- 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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- Selective synthesis of benzyl enol ethers of β-dicarbonyl compounds in basic condition and the application towards synthesis of naphthoquinones
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Selective synthesis of benzyl enol ether of β-tetronic acids and β-dicarbonyl compounds in basic condition was examined. Benzylation of α-methyl-β-tetronic acid with benzyl tosylate in the presence of potassium carbonate gave the corresponding benzyl enol ether exclusively. The reaction of β-tetronic acid and cyclic 1,3-diketones gave the O-benzyl adducts preferentially than the C,O-dibenzylated ones. Diels-Alder reaction of furan derived the benzyl enol ether of α-methyl-β-tetronic acid and benzyne furnished the functionalized napthoquinone derivatives.
- Katakawa, Kazuaki,Yonenaga, Dai,Terada, Tomoyo,Aida, Naoya,Sakamoto, Airi,Hoshino, Keishi,Kumamoto, Takuya
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p. 817 - 825
(2016/11/13)
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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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- METHOD FOR MAKING BIARYL COMPOUNDS, COMPOUNDS MADE BY THE METHOD, AND METHOD FOR THEIR USE
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Certain disclosed embodiments of the present invention concern a method for making biaryl compounds by combining a diene with a dienophile under reaction conditions that facilitate a Diels-Alder reaction. Certain embodiments are particularly directed to making a tetra-ortho-substituted biaryl compounds. The disclosed method may involve using novel dienes, dienophiles, or both. Similarly, certain of the biaryl compounds are novel compounds too. Additional disclosed embodiments concern a method for making useful compounds by first making a Diels-Alder adduct. The Diels-Alder adduct is then further modified or coupled to other compounds. The method can be used to make carbazoles, such as Siamenol. Disclosed biaryl compounds are useful for a number of applications, such as pharmacophores and organocatalysts.
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Page/Page column 195
(2009/01/23)
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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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- Diels - Alder approach for the construction of halogenated, o-nitro biaryl templates and application to the total synthesis of the anti-HIV agent siamenol
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(Chemical Equation Presented) A rapid Diels - Alder approach to halogenated biaryl templates is described. These biaryl templates are available in two steps from the corresponding aromatic aldehydes. The scope of subsequent Suzuki couplings on the biaryl chlorides is explored. Good tolerance for both electron-donating and electron-withdrawing groups in the coupling process can be achieved. Further functionalization of the biaryl templates is described. Hydrogenation of the nitro moiety with concomitant removal of the benzyl ether yields the o-anilino, o-phenolic polyaryls. Selective reduction of the nitro group can be accomplished. Alternatively, the benzyl ether can be selectively removed under Lewis acidic conditions. The utilization of the Diels - Alder adducts for the synthesis of a series of chlorinated carbazoles via the Cadogan cyclization is also demonstrated. Finally, application of this technology to the total synthesis of siamenol, an anti-HIV agent, is reported.
- Naffziger, Michael R.,Ashburn, Bradley O.,Perkins, Johanna R.,Carter, Rich G.
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p. 9857 - 9865
(2008/04/05)
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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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- Asymmetric allylic alkylation of cyclic vinylogous esters and thioesters by Pd-catalyzed decarboxylation of enol carbonate and β-ketoester substrates
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(Chemical Equation Presented) Excellent yields and enantioselectivities were achieved for the palladium-catalyzed asymmetric allylic alkylation of vinylogous thioesters. The close-to-neutral reaction conditions ensure that this reaction can tolerate a wide range of functionalities. Furthermore, this approach provides a convenient protocol for the synthesis of synthetically important α,α- and γ,γ-di-substituted cycloalkenones.
- Trost, Barry M.,Bream, Robert N.,Xu, Jiayi
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p. 3109 - 3112
(2007/10/03)
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- B(C6F5)3-catalyzed synthesis of β-keto enol ethers from β-diketones
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Efficient and practical synthesis of β-keto enol ethers from diketones catalyzed by B(C6F5)3 at room temperature has been described. Georg Thieme Verlag Stuttgart.
- Chandrasekhar,Srinivasa Rao,Ramakrishna Reddy
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p. 1471 - 1473
(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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- 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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- 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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- Resorcinol derivatives
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The present invention relates to the use of certain resorcinol derivatives as skin lightening agents.
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- Process for preparing resorcinol derivatives
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The present invention relates to an improved process for preparing 4-substituted resorcinol derivatives, and intermediate compounds useful in the preparation of such resorcinol derivatives.
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- Resorcinol derivatives
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The present invention relates to certain resorcinol derivatives and their use as skin lightening agents.
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- Resorcinol derivatives
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The present invention relates to the use of certain resorcinol derivatives as skin lightening agents.
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- ACTIVATION BY PdCl2(PhCN)2 OF THE ALCOHOLIC BENZYLIC FUNCTION TO NUCLEOPHILIC ALIPHATIC AS WELL AS ELECTROPHILIC AROMATIC SUBSTITUTIONS. A ONE STEP SYNTHESIS OF A CHROMANE STRUCTURE
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Benzylic alcohols react, by activation with PdCl2(PhCN)2, under mild conditions with alkanols and enols to give the corresponding benzylic ethers, and, under the same conditions, with aromatic substrates to give the corresponding phenylmethanes.As an example, a one-step synthesis of a chromane structure is reported.
- Mincione, Enrico,Bovicelli, Paolo
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p. 437 - 440
(2007/10/02)
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