4105-92-4Relevant articles and documents
REACTION OF NUCLEOBASES WITH α-ACETYLENIC ESTERS, POTENTIALLY USEFULL FOR CHEMICAL MODIFICATION OF NUCLEIC ACIDS
Olomucki, M.,Gall, J. Y., Le,Colinart, S.,Durant, F.,Norberg, B.,Evrard, G.
, p. 3471 - 3474 (1984)
The NH2 group and the adjacent ring nitrogen of adenosine and cytidine react with α-acetylenic esters by addition across the triple bond and formation of a lactam with the ester group.
Trisannelation of acrylates to 1,3,5-benzenetricarboxylates by a Pd(OAc)2/HPMoV/CeCl3/O2 system
Tamaso, Ken-Ichi,Hatamoto, Yuji,Sakaguchi, Satoshi,Obora, Yasushi,Ishii, Yasutaka
, p. 3603 - 3605 (2007)
(Chemical Equation Presented) A new type of trisannelation reaction of acrylates through acetal formation was developed by Pd(OAc)2 combined with molybdovanadophosphoric acid (HPMo8V4) and Lewis acid under atmospheric diox
Understanding the Incorporation and Release of Salicylic Acid in Metal-Organic Frameworks for Topical Administration
Rojas, Sara,Horcajada, Patricia
, p. 1325 - 1331 (2021)
Although metal-organic frameworks (MOFs) have been widely demonstrated to be great candidates for drug delivery applications, they have been mainly proposed for the intravenous route. Here, eight highly porous benchmarked MOFs, with different topologies a
Iron-catalyzed trimerization of terminal alkynes enabled by pyrimidinediimine ligands: A regioselective method for the synthesis of 1,3,5-substituted arenes
Doll, Julianna S.,Eichelmann, Robert,Hertwig, Leif E.,Bender, Thilo,Kohler, Vincenz J.,Bill, Eckhard,Wadepohl, Hubert,Ro?ca, Drago?-Adrian
, p. 5593 - 5600 (2021/05/31)
The development of pyrimidine-based analogues of the well-known pyridinediimine (PDI) iron complexes enables access to a functional-group-tolerant methodology for the catalytic trimerization of terminal aliphatic alkynes. Remarkably, in contrast to established alkyne trimerization protocols, the 1,3,5-substituted arenes are the main reaction products. Preliminary mechanistic investigations suggest that the enhanced π-acidity of the pyrimidine ring, combined with the hemilability of the imine groups coordinated to the iron center, facilitates this transformation. The entry point in the catalytic cycle is an isolable iron dinitrogen complex. The catalytic reaction proceeds via a 1,3-substituted metallacycle, which explains the observed 1,3,5-regioselectivity. Such a metallacycle could be isolated and represents a rare 1,3-substituted ferracycle obtained through alkyne cycloaddition.
Cyclotrimerization of alkynes catalyzed by a self-supported cyclic tri-nuclear nickel(0) complex with α-diimine ligands
Shen, Lingyi,Zhao, Yanxia,Luo, Qiong,Li, Qian-Shu,Liu, Bin,Redshaw, Carl,Wu, Biao,Yang, Xiao-Juan
supporting information, p. 4643 - 4649 (2019/04/05)
A cyclic tri-nuclear α-diimine nickel(0) complex [{Ni(μ-LMe-2,4)}3] (2) was synthesized from a “pre-organized”, trimerized trigonal LNiBr2-type precursor [Ni3(μ2-Br)3(μ3-Br)2(LMe-2,4)3]·Br (1; LMe-2,4 = [(2,4-Me2C6H3)NC(Me)]2). In complex 2, the α-diimine ligands not only exhibit the normal N,N′-chelating mode, but they also act as bridges between the Ni atoms through an unusual π-coordination of a C═N bond to Ni. Complex 2 is able to catalyze the cyclotrimerization of alkynes to form substituted benzenes in good yield and regio-selectivity for the 1,3,5-isomers, which is found to vary with the nature of the alkyne employed. This complex represents a convenient self-supported nickel(0) catalyst with no need for additional ligands and reducing agent.
Enhanced Catalytic Activity of Nickel Complexes of an Adaptive Diphosphine-Benzophenone Ligand in Alkyne Cyclotrimerization
Orsino, Alessio F.,Gutiérrez Del Campo, Manuel,Lutz, Martin,Moret, Marc-Etienne
, p. 2458 - 2481 (2019/03/08)
Adaptive ligands, which can adapt their coordination mode to the electronic structure of various catalytic intermediates, offer the potential to develop improved homogeneous catalysts in terms of activity and selectivity. 2,2′-Diphosphinobenzophenones have previously been shown to act as adaptive ligands, the central ketone moiety preferentially coordinating reduced metal centers. Herein, the utility of this scaffold in nickel-catalyzed alkyne cyclotrimerization is investigated. The complex [(p-tolL1)Ni(BPI)] (p-tolL1 = 2,2′-bis(di(para-tolyl)phosphino)-benzophenone; BPI = benzophenone imine) is an active catalyst in the [2 + 2 + 2] cyclotrimerization of terminal alkynes, selectively affording 1,2,4-substituted benzenes from terminal alkynes. In particular, this catalyst outperforms closely related bi- and tridentate phosphine-based Ni catalysts. This suggests a reaction pathway involving a hemilabile interaction of the C-O unit with the nickel center. This is further borne out by a comparative study of the observed resting states and DFT calculations.
Cyclotrimerization of phenylacetylene catalyzed by a cobalt half-sandwich complex embedded in an engineered variant of transmembrane protein FhuA
Thiel,Sauer,Mertens,Polen,Chen,Schwaneberg,Okuda
supporting information, p. 5452 - 5456 (2018/08/12)
An (η5-cyclopentadienyl)cobalt(i) complex was covalently incorporated into an engineered variant of the transmembrane protein ferric hydroxamate uptake protein component: A, FhuA ΔCVFtev, using a thiol-ene reaction. A CD spectrum shows the structural integrity of the biohybrid catalyst. MALDI-TOF of the segment containing the anchoring site for the cobalt complex Cys545 confirmed successful conjugation. This biohybrid catalyst catalyzed the cyclotrimerization of phenylacetylene to give a mixture of regioisomeric 1,2,4- and 1,3,5-triphenylbenzene in aqueous medium.
Reactions of dicobalt octacarbonyl with dinucleating and mononucleating bis(imino)pyridine ligands
Hollingsworth, Ryan L.,Beattie, Jeffrey W.,Grass, Amanda,Martin, Philip D.,Groysman, Stanislav,Lord, Richard L.
, p. 15353 - 15363 (2018/11/20)
This work focuses on the application of dicobalt octacarbonyl (Co2(CO)8) as a metal precursor in the chemistry of formally low-valent cobalt with redox-active bis(imino)pyridine [NNN] ligands. The reactions of both mononucleating mes
Silica Gel as a Promoter of Sequential Aza-Michael/Michael Reactions of Amines and Propiolic Esters: Solvent- and Metal-Free Synthesis of Polyfunctionalized Conjugated Dienes
Aleksi?, Jovana,Stojanovi?, Milovan,Baranac-Stojanovi?, Marija
, p. 1811 - 1835 (2018/07/29)
We present an efficient, simple, metal- and solvent-free silica-gel-promoted synthesis of functionalized conjugated dienes by sequential aza-Michael/Michael reactions by starting from commercially available primary amines and propiolic esters. The scope a
Divergent reactivity of a new dinuclear xanthene-bridged bis(iminopyridine) di-nickel complex with alkynes
Hollingsworth, Ryan L.,Bheemaraju, Amarnath,Lenca, Nicole,Lord, Richard L.,Groysman, Stanislav
, p. 5605 - 5616 (2017/07/10)
The reaction of a dinucleating bis(iminopyridine) ligand L bearing a xanthene linker (L = N,N′-(2,7-di-tert-butyl-9,9-dimethyl-9H-xanthene-4,5-diyl)bis(1-(pyridin-2-yl)methanimine)) with Ni2(COD)2(DPA) (COD = cyclooctadiene, DPA = diphenylacetylene) leads to the formation of a new dinuclear complex Ni2(L)(DPA). Ni2(L)(DPA) can also be obtained in a one-pot reaction involving Ni(COD)2, DPA and L. The X-ray structure of Ni2(L)(DPA) reveals two square-planar Ni centers bridged by a DPA ligand. DFT calculations suggest that this species features NiI centers antiferromagnetically coupled to each other and their iminopyridine ligand radicals. Treatment of Ni2(L)(DPA) with one equivalent of ethyl propiolate (HCCCO2Et) forms the Ni2(L)(HCCCO2Et) complex. Addition of the second equivalent of ethyl propiolate leads to the observation of cyclotrimerised products by 1H NMR spectroscopy. Carrying out the reaction under catalytic conditions (1 mol% of Ni2(L)(DPA), 24 h, room temperature) transforms 89% of the substrate, forming primarily benzene products (triethyl benzene-1,2,4-tricarboxylate and triethyl benzene-1,3,5-tricarboxylate) in 68% yield, in a ca. 5:1 relative ratio. Increasing catalyst loading to 5 mol% leads to the full conversion of ethyl propiolate to benzene products; no cyclotetramerisation products were observed. In contrast, the reaction is significantly more sluggish with methyl propargyl ether. Using 1 mol% of the catalyst, only 25% conversion of methyl propargyl ether was observed within 24 h at room temperature. Furthermore, methyl propargyl ether demonstrates the formation of cyclooctatetraenes in significant amounts at a low catalyst concentration, whereas a higher catalyst concentration (5 mol%) leads to benzene products exclusively. Density functional theory was used to provide insight into the reaction mechanism, including structures of putative dinuclear metallocyclopentadiene and metallocycloheptatriene intermediates.
