- Copper(ii)-catalyzed and acid-promoted highly regioselective oxidation of tautomerizable C(sp3)-H bonds adjacent to 3,4-dihydroisoquinolines using air (O2) as a clean oxidant
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A mild, efficient and eco-friendly method for the oxidation of 1-Bn-DHIQs to 1-Bz-DHIQs without concomitant excessive oxidation of 1-Bz-DHIQs to 1-Bz-IQs is very important for the syntheses of 1-Bz-DHIQ alkaloids and analogues. In this article, we developed a novel Cu(ii)-catalyzed and acid-promoted highly regioselective oxidation of tautomerizable C(sp3)-H bonds adjacent to the C-1 positions of various 1-Bn-DHIQs. It was observed that when 0.2 equiv. of Cu(OAc)2·2H2O was used as the catalyst, 3.0 equiv. of AcOH was used as the additive and air (O2) was used as a clean oxidant, various 1-Bn-DHIQs could be efficiently oxidized to corresponding 1-Bz-DHIQs at 25 °C in DMSO. Especially, almost no concomitant excessive oxidation of 1-Bz-DHIQs to 1-Bz-IQs was observed during the above reaction. In addition, this method was successfully applied in the first total synthesis of the alkaloid canelillinoxine.
- Fan, Qi-Qi,He, Yun-Gang,Huang, Yong-Kang,Luo, Yong-Qiang,Shi, Xiao-Xin,Zheng, Bo,Zhu, Xing-Liang
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p. 29702 - 29710
(2021/10/08)
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- Total Synthesis of (-)-Melanthioidine by Copper-Mediated Cyclodimerization
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An efficient asymmetric total synthesis of the dimeric macrocyclic diaryl ether phenethyltetrahydroisoquinoline alkaloid (-)-melanthiodine is reported. Key steps of the synthesis include an efficient Noyori asymmetric transfer hydrogenation to access the enantioenriched phenethyltetrahydroisoquinoline monomeric subunit and a copper-mediated cyclodimerization to form the two diaryl ether linkages with concomitant macrocyclization.
- Wang, Jianjun,Evano, Gwilherm
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supporting information
p. 3542 - 3545
(2016/08/16)
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- Ethylenediamine: A highly effective catalyst for one-pot synthesis of aryl nitroalkenes via henry reaction and dehydration
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Ethylenediamine (H2NCH2CH2NH2) was found to be a highly effective catalyst for the condensation of aryl aldehydes with nitromethane (or nitroethane). When 1%-2% (mol%) of ethylenediamine was used as the catalyst, the one-pot reaction of aryl aldehydes with nitromethane (or nitroethane) by refluxing for 3-10 h efficiently afforded various arylnitroalkenes 1a-1y in 85%-97% yields. Ethylenediamine (H 2NCH2CH2NH2) was found to be a highly effective catalyst for the condensation of aryl aldehydes with nitromethane (or nitroethane). When 1-2 mol% of ethylenediamine was used as the catalyst, the one-pot reaction of aryl aldehydes with nitromethane (or nitroethane) by refluxing for 3-10 h efficiently afforded various aryl nitroalkenes 1a-1y in 85%-97% yields. Copyright
- Yang, Jianxin,Dong, Jing,Lue, Xia,Zhang, Qiang,Ding, Wei,Shi, Xiaoxin
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p. 2827 - 2833
(2013/08/23)
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- Synthesis of vinylphosphonates and its first exploration of bioactivity
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Phosphonation of β-nitro-alkene with triethyl phosphite was achieved under microwave irradiation using CH2Cl2 as the solvent in the absence of catalyst with moderate to high yields (up to 90%). This method of formation of carbonphosphor bonds is simple, mild, convenient and effective. Synchronously, a number of vinylphosphonates derivatives were synthesized and evaluated biologically preliminary.
- Li, Sheng-Nan,Xu, Lan-Ting,Chenb, Yue,Lia, Ju-Lian,He, Ling
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experimental part
p. 416 - 422
(2012/05/04)
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- E-Combretastatin and E-resveratrol structural modifications: Antimicrobial and cancer cell growth inhibitory β-E-nitrostyrenes
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As part of a broad-based SAR investigation of E-resveratrol (strong sirtuin activator and antineoplastic) and the anticancer vascular-targeting combretastatin-type stilbenes, a series of twenty-three β-E-nitrostyrenes was synthesized in order to evaluate potential antineoplastic, antitubulin, and antimicrobial activities. The β-E-nitrostyrenes evaluated ranged from monosubstituted phenols to trimethoxy and 3-methoxy-4,5-methylenedioxy derivatives. Two of the β-nitrostyrenes were synthesized as water-soluble sodium phosphate derivatives (4t, 4v). All except four (4r, 4s, 4t, 4u) of the series significantly inhibited a minipanel of human cancer cell lines. All but eight led to an IC50 of 10 μM for inhibition of tubulin polymerization, and all except three (4l, 4t, 4v) displayed antimicrobial activity.
- Pettit, Robin K.,Pettit, George R.,Hamel, Ernest,Hogan, Fiona,Moser, Bryan R.,Wolf, Sonja,Pon, Sandy,Chapuis, Jean-Charles,Schmidt, Jean M.
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experimental part
p. 6606 - 6612
(2009/12/06)
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- Isolation and synthesis of analgesic and anti-inflammatory compounds from Ochna squarrosa L.
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Two new furanoflavonoids (1, 2), one new chalcone dimer (3) along with six known compounds, chrysophanol, 5-O-methyl squarrosin, 5-methoxy furano[4″,5″,6,7]flavone, calodenone, lophirone A and lophirone H were isolated from the ethyl acetate-soluble fraction of methanol extract of root bark of Ochna squarrosa. Chrysophanol, calodenone, lophirone A and lophirone H were isolated from this plant for the first time. The structures of all the isolated compounds were confirmed by 1D and 2D spectroscopic data. These compounds were tested for analgesic and anti-inflammatory activity. All the new compounds showed good analgesic and anti-inflammatory activity. A simple and facile method for the cleavage of benzyl ethers using I2 in trigol is also reported.
- Anuradha,Srinivas, Pullela V.,Ranga Rao,Manjulatha,Purohit, Muralidhar G.,Madhusudana Rao
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p. 6820 - 6826
(2007/10/03)
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- Solid-supported acids for debenzylation of aryl benzyl ethers
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Solid-supported acids have been investigated for aromatic debenzylation reactions. Stoichiometric amounts of solid-supported acids in refluxing toluene with or without 4 equiv of methanol effectively provided the desired aromatic debenzylation products of various systems in moderate to excellent yields (up to 98%).
- Petchmanee, Thaninee,Ploypradith, Poonsakdi,Ruchirawat, Somsak
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p. 2892 - 2895
(2007/10/03)
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- β-Nitrostyrene derivatives as potential antibacterial agents: A structure-property-activity relationship study
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A multidisciplinary project was developed, combining the synthesis of a series of β-nitrostyrene derivatives and the determination of their physicochemical parameters (redox potentials, partition coefficients), to the evaluation of the corresponding antibacterial activity. A complete conformational analysis was also performed, in order to get relevant structural information. Subsequently, a structure-property-activity (SPAR) approach was applied, through linear regression analysis, aiming at obtaining a putative correlation between the physicochemical parameters of the compounds investigated and their antibacterial activity (both against standard strains and clinical isolates). The β-nitrostyrene compounds displayed a lower activity towards all the tested bacteria relative to the β-methyl-β-nitrostyrene analogues. This was observed particularly for the 3-hydroxy-4-methoxy-β-methyl-β-nitrostyrene (IVb) against the Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium). The SPAR results revealed the existence of a clear correlation between the redox potentials and the antibacterial activity of the series of β-nitrostyrene derivatives under study.
- Milhazes, Nuno,Calheiros, Rita,Marques, M. Paula M.,Garrido, Jorge,Cordeiro, M. Natália D.S.,Rodrigues, Cátia,Quinteira, Sandra,Novais, Carla,Peixe, Luísa,Borges, Fernanda
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p. 4078 - 4088
(2007/10/03)
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- Nitration of cinnamic acids using cerium (IV) ammonium nitrate immobilized on silica
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Treatment of cinnamic acids with cerium (IV) ammonium nitrate supported on silica (CAN/SiO2) was used to synthesize nitro derivative and ipso substitution products. The position of the substituents defines the type and the yields of the product
- Messere, Anna,Gentili, Alessandra,Garella, Isidoro,Temussi, Fabio,Di Blasio, Benedetto,Fiorentino, Antonio
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p. 3317 - 3324
(2007/10/03)
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- Heterogeneous catalysts in the preparation of 2-aryl-1,3-dinitropropanes from β-nitrostyrenes or benzaldehydes
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The use of heterogeneous basic catalysts (KF, NaHCO3) in the preparation of 2-Aryl-1,3-dinitropropanes from β-nitrostyrenes or benzaldehydes is described, with one example followed kinetically by HPLC analysis of aliquots of the reaction.
- Fierro,Rezende,Sepulveda-Boza,Reyes-Parada,Cassels
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p. 294 - 296
(2007/10/03)
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- Morpholine adsorbed on silica gel: A novel and mild basic catalyst for the synthesis of α,β-unsaturated nitroalkenes
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Syntheses of α,β-unsaturated nitroalkenes have been carried out under mild condition using morpholine adsorbed on silica gel as a novel catalyst.
- Bandgar, Babasaheb P.,Uppalla, Lav S.,Sadavarte, Vaibhav S.
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p. 949 - 952
(2007/10/03)
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- The ultrasound promoted Knoevenagel condensation of aromatic aldehydes
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Application of ultrasound has been found to greatly assist the Knoevenagel aldol condensation reaction of activated methylenes with aromatic aldehydes under mild conditions. The outcome of the ultrasound-promoted reaction depends upon the electronic nature of the aromatic aldehyde, the solvent employed and the addition of acids, bases or ammonium salts.
- McNulty, James,Steere, Jennifer A.,Wolf, Sonja
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p. 8013 - 8016
(2007/10/03)
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- Microwave-Assisted Henry Reaction: Solventless Synthesis of Conjugated Nitroalkenes
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In a solventless system and under microwave irradiation, nitroalkanes react with arylaldehydes in the presence of a catalytic amount of ammonium acetate to afford, in one step, conjugated nitroalkenes without the isolation of intermediary β-nitro alcohols. - Key Words: Arylaldehydes; Nitroalkanes; Ammonium acetate; Conjugated nitroalkenes; Henry reaction; Microwave irradiation
- Varma, Rajender S.,Dahiya, Rajender,Kumar, Sudhir
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p. 5131 - 5134
(2007/10/03)
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