102-96-5Relevant academic research and scientific papers
Humic substances as catalysts m condensation reactions
Klavins, Maris,Dipane, Judite,Babre, Kristine
, p. 737 - 742 (2001)
Humic substances (HS) demonstrate appreciable impact on the rate of the condensation reactions as shown in the example of the reaction between hydrazine and 4-(dimethylamino)-benzaldhyde in an aquatic environment. The catalytic activity of HS has also been demonstrated in Knoevenagel and Claisen-Schmidt reactions for condensation of carbonyl compounds with CH acids. The aquatic fulvic acids are the most active in these reactions. The velocity of the studied reactions also depends on pH, temperature, the concentration and origin of HS used. A possible micellar and acid-base catalysis mechanism in aquatic media has been suggested.
Porous Boron Nitride as a Weak Solid Base Catalyst
Nakamura, Shohei,Takagaki, Atsushi,Watanabe, Motonori,Yamada, Kanta,Yoshida, Masaaki,Ishihara, Tatsumi
, p. 6033 - 6039 (2020)
Porous boron nitride was synthesized by pyrolysis from boric acid and urea mixed in varying molar ratios. The boron nitride prepared had high surface areas ranging from 376 to 647 m2 g?1 with both microporous and mesoporous structures. The sample prepared with a urea-to-boric acid molar ratio of 5 exhibited the highest pore volume with the highest surface area of mesopores. Boron-K edge X-ray absorption fine structure spectroscopy revealed that the surface structure consisted of BN3 sites along with BN2O, BNO2, and BO3 sites. Fourier transform infrared (FTIR) spectroscopy indicated the formation of amino and hydroxyl groups on the surface. Analysis using color indicator reagents and deuterated chloroform-adsorbed FTIR results indicated that the porous boron nitride had very weak base sites of strength +7.2>H?≥+6.3. Porous boron nitride exhibited a high activity for the nitroaldol reaction with a high selectivity for nitroalkene (>97 %). A good correlation was observed between the catalytic activity of the boron nitride catalysts and their porous structures.
Water-controlled nitro-oximation of alkenes under catalyst-free conditions
Tang, Lin,Yang, Zhen,Chang, Xueping,Zou, Guodong,Zhou, Yuqiang,Rao, Weihao,Ma, Xiantao,Zhao, Geng
, p. 4272 - 4275 (2018)
A convenient and precise nitration and oximation of alkenes with tert-butyl nitrite has been reported, yielding α-nitro ketoximes in satisfactory yields with broad substrate generality and excellent stereoselectivity under mild conditions. Experiments indicate that tert-butyl nitrite serves as both NO and NO2 sources and water plays a key role in this difunctionalization reaction.
Cu(II) homogeneous and heterogeneous catalysts for the asymmetric Henry reaction
Jones, Matthew D.,Cooper, Christine J.,Mahon, Mary F.,Raithby, Paul. R.,Apperley, David,Wolowska, Joanna,Collison, David
, p. 8 - 14 (2010)
New homogeneous Cu(II) complexes have been prepared, fully characterised and tested for the asymmetric Henry reaction. Heterogeneous Cu(II) catalysts have been synthesised for comparison purposes.
Diastereoselective synthesis of polysubstituted cyclopentanols and cyclopentenes containing stereogenic centers via domino Michael/cyclization reaction
Ahadi,Naghdiani,Balalaie,Rominger
, p. 6860 - 6866 (2015)
A highly efficient domino Michael/cyclization reaction was developed for the synthesis of cyclopentanols and cyclopentenes with four and three stereogenic centers that were generated in one-pot reaction conditions with high diastereoselectivity. The reactions proceeded through a one-pot three-component reaction of β-nitrostyrenes, malononitrile and phenacyl bromide derivatives in basic media at room temperature.
A simple O-sulfated thiohydroximate molecule to be the first micromolar range myrosinase inhibitor
Cerniauskaite, Deimante,Gallienne, Estelle,Karciauskaite, Henreta,Farinha, Andrea S.F.,Rousseau, Jolanta,Armand, Sylvie,Tatibou?t, Arnaud,Sackus, Algirdas,Rollin, Patrick
, p. 3302 - 3305 (2009)
New non-hydrolyzable analogues of glucosinolates have been prepared. Myrosinase inhibition was observed with modified aglycon moieties, even bulky phenothiazine analogue 6 gave reasonable inhibition. The simplest structure 8 derived from dimethylaminoethanethiol has shown to be the most potent inhibitor with an IC50 of 3.32 μM.
Direct synthesis and application of bridged diamino-functionalized periodic mesoporous organosilicas with high nitrogen contents
Zhu, Feng-Xia,Zhao, Pu-Su,Sun, Xiao-Jun,An, Li-Tao,Deng, Yong,Wu, Jia-Min
, p. 70 - 75 (2017)
Bridged diamino-functionalized periodic mesoporous organosilicas [BD-PMO(Et), Et = ethyl] materials were synthesized directly by co-condensation of 2-bis (triethoxysilyl)ethane (BTEE) and 1,4-bis[3-(tirmethoxysilyl)-propyl]ethylenediamino (BTMSEN) under acidic conditions with pluronic triblock copolymer P123 as a template. The nitrogen content in BD-PMO(Et) could be adjusted up to 40% without disturbing the ordered mesoporous structure. These materials were proved to be effective heterogeneous catalysts for the liquid-phase reactions such as Knoevenagel and Henry condensations as well as in the intermolecular cross-double-Michael addition reaction between α-methyl-β-nitrostyrene and α, β-unsaturated ketone. They exhibited comparable catalytic activities with homogeneous catalyst piperazine and can be reused for several times without any negative environmental impact.
Mild and Regioselective Three-component Heteroarylation-Nitration of Alkenes with Imidazo[1,2-a]pyridines and tert-Butyl Nitrite
Liu, Ping,Sun, Peipei,Xie, Shentong,Zhang, Jie
, (2020)
An efficient and regioselective three-component heteroarylation-nitration of alkenes with imidazo[1,2-a]pyridines and tert-butyl nitrite has been developed. The process tolerants a variety of functional groups under mild conditions in the absence of catalysts and additives to give nitro functionalized imidazo[1,2-a]pyridine derivatives in moderate to good yields. The reaction is also applicable for some other aza-heterocycles. (Figure presented.).
Preparation and synergetic catalytic effects of amino-functionalized MCM-41 catalysts
Lang, Wanzhong,Su, Bo,Guo, Yajun,Chu, Lianfeng
, p. 1167 - 1174 (2012)
Four amine functionalized mesoporous catalysts were synthesized by grafting primary, dualistic and two secondary amines onto the channel walls of mesoporous silica, MCM-41. We examined the effects of organoamine loading amount on the acid-base synergism of the catalysts in the self-condensation reaction of n-butanal, a Knoevenagel condensation and a Henry reaction. We observed the balance of the amine and residual silanol amounts is crucial to the catalytic performances of the functionalized mesoporous catalysts. An optimum organoamine loading amount exists, which is dependent on the organoamine type. There is little difference in the optimum organoamine loading amount between different reactions. The secondary organoamine functionalized MCM-41 exhibits the best catalytic performance in the experimental range.
Facile and efficient michael addition of indole to nitroolefins catalyzed by zn(OAc)22H2O
Ji, Xiang,Tong, Haibo,Yuan, Yu
, p. 372 - 379 (2011)
The Zn(OAc)22H2O-catalyed Michael addition reaction of indole to electron-deficient nitroolefins to afford the corresponding adducts in good to excellent yields with high selectivity is reported.
