- Remarkable catalytic activity of silica nanoparticle in the bis-Michael addition of active methylene compounds to conjugated alkenes
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We have demonstrated the remarkable catalytic activity of silica nanoparticles (NPs) in the unusual bis-Michael addition of active methylene compounds to conjugated alkenes at room temperature. The catalyst silica NPs were reused up to seven runs without appreciable loss of catalytic activity.
- Banerjee, Subhash,Santra, Swadeshmukul
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p. 2037 - 2040
(2009/09/05)
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- Ionic liquid as catalyst and solvent: the remarkable effect of a basic ionic liquid, [bmIm]OH on Michael addition and alkylation of active methylene compounds
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A basic ionic liquid, 1-methyl-3-butylimidazolium hydroxide, [bmIm]OH, catalyzes the Michael addition of active methylene compounds to conjugated ketones, carboxylic esters and nitriles. It further catalyzes the addition of thiols to α,β-acetylenic ketones and alkylation of 1,3-dicarbonyl and -dicyano compounds. The Michael addition to α,β-unsaturated ketones proceeds in the usual way, giving the monoaddition products, whereas addition to α,β-unsaturated esters and nitriles leads exclusively to the bis-addition products. The α,β-acetylenic ketones undergo double conjugate addition with thiols producing β-keto 1,3-dithio-derivatives. In the alkylation reaction the acyclic 1,3-diketones are monoalkylated, whereas cyclic ketones undergo dialkylation under identical conditions. All these reactions were carried out without any organic solvent. The ionic liquid can also be recycled.
- Ranu, Brindaban C.,Banerjee, Subhash,Jana, Ranjan
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p. 776 - 782
(2007/10/03)
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- Ionic liquid as catalyst and reaction medium. The dramatic influence of a task-specific ionic liquid, [bmIm]OH, in Michael addition of active methylene compounds to conjugated ketones, carboxylic esters, and nitriles
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(Chemical Equation Presented) A task-specific ionic liquid, [bmIm]OH, has been introduced as a catalyst and as a reaction medium in Michael addition. Very interestingly, although the addition to α,β-unsaturated ketones proceeds in the usual way, giving the monoaddition products, this ionic liquid always drives the reaction of open-chain 1,3-dicarbonyl compounds with α,β-unsaturated esters and nitriles toward bis-addition to produce exclusively bis-adducts in one stroke.
- Ranu, Brindaban C.,Banerjee, Subhash
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p. 3049 - 3052
(2007/10/03)
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- Solid-supported Robinson annulation under microwave irradiation.
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Robinson annulation on alumina occurred efficiently on heating with microwave irradiation.
- Takatori, Kazuhiko,Nakayama, Masayasu,Futaishi, Naoko,Yamada, Saori,Hirayama, Shinobu,Kajiwara, Masahiro
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p. 455 - 457
(2007/10/03)
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- Synthesis and reactivity of Michael adducts of cyclic β-ketoesters enolates with electrophilic acetylenes
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The enolates of cyclic β-ketoesters react with electrophilic acetylenes to give the corresponding Michael adducts in good yields when the reaction is performed in acetone in the presence of catalytic amounts of K2CO3. The Michael adducts resulting from ethynylmethylketone, when refluxed in toluene in the presence of catalytic amount of pTsOH, undergo an intramolecular aldol reaction leading mainly to bicyclo [n. 3.1]alkadienones besides Robinson annulation products.
- Miesch, Michel,Mislin, Gaetan,Franck-Neumann, Michel
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p. 6873 - 6876
(2007/10/03)
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- HIGHLY STEREOSELECTIVE SYNTHESIS OF SUBSTITUTED HYDRINDANES RELATED TO THE ANTIEPILEPTIC DRUG TOPIRAMATE
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Multistep syntheses of two "carbocyclic" analogues 2 and 3 of topiramate (1) were effected with excellent stereocontrol.Two key reactions employed were: deoxygenation-rearrangement of an enone with p-tosylhydrazine and catecholborane (14 --> 15 and 5 -->
- Greco, Michael N.,Maryanoff, Bruce E.
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p. 5009 - 5012
(2007/10/02)
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- The Rearrangements of the Nitrones of Simple Cyclic Conjugated Ketones
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The ring expansions of N-methyl nitrones formed from cyclic conjugated ketones have been investigated.Low yields of cyclic amides were obtained.In general, the best conditions for the rearrangement involved using p-toluenesulfonyl chloride and polyphosphoric acid in tetrahydrofuran.The parent ketone and, in some cases, an N-aryl sulfonamide were also obtained; mechanisms for their formation are discussed.
- Prager, Rolf H.,Raner, Kevin D.,Ward, A. David
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p. 381 - 387
(2007/10/02)
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