75921-68-5Relevant academic research and scientific papers
Nickel-catalyzed intelligent reductive transformation of the aldehyde group using hydrogen
Tong, Xinli,Guo, Pengfei,Liao, Shengyun,Xue, Song,Zhang, Haigang
, p. 5828 - 5840 (2019/11/11)
The selective transformation of the aldehyde group (-CHO) in multifunctional oxygenates is a key challenge in the development of sustainable biomass feedstock. Herein, a smart Ni-MFC catalyst was developed from a 2D Ni-based metal-organic framework (MOF), which efficiently promoted the transformation of -CHO in the presence of H2 to a methyl group (-CH3) via the reductive etherification and hydrogenolysis of the C-O ether bond in methanol. Moreover, the catalytic process could be controlled to directionally produce methyl ether (-CH2OR) using the reductive etherification protocol. For the catalytic reduction of vanillin, the Ni-MFC-700 catalyst guaranteed the full conversion of vanillin and 96.5% yield of the desired 2-methoxy-4-methylphenol (MMP), while the Ni-MFC-500 catalyst afforded about 82.7% yield of 4-(methoxymethyl)-2-methoxyphenol in methanol solvent. This is a novel and promising approach for the valorization of multifunctional oxygenates and biomass-derived platform compounds.
Mild and selective deprotection of tert -butyl(dimethyl)silyl ethers with catalytic amounts of sodium tetrachloroaurate(III) dihydrate
Zhang, Qi,Kang, Xiuqin,Long, Lei,Zhu, Lijuan,Chai, Yonghai
, p. 55 - 64 (2015/02/02)
A simple and mild method for the removal of tert-butyl(dimethyl)silyl (TBS) protecting groups with catalytic amounts of sodium tetrachloroaurate(III) dihydrate is described. The procedure permits selective deprotection of aliphatic TBS ethers in good to excellent yields in the presence of aromatic TBS ethers, aliphatic triisopropylsilyl ethers, aliphatic tert-butyl(diphenyl)silyl ethers, or sterically hindered aliphatic TBS ethers. Additionally, TBS ethers can also be transformed into 4-methoxybenzyl ethers or methyl ethers in one pot by using larger quantities of the catalyst and a higher reaction temperature.
Highly chemoselective hydrogenation of active benzaldehydes to benzyl alcohols catalyzed by bimetallic nanoparticles
Liu, Chulong,Bao, Hailin,Wang, Dingsheng,Wang, Xinyan,Li, Yadong,Hu, Yuefei
, p. 6460 - 6462 (2015/11/16)
By using novel Pd/Ni bimetallic nanoparticles as a catalyst, the active benzaldehydes were hydrogenated to the corresponding benzyl alcohols as unique products in practical quantitative yields. The undesired catalytic hydrogenolysis of the benzyl alcohol was inhibited completely. By using this hydrogenation as a key step, the total synthesis of the natural product gastrodin was achieved with less total steps and a higher total yield.
A concise atroposelective formal synthesis of (-)-steganone
Yalcouye, Boubacar,Choppin, Sabine,Panossian, Armen,Leroux, Frédéric R.,Colobert, Fran?oise
, p. 6285 - 6294 (2015/03/30)
We describe herein the atroposelective formal synthesis of (-)-steganone, a parent member of Steganotaenia araliacea dibenzocyclooctadiene lignan lactones. Our synthesis features an atropodiastereoselective biaryl Suzuki-Miyaura cross-coupling reaction with de up to 99% using as a chiral auxiliary an enantiopure and efficiently converted β-hydroxy sulfoxide derivative. A highly atroposelective formal synthesis of (-)-steganone is described highlighting the use of an enantiopure sulfoxide as a chiral auxiliary in the Suzuki-Miyaura cross-coupling reaction.
HIV INTEGRASE INHIBITORY OXOISOINDOLINE SULFONAMIDES
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Page/Page column 63, (2013/03/26)
Novel oxoisoindoline sulfonamide integrase inhibitors are useful to inhibit HIV activity, and are therefore suitable for treatment or prophylaxis of HIV infection, for example in the treatment or prevention of AIDS. In particular embodiments, the inhibito
Transformations of several monoterpenoids in the presence of aldehydes in supercritical solvents
Anikeev,Sivcev,Il'Ina,Korchagina,Statsenko,Volcho,Salakhutdinov
, p. 382 - 387 (2013/07/26)
The reactivity of verbenol epoxide and isopulegol in supercritical solvents in the presence of aromatic aldehydes was studied using a flow type reactor and a heterogeneous catalyst (Al2O3) or no catalyst. The intramolecular transformations or interactions of reagents with the solvent prevailed in all cases; the yield of the products of intermolecular reactions of terpenoids with aldehydes was up to 1%. The aldehydes did not interact with verbenol epoxide but produced a considerable effect on the distribution of its isomerization products.
6,7-Dihydroxy-1-oxoisoindoline-4-sulfonamide-containing HIV-1 integrase inhibitors
Zhao, Xue Zhi,Maddali, Kasthuraiah,Smith, Steven J.,Métifiot, Mathieu,Johnson, Barry C.,Marchand, Christophe,Hughes, Stephen H.,Pommier, Yves,Burke Jr., Terrence R.
supporting information, p. 7309 - 7313 (2013/02/21)
Although an extensive body of scientific and patent literature exists describing the development of HIV-1 integrase (IN) inhibitors, Merck's raltegravir and Gilead's elvitegravir remain the only IN inhibitors FDA-approved for the treatment of AIDS. The em
Ion pairing effects on the regioselectivity of arylic versus benzylic C-O bond reductive cleavage: synthetic applications
Azzena, Ugo,Dettori, Giovanna,Mascia, Ilaria,Pisano, Luisa,Pittalis, Mario
, p. 11998 - 12006 (2008/03/14)
The regioselectivity of the reductive cleavage of 3,4,5-trimethoxybenzyl methyl ether strongly depends on the alkali metal employed as a reducing agent and solvent effects. Reactions run using Na as a reducing agent led to aromatic C(4)-O bond cleavage, whilst reductions run in the presence of Na/15-crown-5, or using Li as a reducing agent, led to highly regioselective benzylic C-O bond cleavage. This regioselectivity turnaround is discussed in terms of major solvent effects affecting the fragmentation paths of a common reaction intermediate. Synthetic applications of these findings led to the synthesis of biologically active compounds, like 2,5-dialkyl-substituted resorcinols, or 1-(3,4,5-trimethoxyphenyl)-2-arylethanes structurally related to combretastatin.
A solvent-controlled highly efficient Pd-C catalyzed hydrogenolysis of benzaldehydes to methylbenzenes via a novel 'acetal pathway'
Xing, Lixin,Wang, Xinyan,Cheng, Chuanjie,Zhu, Rui,Liu, Bo,Hu, Yuefei
, p. 9382 - 9386 (2008/02/10)
Pd-C catalyzed hydrogenolysis of benzaldehydes to methylbenzenes has been described to proceed via a 'benzenemethanol pathway'. In this article, a novel 'acetal pathway' was first revealed by a systematic study when lower alcohols were used as solvents and a solvent-controlled highly efficient procedure was established.
The Photochemistry of Methoxy-Substituted Benzyl Acetates and Benzyl Pivalates: Homolytic vs Heterolytic Cleavage
Pincock, J. A.,Wedge, P. J.
, p. 5587 - 5595 (2007/10/02)
The multiple methoxy-substituted benzyl acetates (3g-i) and benzyl pivalates (4g-i) have been photolyzed in methanol solution.The products of these reactions are derived from two critical intermediates; the benzyl radical/acyloxy radical pair and the benzyl cation/carboxylate anion pair.As predicted by the meta effect, the yield of ion-derived product, the methyl ether in this case, was enhanced by the presence of the m-methoxy groups.The yield of ether, for the acetate esters, varied from 2percent for the 4-methoxy-substituted ester to 66percent for the 3,4,5-trimethoxy-substituted ester.In contrast, the yield of ether, for the pivalate esters, varied from 1percent for the 4-methoxy-substituted ester to 20percent for the 3,4,5-trimethoxy-substituted one.The meta effect does not explain these differences; electron transfer converting the radical pair to the ion pair is still an important pathway in the mechanism for ion formation.A quantitative analysis of the yield of the ethers was done in order to obtain the electron-transfer rate constants.This analysis revealed that the yield of the ethers was higher than expected based on previous results for other substituted benzyl acetates.A possible explanation for this discrepancy is that internal return of the radical pair to starting material for the acetate esters is more efficient than for the pivalate esters.Also, the esters 3k and 3l, were prepared to study the effect of electron-withdrawing groups in the meta position.For these esters, the benzylic cleavage reactions were inefficient and an isomerization reaction, the benzvalene rearrangement, was competitive.
