows different bioactivity for the cis and trans isomers. We have performed cell assays on 17 new compounds structurally related to a previously reported azo-analogue of combretastatin. One of these compounds showed enhanced potency against HeLa (IC50 = 0.11 μM) and H157 cells (IC50 = 0.20 μM) for cell studies under 400 nm irradiation and the highest photoactivity (IC50 with irradiation/IC50 in dark = 550). We have performed docking and physicochemical studies of this new compound (7). Kinetic studies in water reveal a longer half-life for the cis isomer of 7 which may be one factor responsible for the better IC50 values in cell assays and the improved photoresponsive behavior.
- Rastogi, Shiva K.,Zhao, Zhenze,Barrett, Scott L.,Shelton, Spencer D.,Zafferani, Martina,Anderson, Hailee E.,Blumenthal, Madeleine O.,Jones, Lindsey R.,Wang, Lei,Li, Xiaopeng,Streu, Craig N.,Du, Liqin,Brittain, William J.
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supporting information
p. 1 - 7
(2017/11/24)
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- Pd-catalyzed reduction of aldehydes to alcohols using formic acid as the hydrogen donor
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Facile and selective reduction of aromatic aldehydes as well as aliphatic aldehydes to alcohols was achieved using formic acid as the hydrogen donor in the presence of a catalytic amount of Pd(OAc)2 and Cy3P. It was found that both hydrogen atoms in the formic acid molecule can serve as the hydride source. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.]
- Wang, Anwei,Yang, Zhiyong,Liu, Jidan,Gui, Qingwen,Chen, Xiang,Tan, Ze,Shi, Ji-Cheng
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supporting information
p. 280 - 288
(2013/12/04)
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- Water-promoted ortho-selective monohydroxymethylation of phenols in the NaBO2 system
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Water-promoted ortho-selective monohydroxymethylation of phenols in the NaBO2 system generates salicyl alcohols in 65-97% yields. A remarkable rate-enhancement by water was observed, and NaBO2 appeared to serve the dual role of a suitable base and an efficient chelating reagent. This protocol possesses many advantages such as short reaction times, expanded substrate scope, and high mono- and regio-selectivities. The experimental results were explained by the calculations based on local ionisation energy minima, leading to a possible reaction mechanism.
- Li, Hui-Jing,Wu, Ying-Ying,Wu, Qin-Xi,Wang, Rui,Dai, Chun-Yang,Shen, Zhi-Lun,Xie, Cheng-Long,Wu, Yan-Chao
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p. 3100 - 3107
(2014/05/06)
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- MAO Inhibitory Activity of 2-Arylbenzofurans versus 3-Arylcoumarins: Synthesis, invitro Study, and Docking Calculations
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Monoamine oxidase (MAO) is an important drug target for the treatment of neurological disorders. Several 3-arylcoumarin derivatives were previously described as interesting selective MAO-B inhibitors. Preserving the trans-stilbene structure, a series of 2-arylbenzofuran and corresponding 3-arylcoumarin derivatives were synthesized and evaluated as inhibitors of both MAO isoforms, MAO-A and MAO-B. In general, both types of derivatives were found to be selective MAO-B inhibitors, with IC50 values in the nano- to micromolar range. 5-Nitro-2-(4-methoxyphenyl)benzofuran (8) is the most active compound of the benzofuran series, presenting MAO-B selectivity and reversible inhibition (IC50=140nM). 3-(4′-Methoxyphenyl)-6-nitrocoumarin (15), with the same substitution pattern as that of compound 8, was found to be the most active MAO-B inhibitor of the coumarin series (IC50=3nM). However, 3-phenylcoumarin 14 showed activity in the same range (IC50=6nM), is reversible, and also severalfold more selective than compound 15. Docking experiments for the most active compounds into the MAO-B and MAO-A binding pockets highlighted different interactions between the derivative classes (2-arylbenzofurans and 3-arylcoumarins), and provided new information about the enzyme-inhibitor interaction and the potential therapeutic application of these scaffolds.
- Ferino, Giulio,Cadoni, Enzo,Matos, Maria Joao,Quezada, Elias,Uriarte, Eugenio,Santana, Lourdes,Vilar, Santiago,Tatonetti, Nicholas P.,Yanez, Matilde,Vina, Dolores,Picciau, Carmen,Serra, Silvia,Delogu, Giovanna
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p. 956 - 966
(2013/07/27)
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- One-pot transition-metal-free synthesis of dibenzo[b,f]oxepins from 2-halobenzaldehydes
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A one-pot transition-metal-free, base-mediated synthesis of dibenzo[b,f]oxepins was developed. The reaction of 2-halobenzaldehydes with (2-hydroxyphenyl)acetonitriles proceeds via a sequential aldol condensation and intramolecular ether formation reaction in the presence of Cs2CO 3 and molecular sieves in toluene.
- Choi, Young Lok,Lim, Hye Sun,Lim, Hwan Jung,Heo, Jung-Nyoung
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supporting information
p. 5102 - 5105,4
(2012/12/12)
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- Novel 4-(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolin-2-yl)methylbenzofuran derivatives as selective α2C-adrenergic receptor antagonists
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The synthesis of a series of 4-(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolin-2-yl)methyl-2-arylbenzofuran and 4-(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolin-2-yl)methylbenzofuran-2-carboxamide derivatives as novel α2C-adrenergic receptor antagonists are described. Their affinity at three different human α2-adrenergic receptors is reported, and some of these compounds exhibited high affinity for the α2C-adrenergic receptor with high subtype selectivity. Among them, compound 10e has been found to show the anti-l-dopa-induced dyskinetic activity in marmosets. The structure-activity relationship of these compounds is also discussed.
- Hagihara, Koji,Kashima, Hajime,Iida, Kyoichiro,Enokizono, Junichi,Uchida, Shin-ichi,Nonaka, Hiromi,Kurokawa, Masako,Shimada, Junichi
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p. 1616 - 1621
(2007/10/03)
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- Nucleotide Delivery from cycloSaligenyl-3′-azido-3′-deoxythymidine Monophosphates (cycloSal-AZTMP)
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The application of our cycloSaligenyl- (cycloSal) pronucleotide concept to the approved anti-HIV dideoxynucleoside 3′-azido-3′-deoxythymidine AZT (1) is reported. This pronucleotide concept has been designed to deliver the corresponding 3′-azido-3′-deoxythymidine monophosphate AZTMP (2) by selective chemical hydrolysis from the lipophilic precursors cycloSal-AZTMP 4a-h. All derivatives 4a-h were synthesized using differently substituted salicyl alcohols 7a-h as starting materials. In hydrolysis studies, compounds 4 decomposed selectively releasing AZTMP (2) and the salicyl alcohols 7 following the designed tandem reaction. Furthermore, due to the electronic properties introduced by substituents, the half-lives of the triesters 4 could be ajusted over a wide range. Phosphotriesters 4 exhibited considerable biological activity in HIV-1 and HIV-2 infected wild-type human T-lymphocyte (CEM/O) cells, whereas, contrary to our expectations, nearly all activity was lost in HIV-2 infected thymidine-kinase-deficient CEM cells.
- Meier, Chris,De Clercq, Eric,Balzarini, Jan
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p. 837 - 846
(2007/10/03)
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- As
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The synthesis of cycloSal-AZTMPs 3a-h as new pro-nucleotides of AZTMP 2 is described. Phosphotriesters 3 selectively release AZTMP 2 by a controlled, chemically induced tandem reaction. Cyc/oSal-AZTMPs 3 exhibited high biological activity in HIVl/HIV-2 infected CEM/O cells but lost their activity nearly completely in CEM/TK cells. Copyright
- Meier, Chris,De Clercq, Eric,Balzarini, Jan
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p. 793 - 796
(2007/10/03)
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- New synthesis and antitumor activity of cyclosalderivatives of 5-fluoro-2′-deoxyuridinemonophosphate
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An improved synthesis of 5′-cycloSal-FdUMP 3a-g and 3′,5′-bis-cycloSalFdUMP 9a-g as potential prodrugs of FdU 1 is described. In hydrolysis studies, phosphotriesters 3 released FdUMP 2 selectively by a tandem reaction. The biological activity of cycloSal-phosphotriesters 3 and 9 was evaluated in different cell lines. Copyright
- Lorey, Martina,Meier, Chris,De Clercq, Eric,Balzarini, Jan
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p. 789 - 792
(2007/10/03)
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- Cyclo-saligenyl-2',3'-dideoxy-2',3' didehydroythymidinemonophosphate (cyclosal-d4TMP) - A new pro-nucleotide approach
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The synthesis of cycloSal-d4TMP 3a-g as new pro-nucleotide approach for d4TMP 2 is described. Phosphotriesters 3 release the d4TMP 2 selectively by a controlled, chemically induced tandem reaction. CycloSa1-phosphotriesters 3 exhibited high biological activity against HIV-1/HIV-2 in CEM cells which was completely retained in CEM TK- cells.
- Meier, Chris,Lorey, Martina,De Clercq, Eric,Balzarini, Jan
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p. 1303 - 1306
(2007/10/03)
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- Cyclo-saligenyl-5-fluoro-2′-deoxyuridinemonophosphate (cycloSal-FdUMP), A new prodrug approach for fdump
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The synthesis of cycloSal-FdUMP 3a-d as a new prodrug approach for FdU 1 is described. Phosphotriesters 3 release the FdUMP 2 selectively by a controlled, chemically induced tandem reaction in hydrolysis studies. The biological activity (IC50) of cycloSal-phosphotriesters 3 was evaluated in FM3A/O cells and FM3A/TK- cells. Copyright
- Lorey, Martina,Meier, Chris,De Clercq, Eric,Balzarini, Jan
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p. 1307 - 1310
(2007/10/03)
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- Ortho Lithiation of 2-Hydroxymethyl-1,4,5,6,8-pentamethoxynaphthalene, a Supplement
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The structures of the products in our previous report "One-Pot Hydroxylations of 2-(1-Hydroxyalkyl)naphthalenes and (1-Hydroxyalkyl)benzenes" were reexamined by 13C NMR spectra and part of our previous interpretation will be corrected here.The lithiations of 2-(1-hydroxyalkyl)-1,4,5,6,8-pentamethoxynaphthalenes occurred at the 7-position, and not at the 3-position as were reported.
- Tanoue, Yasuhiro,Terada, Akira
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p. 2295 - 2297
(2007/10/02)
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- One-Pot Ortho Hydroxylation of 2-(1-Hydroxyalkyl)naphthalenes and (1-Hydroxyalkyl)benzenes
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Hydroxylations of 2-(1-hydroxyalkyl)-1,4,5,8(or 1,4,5,6,8)-tetra(or penta)methoxynaphthalenes and 2-(1-hydroxyalkyl)-1,4-dimethoxybenzenes at the 3-position were accomplished by a one-spot procedure.The same procedure has been found to be applicable to 2-(1-hydroxyalkyl)naphthalenes and (1-hydroxyalkyl)benzenes having no methoxy substituent.
- Tanoue, Yasuhiro,Terada, Akira,Seto, Iwao,Umezu, Yasuo,Tsuge, Otohiko
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p. 1221 - 1224
(2007/10/02)
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- Quassinoids. An Approach to the BCDE Rings of Bruceantin
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Synthesis of a model 28 for the BCDE rings of bruceantin via a BC -> BCE -> BCED ring strategy is presented.The sequence includes Diels-Alder reaction of methyl 3,5-hexadienoate 9 and quinone 8 derived from o-vanillyl alcohol, selenocyclization of hydroxy diester 22, and lactone formation to give the BCDE system 25.Manipulation on 25 showed the viability of its functional groups for further development in the synthetic strategy.
- Stevens, Robert V.,Vinogradoff, Anna P.
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p. 4056 - 4062
(2007/10/02)
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