4604-49-3Relevant academic research and scientific papers
Intermolecular domino Michael/aldol reactions of α,β-unsaturated esters, aromatic aldehydes, and various nucleophiles promoted with a catalytic amount of a guanidine base in DMSO
Matsuo, Jun-ichi,Morita, Shunya,Yoshimura, Tomoyuki
, (2021/07/28)
In DMSO, a catalytic amount of Barton's base (2-t-butyl-1,1,3,3-tetramethylguanidine, BTMG) effectively catalyzed intermolecular three-component reactions of α,β-unsaturated esters, aldehydes, and carbon-, sulfur-, or nitrogen-pronucleophiles to give three-component addition products with the formation of two new σ-bonds: pronucleophiles and aldehydes reacted with α,β-unsaturated esters at their β-positions and α-positions, respectively. Mechanism studies suggested that these reactions proceeded by the first intermolecular Michael addition of anionic nucleophiles that were formed from pronucleophiles with a catalytic amount of BTMG, followed by intermolecular aldol reactions of transient ester enolates even in the presence of more than stoichiometric amounts of acidic pronucleophiles. High nucleophilicity over Br?nsted basicity of transient enolates in polar solvents was observed for transient ester enolates rather than ketone enolates.
Poly(N-vinylimidazole) as efficient recyclable catalyst for the Michael addition of CH-acids to electron deficient alkenes in water
Tarasenko, E. A.,Beletskaya, I. P.,Tyurin, V. S.,Lamaty, F.
, p. 2613 - 2616,4 (2020/09/16)
Efficiency of poly(N-vinylimidazole) as the basic recyclable catalyst for the Michael addition of CH-acids to acrylonitrile, methyl acrylate, methyl vinyl ketone and methyl vinyl sulfone in water at ambient temperature was studied. In these reactions, formation of both 1 : 1 and 1 : 2 adducts is possible.
2-Substituted nitrones and isomeric hydroxylamines - obtained via aluminium amalgam reduction of nitro nitriles and ketones-a new access to convenient intermediates for nitroso carbonyl compounds preparation
Grela, Karol,Konopski, Leszek
body text, p. 3608 - 3613 (2010/07/05)
Substituted five-membered cyclic nitrones (pyrroline N-oxides) have been obtained in good to high yields from tertiary γ-nitro ketones and nitriles employing aluminium amalgam as a reducing agent in moist diethyl ether or THF. Attempts to obtain cyclic amino nitrones from α- or β-nitro nitriles failed and only the corresponding hydroxylamines have been isolated. Both nitrones and hydroxylamines have been used for synthesis of tertiary C-nitroso nitriles or ketones.
Bifunctional heterogeneous catalysis of silica-alumina-supported tertiary amines with controlled acid-base interactions for efficient 1,4-addition reactions
Motokura, Ken,Tanaka, Satoka,Tada, Mizuki,Iwasawa, Yasuhiro
experimental part, p. 10871 - 10879 (2010/04/05)
We report the first tunable bifunctional surface of silica-aluminasupported tertiary amines (SA-NEt2) active for catalytic 1,4-addition reactions of nitroalkanes and thiols to electron-deficient alkenes. The 1,4-addition reaction of nitroalkanes to electron-deficient alkenes is one of the most useful carbon-carbon bond-forming reactions and applicable toward a wide range of organic syntheses. The reaction between nitroethane and methyl vinyl ketone scarcely proceeded with either SA or homogeneous amines, and a mixture of SA and amines showed very low catalytic activity. In addition, undesirable side reactions occurred in the case of a strong base like sodium ethoxide employed as a catalytic reagent. Only the present SA-supported amine (SA-NEt2) catalyst enabled selective formation of a double-alkylated product without promotions of side reactions such as an intramolecular cyclization reaction. The heterogeneous SA-NEt2 catalyst was easily recovered from the reaction mixture by simple filtration and reusable with retention of its catalytic activity and selectivity. Fur-thermore, the SA-NEt2 catalyst system was applicable to the addition reaction of other nitroalkanes and thiols to various electron-deficient alkenes. The solid-state magic-angle spinning (MAS) NMR spectroscopic analyses, including variable-contact-time 13C cross-polarization (CP)/MAS NMR spectroscopy, revealed that acid-base interactions between surface acid sites and immobilized amines can be controlled by pretreatment of SA at different temperatures. The catalytic activities for these addition reactions were strongly affected by the surface acid-base interactions. 2009 Wiley-VCH Verlag GmbH & Co. KGaA.
Oxalic acid catalyzed reaction between dithioacetals and acetals. A simple and eco-friendly method for a conversion of a dithioacetal to a carbonyl compound
Miyake, Hideyoshi,Nakao, Yuichi,Sasaki, Mitsuru
, p. 6247 - 6250 (2007/10/03)
Oxalic acid catalyzes a reaction between dithioacetals and acetals. This reaction is useful in a new and eco-friendly method to convert dithioacetals to carbonyl compounds.
Use of heterogeneous catalyst KG-60-NEt2 in Michael and Henry reactions involving nitroalkanes
Ballini, Roberto,Bosica, Giovanna,Livi, Damiana,Palmieri, Alessandro,Maggi, Raimondo,Sartori, Giovanni
, p. 2271 - 2273 (2007/10/03)
The N,N-diethylpropylamine supported on amorphous silica (KG-60-NEt2) catalyses the formation of carbon-carbon bonds by nitroalkanes through both the nitroaldol (Henry) and Michael reactions. The catalyst shows general utility with a variety of electrophilic acceptors. Moreover, the catalyst can be reused for two further cycles without loss of the activity.
P(RNCH2CH2)3N: Efficient 1,4-addition catalysts
Kisanga, Philip B.,Ilankumaran, Palanichamy,Fetterly, Brandon M.,Verkade, John G.
, p. 3555 - 3560 (2007/10/03)
The 1,4-addition of primary alcohols, higher nitroalkanes, and a Schiff's base of an α-amino ester to α,β-unsaturated substrates produces the corresponding products in moderate to excellent yields when carried out at -63 to 70°C in the presence of catalytic amounts of the nonionic strong bases P(RNCH2CH2)3N (R = Me, i-Pr, i-Bu) in isobutyronitrile. Diastereoselectivity for the anti form of the product is high in the case of the Schiff's base in the absence of lithium ion. These catalysts are easily removed from the product by either column filtration through silica gel or via aqueous workup.
Electrochemical and esr spin trap studies of a new iron tetra- catecholamide complex
Cheraiti,Brik,Keita,Nadjo,Gaudemer
, p. 2315 - 2320 (2007/10/03)
A new siderophore, N5,N6-thiodipropanoyl-bis[N1,N10-bis(2,3-dihydroxy benzoyl-spermidine)]-Fe (III) complex or H2LFe has been synthesised. The reaction of the reduced form of this complex with dioxygen has been investigated through electrochemical study and revealed the formation of a new species assumed to be H2O2. This species has been confirmed by esr spectroscopy using the diamagnetic compound 5-deutero-2,2,5- trimethylpyrrolidine-1-hydroxyl as spin trap. The resulting persistent radical is 5-deutero-2,2,5-trimethylpyrrolidine-1-yloxy (a(N) = 16.58 G, a(D) = 3.49 G).
