- Rapid and Multigram Synthesis of Vinylogous Esters under Continuous Flow: An Access to Transetherification and Reverse Reaction of Vinylogous Esters
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An environmentally benign approach for the synthesis of vinylogous esters from 1,3-diketone and its reverse reaction under continuous-flow has been developed with alcohols in the presence of inexpensive Amberlyst-15 as a catalyst. This methodology is highly selective and general for a range of cyclic 1,3-dicarbonyl compounds which gives a library of linear alkylated and arylated vinylogous esters in good to excellent yield under solvent and metal free condition. Furthermore, the long-time experiment in a continuous-flow up to 40 h afforded 8.0 g of the vinylogous ester with turnover number (TON) = 28.6 and turnover frequency (TOF) = 0.715 h-1 using Amberlyst-15 as a catalyst. Furthermore, a continuous-flow sequential transetherification of vinylogous esters with various alcohols has been achieved in high yield. Reversibly, this vinylogous ester was deprotected or hydrolyzed into ketone using environmentally benign water as a solvent and Amberlyst-15 as a catalyst under continuous-flow process.
- Mohanta, Nirmala,Chaudhari, Moreshwar B.,Digrawal, Naveen Kumar,Gnanaprakasam, Boopathy
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p. 1034 - 1045
(2019/05/24)
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- Reversible chemoselective transetherification of vinylogous esters using Fe-catalyst under additive free conditions
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An additive/Br?nsted acid/base free, highly efficient and chemoselective transetherification of electron deficient vinylogous esters and water mediated de-alkylation using an earth-abundant Fe-catalyst under very mild reaction conditions is described. This reaction is highly selective to primary alcohols over secondary alcohols, has good functional group tolerance, is scalable to gram scale and a purification free sequential transetherification in a continuous flow mode is demonstrated.
- Parvathalu, Nenavath,Agalave, Sandip G.,Mohanta, Nirmala,Gnanaprakasam, Boopathy
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p. 3258 - 3266
(2019/03/26)
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- Cyclization of 5-hexynoic acid to 3-alkoxy-2-cyclohexenones
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The one-pot cyclization of 5-hexynoic acid to produce 3-alkoxy-2- cyclohexenones proceeds in good yields (58-90%). 3-Hexynoic acid was converted to its acyl chloride with the aid of oxalyl chloride and was cyclized to 3-chloro-2-cyclohexenone upon addition of indium(III) chloride. Subsequent addition of alcohol nucleophiles led to the desired 3-alkoxy-2-cyclohexenones.
- Hylden, Anne T.,Uzelac, Eric J.,Ostojic, Zeljko,Wu, Ting-Ting,Sacry, Keely L.,Sacry, Krista L.,Xi, Lin,Jones, T. Nicholas
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experimental part
p. 1323 - 1326
(2011/11/06)
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- Recombination of diterpenoid structure units: Synthesis of antitumor amides bearing functionalized bicyclo[3.2.1]octane ring
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In this work, 23 new amides (14-36) bearing a representative diterpenoid structure unit, the functionalized bicyclo[3.2.1]octane ring, have been synthesized and its antitumor potential is studied. In vitro studies demonstrate that a number of amides with the bicyclo[3.2.1]oct-3-en-2-one subunit are active against HL-60, SMMC-7721, A-549, SK-BR-3, and PANC-1 tumor cell lines. The hybrid derivative, compound 20, was found to be the most potent compound (IC50 = 1.05 μM against HL-60) and more active than cisplatin (DDP), the positive control. Additionally, compound 20 exhibited broad spectrum in vitro anticancer activity with IC50 values of 1.1-4.3 μM against the five tested cancer cell lines.
- Mao, Zewei,Li, Yan,Chen, Jingbo,Wang, Yuanyuan,Zhang, Hongbin
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scheme or table
p. 4116 - 4119
(2010/08/07)
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- Iron(III) tosylate in the preparation of dimethyl and diethyl acetals from ketones and β-keto enol ethers from cyclic β-diketones
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An efficient method for conversion of ketones to their corresponding dimethyl and diethyl acetals and of cyclic β-diketones into β-keto enol ethers using Fe(OTs)3 as a catalyst is described. Copyright Taylor & Francis Group, LLC.
- Mansilla, Horacio,Afonso, Maria M.
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p. 2607 - 2618
(2008/12/22)
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- Ytterbium triflate catalyzed synthesis of β-keto enol ethers
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β-Keto enol ethers have been synthesized in very good yield in solvent-free conditions from differently substituted alcohols and β-diketones in the presence of Yb(OTf)3 as catalyst. The method is applicable to both cyclic and acyclic β-diketones with only slight differences in the experimental procedure.
- Curini, Massimo,Epifano, Francesco,Genovese, Salvatore
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p. 4697 - 4700
(2007/10/03)
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- An efficient conversion of β-diketones into β-keto enol ethers with P2O5/SiO2 under solvent-free conditions
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P2O5/SiO2 was found to be an efficient reagent for converting cyclic-β-diketones into their corresponding β-keto enol ethers at room temperature under solvent-free conditions.
- Cui, Zhen-Shui,Zhang, Zhan-Hui,Liu, Shu-Fen
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p. 390 - 392
(2007/10/03)
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- Cerium(IV) ammonium nitrate-catalyzed synthesis of β-keto enol ethers from cyclic β-diketones and their deprotection
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A mild and efficient method for etherification of cyclic β-diketones with alcohols has been developed using a catalytic amount of cerium(IV) ammonium nitrate at room temperature to afford the corresponding β-keto enol ethers in good to excellent yields. The deprotections of enol ethers in water-acetonitrile (1:1) using a catalytic amount (10 mol %) of cerium(IV) ammonium nitrate have also been achieved. Copyright
- Banerjee, Biplab,Mandal, Samir Kumar,Roy, Subhas Chandra
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- Microwave assisted rapid synthesis of 3-alkoxy-2-cyclohexen-1-ones from 1,3-cyclohexanedione
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Synthesis of 3-alkoxy-2-cyclohexen-1-ones from 1,3-cyclohexanedione with various alcohols has been achieved under microwave irradiation conditions within 7 min.
- Murugan,Reddy
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p. 1512 - 1514
(2007/10/03)
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- Solvent free rapid synthesis of 3-alkoxycyclohex-2-en-1-one from 1,3-cyclohexanedione promoted by indium(in) chloride/silica gel
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A convenient and environmentally friendly method for the synthesis of 3-alkoxycyclohex-2-en-1-one 1 from cyclohexane-1,3-dioneonthe surface of silica gel impregnated with indium(III) chloride under microwave irradiation without any solvent has been reported CSIRO 2005.
- Murugan,Kamakshi,Reddy, Boreddy S. R.
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p. 228 - 230
(2008/02/04)
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- Iodine-catalyzed synthesis of β-keto enol ethers
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The use of iodine, as a catalyst for the synthesis of β-keto enol ethers at room temperature is reported. The use of iodine, as a catalyst for the synthesis of β-keto enol ethers at room temperature is reported.
- Bhosale, Rajesh S.,Bhosale, Sidhanath V.,Bhosale, Sheshanath V.,Wang, Tianyu,Zubaidha
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p. 7187 - 7188
(2007/10/03)
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- A New Approach to Morphinans: Total Synthesis of O-Methylpallidinine
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We have devised a general method for the synthesis of 4a-aryloctahydroisoquinolines related to morphine and have shown how these compounds may be used in a route to morphinan alkaloids.The key step in this route involves the addition of diazomethane to a 4a-aryloctahydroisoquinolinium salt, followed by spontaneous cyclization to the morphinan.Studies of this step indicate that it is not compatible with the presence of an alkoxyl group at C4 of the aryl ring.The value of this method has been demonstrated in the context of stereospecific total synthesis of O-methylpallidinine.
- McMurry, John E.,Farina, Vittorio,Scott, William J.,Davidson, Alan H.,Summers, David R.,Shenvi, Ashok
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p. 3803 - 3812
(2007/10/02)
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- Stereospecific and Stereoselective Reactions. V. Alkylation of Active Methylene Compounds by the Use of Alcohols, Diethyl Azodicarboxylate, and Triphenylphosphine
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The reagent formed by the reaction of diethyl azodicarboxylate (1) and triphenylphosphine (2) reacted with alcohols and ethyl cyanoacetate (6) to give alkylated products in 30 - 80percent yields.When ethyl acetoacetate, 1,3-1,3-coclopentanedione, or 1,3-cyclohexanedione was used in place of 6, the corresponding O-alkylated products were obtained.The reaction of either (S)-(-)-ethyl lactate or (S)-(-)-ethyl 2-hydroxy-3-phenylpropionate with 1, 2, and 6, followed by hydrolysis resulted in the formation of (S)-(-)-methylsuccinic acid or (S)-(-)-benzylsuccinic acid.The results indicate that nearly complete inversion of the configuration takes place in the alkylation step.
- Kurihara, Toshio,Sugizaki, Masaru,Kime, Itaru,Wada, Makoto,Mitsunobu, Oyo
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p. 2107 - 2112
(2007/10/02)
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