31582-29-3Relevant academic research and scientific papers
Pyridine Nucleus Hydroxylation with Copper Oxygenase Models
Reglier, Marius,Amadei, Edith,Tadayoni, Rahim,Waegell, Bernard
, p. 447 - 450 (1989)
Reaction of iodosylbenzene with CuI complexes (2a,b) occurs with hydroxylation in the ortho position of one pyridine nucleus; CuIII=O species are postulated.
Exploring the acidic catalytic role of differently structured deep eutectic solvents in the aza-Michael addition of amines to 2-vinylpiridine
Ballarotto, Marco,Cappellini, Federico,Del Giacco, Tiziana,Di Profio, Pietro,Germani, Raimondo,Maestri, Riccardo,Tiecco, Matteo
, (2020/08/26)
Abstract: The search for innovative and green reaction media is a prominent topic in the recent research in chemistry. Deep Eutectic Solvents (DESs) are currently gaining relevance in this field thanks to their unique properties in terms of their “greenness” as well as in terms of their catalytic properties. In this work we developed an efficient protocol for the conjugate aza-Michael addition of amines to 2-vinylpyridine using 14 differently structured acid DESs as both reaction media and catalysts, so preventing the use of other acid additives. The results are influenced by the acidity of the components of the DESs, showing the best results with weak acids in the DESs components, with isolated yields up to 86%. The aza-Michael reaction is a widely used synthetic route for the C–N bond formation in organic synthesis. In particular, the addition of amines to 2-vinylpyridine is used for the realization of pharmaceutically relevant compounds with anticancer, antiarrhythmic, and analgesic properties. Comparing the results with the ones observed in literature for the same reaction, this procedure revealed to be a convenient and efficient method for this relevant transformation. Graphic abstract: [Figure not available: see fulltext.]
Benzylic ligand hydroxylation starting from a dicopper μ- I·2:I·2 peroxo intermediate: Dramatic acceleration of the reaction by hydrogen-atom donors
Rolff, Malte,Hamann, Jessica Nadine,Tuczek, Felix
supporting information; experimental part, p. 6924 - 6927 (2011/08/06)
Radicals in directed pathways: The μ-I·2: I·2 peroxo CuII2 intermediate 1 shows a much faster benzylic ligand hydroxylation than systems without phenol. This novel reactivity can be further accelerated by addition of external H-atom donors such as TEMPO-H. The results imply initial H-atom transfer leading to the formation of phenoxyl radicals. A highly reactive copper oxyl intermediate is then formed, which inserts oxygen into the benzylic C-H bond. Copyright
Towards co-operative reactivity in conjoint classical-organometallic heterometallic complexes: The co-ordination chemistry of novel ligands with triphenylphosphine and bis(pyridylethyl)amine or triazacyclononane domains
Watkins, Scott E.,Craig, Donald C.,Colbran, Stephen B.
, p. 2423 - 2436 (2007/10/03)
With a view towards later studies of co-operativity in heteronuclear complexes with hard classical (oxygen-activating) and soft organometallic (organic-substrate binding) metal centres, four novel ditopic N3P-donor ligands (L1-L4), each comprising triphenylphosphine tethered to an N,N′-bis(2-pyridyl-2-ethyl)amine (bpea) or a 1,4-diisopropyl-1,4,7-triazacyclononane (tacn*) N3-donor group, have been designed and prepared by reductive aminations of ortho- and meta-(diphenylphosphino)benzaldehydes with bpea (for L1 and L3) and tacn* (for L2 and L4). A range of κNn, κP-chelate mononuclear complexes have been isolated from the reactions of the ortho-substituted ligands, L1 and L2, with Cu(I), Zn(II) and Pt(II) sources, and the X-ray crystal structures of [Cu(L1)][PF6], [Cu(L2)][PF6] (communicated in: S. E. Watkins, D. C. Craig and S. B. Colbran, J. Chem. Soc., Dalton Trans., 1999, 1539) and [PtCl(L1)][PF6] have been determined. Six complexes with the phosphine of L1-L4 co-ordinated to a softer [Pt(II), Ir(I) or W(O)] metal centre and with dangling, metal-free N3-donor domains have been prepared: for the ortho-substituted ligands L1 and L2, it was necessary to protect the hard, more basic N3-donor domains by protonation (pH control) to prevent formation of κNn, κP-chelate mononuclear complexes; for the meta-substituted ligands L3 and L4, pH control was unnecessary as the phosphine group selectively binds to the softer metal ions. The complex trans-[IrCl(CO)(L3)2] reversibly forms a dioxygen adduct. An Ir(III)Cu(II)2 and four Pt(II)Cu(II)2 heterometallic complexes were prepared by adding hard Cu(II) ions to the Ir(I) and Pt(II) complexes with metal-free N3-donor domains, and the full characterisation of these is described. The tungsten(O) carbonyl complex [W(CO)5(L3)], with a metal-free N3-bpea domain, was prepared for a study of metal ion recognition. No perturbation of the carbonyl region of the IR spectrum was observed when metal ions were added. The effect of submolar quantities of heterometallic complexes, obtained by adding a first d-series metal(II) ion (2 equivalents) to [IrCl(CO)(L3)2], on the oxidation of styrene by oxygen in methylethyl ketone has been assayed: inhibition of the oxidation is observed with the %conversion and the product selectivity dependant on the metal(II) ion.
