- Nickel-Catalyzed Markovnikov Transfer Hydrocyanation in the Absence of Lewis Acid
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Hydrocyanation in the absence of toxic HCN gas is highly desirable. Addressing that challenge, transition-metal-catalyzed transfer hydrocyanation using safe HCN precursors has been developed, but these reagents generally require a Lewis acid for activation, and the control of regioselectivity often remains problematic. In this Letter, a Ni-catalyzed highly Markovnikov-selective transfer hydrocyanation that operates in the absence of any Lewis acid is reported. The readily prepared pro-aromatic 1-isopropylcyclohexa-2,5-diene-1-carbonitrile is used as the HCN source, and the reaction shows a broad substrate scope and high functional group tolerance. Terminal styrene derivatives, dienes, and internal alkynes are converted with good to excellent selectivities. Mechanistic studies provide insights into the origin of the regioselectivity.
- Frye, Nils L.,Bhunia, Anup,Studer, Armido
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supporting information
p. 4456 - 4460
(2020/06/03)
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- Preparation method of alkyl nitrile compound
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The invention discloses a preparation method of an alkyl nitrile compound. Specifically, the preparation method comprises the following step: in an organic solvent, in the presence of a protective gasand under the action of a catalyst, carrying out a reduction reaction as shown in the specification on olefin as shown in a formula I, a cyanation reagent and water, wherein the alkyl nitrile compound 1 is a compound II and/or a compound III. The preparation method provided by the invention is mild in condition, can realize hydrocyanation of olefin more safely and efficiently, and has good substrate universality and functional group compatibility.
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Paragraph 0130-0132; 0150-0152
(2020/08/18)
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- Enantioselective Nickel-Catalyzed Hydrocyanation using Chiral Phosphine-Phosphite Ligands: Recent Improvements and Insights
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The asymmetric hydrocyanation of vinylarenes was investigated using hydrogen cyanide (HCN) in the presence of 5 mol% of a catalyst prepared from a phenol-derived chiral phosphine-phosphite ligand and bis(cyclooctadiene)nickel [Ni(cod)2]. The reactions were performed in tetrahydrofuran (THF) at room temperature to give exclusively the branched nitriles with superior enantioselectivities of 88-99% ee for vinylarenes and 74-94% ee for vinylheteroarenes, respectively. Using styrene as a model substrate it was shown that the catalyst loading could be decreased to 0.42 mol% without any loss of selectivity (88% ee). The structure of the pre-catalyst, i.e., a tetrahedral Ni(0)(P,P-chelate)(cod) complex, was proven by X-ray and NMR analysis. Additional insight into the reaction course was gained by monitoring the hydrocyanation of styrene-d8 by means of 2D NMR spectroscopy.
- Falk, Anna,Cavalieri, Alberto,Nichol, Gary S.,Vogt, Dieter,Schmalz, Hans-Günther
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p. 3317 - 3320
(2015/11/03)
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- Synthesis and immunosuppressive activity of new artemisinin derivatives. 1. [12(β or α)-dihydroartemisininoxy]phen(ox)yl aliphatic acids and esters
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A series of novel dihydroartemisinin derivatives were synthesized and evaluated on their immunosuppressive activity in the search for potential immunosuppressive agents with high efficacy and low toxicity. These compounds were assayed in their cytotoxicity of lymphocyte, inhibition activity on concanavalin A (ConA) induced T cell proliferation and lipopolysaccharide (LPS) induced B cell proliferation. Among them, 11b, 13b, 14d, 15b, 16, and 17 remarkably exhibited lower cytotoxicity and higher inhibition activity on the mitogen-induced T cell and B cell proliferation in comparison with artemisinin, artesunate, and artemether in vitro. More significantly, compound 11b displayed reduced cytotoxicity by over 100-fold compared with cyclosporin A (CsA) and comparable inhibition activity (SI = 848) on ConA-induced T cell proliferation to CsA (SI = 963) and more than 4000 times the inhibitory effect (SI = 28473) on LPS-induced B cell proliferation compared with CsA (SI = 7) in vitro. The in vivo experimental results showed that compound 16 could inhibit 2,4-dinitrofluorobenzene (DNFB)-induced delayed-type hypersensitivity (DTH) reaction and sheep red blood cell (SRBC) induced antibody production, respectively. The structure and activity relationships (SAR) of these compounds were also discussed.
- Yang, Zhong-Shun,Zhou, Wen-Liang,Sui, Yi,Wang, Jun-Xia,Wu, Jin-Ming,Zhou, Yu,Zhang, Yu,He, Pei-Lan,Han, Ji-Ye,Tang, Wei,Li, Ying,Zuo, Jian-Ping
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p. 4608 - 4617
(2007/10/03)
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- Esters and amides of substituted fused ring phenyl acetic acids
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Esters and amides of substituted fused ring phenyl acetic acids having the formula wherein Y, together with the ring to which it is fused forms a multi-ring system selected from napthyl, [1]benzopyranol [2, 3-b], pyridine, phenothiazine, carbazole, and benzoxazole;, R1 is lower alkyl or hydrogen;, R2 is one or more independently selected from cyano, nitro, amino, alkylamino, hydrogen, halogen, lower alkyl, lower alkoxy, hydroxy, phenyl or phenyl substituted with halogen, alkyl or alkoxy;, wherein Q is the deprotonated residue of a polymer or macromolecular structure having a molecular weight of at least 1000 containing at least two primary and/or secondary amino groups and/or hydroxy groups; and, n is an integer of at least 2 are useful in treating colonic polyps.
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- Benzoxazole derivatives in treating inflammation, pain and fever
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The invention provides novel 5- and 6-benzoxazolyl alkanoic acids, optionally substituted in the 2-position, and derivatives thereof which possess anti-inflammatory, anti-pyretic and analgesic activity. Also provided is a process for preparing such compounds by cyclising an appropriately substituted o-aminophenol and, if necessary, converting the resultant benzoxazole to the desired compound.
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