42900-89-0Relevant academic research and scientific papers
Lewis acid promoted ruthenium(II)-catalyzed etherifications by selective hydrogenation of carboxylic acids/esters
Li, Yuehui,Topf, Christoph,Cui, Xinjiang,Junge, Kathrin,Beller, Matthias
supporting information, p. 5196 - 5200 (2015/04/27)
Ethers are of fundamental importance in organic chemistry and they are an integral part of valuable flavors, fragrances, and numerous bioactive compounds. In general, the reduction of esters constitutes the most straightforward preparation of ethers. Unfortunately, this transformation requires large amounts of metal hydrides. Presented herein is a bifunctional catalyst system, consisting of Ru/phosphine complex and aluminum triflate, which allows selective synthesis of ethers by hydrogenation of esters or carboxylic acids. Different lactones were reduced in good yields to the desired products. Even challenging aromatic and aliphatic esters were reduced to the desired products. Notably, the in situ formed catalyst can be reused several times without any significant loss of activity. An assist from Al: A bifunctional catalyst system consisting of a Ru/phosphine complex and aluminum triflate allows selective hydrogenation of esters to ethers. A variety of lactones were reduced to the desired products in good yields. The catalyst further provides a general method for the reduction of linear esters and reductive etherification of carboxylic acids with alcohols.
Acceleration effect of an allylic hydroxy group on ring-closing enyne metathesis of terminal alkynes: Scope, application, and mechanistic insights
Imahori, Tatsushi,Ojima, Hidetomo,Yoshimura, Yuichi,Takahata, Hiroki
supporting information; experimental part, p. 10762 - 10771 (2009/12/01)
An interesting acceleration effect of an allylic hydroxy group on ring-closing enyne metathesis has been found. Ring-closing enyne metathesis of terminal alkynes possessing an allylic hydroxy group proceeded smoothly without the ethylene atmosphere generally necessary to promote the reaction. The synthesis of (+)-isofagomine with the aid of this efficient reaction has been demonstrated. Mechanistic studies of the acceleration effect were also carried out. Results of NMR studies suggested that the reaction proceeded via an "ene-then-yne" pathway. Kinetic studies indicated switching of the rate-determining step as a consequence of the presence of an allylic hydroxy group. These results suggest acceleration of the reentry step of Ru-carbene species by the allylic hydroxy group.
Catalytic one-pot synthesis of cyclic amidines by virtue of tandem reactions involving intramolecular hydroamination under mild conditions
Chang, Sukbok,Lee, Minjae,Jung, Doo Young,Yoo, Eun Jeong,Cho, Seung Hwan,Han, Sun Kyu
, p. 12366 - 12367 (2007/10/03)
A new synthetic methodology for the generation of cyclic amidines has been developed by the reaction of 1,n-aminoalkynes with electron-deficient azides using a ruthenium catalyst at ambient temperature. The reaction proceeds most likely via a tandem sequence of intramolecular hydroamination of aminoalkynes, cycloaddition of azides with the resulting enamines, and rearrangement of triazoline intermediates. It demonstrates, as the proof-of-principle, that an equilibria cascade sequence can be favorably driven by an irreversible step, thus enabling a facile one-pot synthetic route to deliver molecular complexity under unprecedented mild conditions without relying on the traditional linear approaches. Copyright
Syntheses and biological evaluation of vinblastine congeners.
Kuehne, Martin E,Bornmann, William G,Marko, Istvan,Qin, Yong,LeBoulluec, Karen L,Frasier, Deborah A,Xu, Feng,Mulamba, Tshilundu,Ensinger, Carol L,Borman, Linda S,Huot, Anne E,Exon, Christopher,Bizzarro, Fred T,Cheung, Julia B,Bane, Susan L
, p. 2120 - 2136 (2007/10/03)
Sixty-two congeners of vinblastine (VLB), primarily with modifications of the piperidine ring in the carbomethoxycleavamine moiety of the binary alkaloid, were synthesized and evaluated for cytotoxicity against murine L1210 leukemia and RCC-2 rat colon cancer cells, and for their ability to inhibit polymerization of microtubular protein at 10(7) M concentrations was found for L1210 inhibition by these compounds, with the most active 1000x as potent as vinblastine.
Almond oxynitrilase-catalyzed transformation of aldehydes is strongly influenced by naphthyl and alkoxy substituents
Roda, Gabriella,Riva, Sergio,Danieli, Bruno
, p. 3939 - 3949 (2007/10/03)
Different α- and β-substituted aldehydes have been submitted to the catalytic action of almond oxynitrilase (PaHNL), in order to explore the influence of a stereocenter already present in the substrate on the selectivity of this enzyme. The results indicate that naphthyl and alkoxy substituents in the α- and also in the β-position to the aldehyde group significantly influence the stereochemical outcome of the PaHNL-catalyzed transformation.
Novel alkaloids
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, (2008/06/13)
Cycloalkyl and aromatic vinblastine and vincristine derivatives useful as anti-tumor agents.
New Syntheses of Isochromene
Cottet, F.,Cottier, L.,Descotes, G.
, p. 497 - 498 (2007/10/02)
Isochromene is easily prepared in three steps either from the homophthalic acid (Route A) or from the 2-indanone (Route B).The synthetic Route B gives a better yield.
