6921-34-2Relevant articles and documents
Highly variable Zr-CH2-Ph bond angles in tetrabenzylzirconium: Analysis of benzyl ligand coordination modes
Rong, Yi,Al-Harbi, Ahmed,Parkin, Gerard
, p. 8208 - 8217 (2012)
Analysis of a monoclinic modification of Zr(CH2Ph)4 by single-crystal X-ray diffraction reveals that the bond angles Zr-CH 2-Ph in this compound span a range of 25.1° , which is much larger than previously observed for the orthorhombic form (12.1°). In accord with this large range, density functional theory calculations demonstrate that little energy is required to perturb the Zr-CH2-Ph bond angles in this compound. Furthermore, density functional theory calculations on Me 3ZrCH2Ph indicate that bending of the Zr-CH2-Ph moiety in the monobenzyl compound is also facile, thereby demonstrating that a benzyl ligand attached to zirconium is intrinsically flexible, such that its bending does not require a buffering effect involving another benzyl ligand.
Polymer supporeted 'Magnesium(anthracene)': Effective in Forming Benzylic Grignard Reagents (via Electron Transfer Reactions)
Harvey, Stephen,Raston, Colin L.
, p. 652 - 653 (1988)
A polymer supported 'magnesium(anthracene)' (4) has been prepared from the reaction in tetrahydrofuran (thf) of (1) with polystyrene bearing -9-CH2SiMe2(C14H9) groups (3); the green paramagnetic solid, containing dianion radical anion anthracene sites, yields Grignard reagents (>90percent) with benzylic halides in thf via electron transfer reactions, as does the model compound for the dianion sites, viz. (thf)2> (6).
Scalable Continuous Synthesis of Grignard Reagents from in Situ-Activated Magnesium Metal
Deitmann, Eva,G?ssl, Lars,Hofmann, Christian,L?b, Patrick,Menges-Flanagan, Gabriele
, p. 315 - 321 (2020/03/10)
The continuous synthesis of Grignard reagents has been investigated under continuous processing conditions using Mg turnings at variable liquid throughputs and concentrations. A novel process window easily accessible through continuous processing was employed, namely, using a large molar access of Mg turnings within the reactor and achieving Mg activation by mechanical means. A laboratory and a 10-fold-increased pilot-scale reactor setup were built and evaluated, including integrated inline analytics via ATR-IR measurements. The main goal of this work was to explore the full potential of classic Grignard reagent formation through the use of scalable flow chemistry and to allow for fast and safe process optimization. It was found that on both the laboratory and pilot scales, full conversion of the employed halides could be achieved with a single passage through the reactor. Furthermore, Grignard reagent yields of 89-100% were reached on the laboratory scale.
Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides
Adamo, Andrea,Berton, Mateo,McQuade, D. Tyler,Sheehan, Kevin
supporting information, p. 1343 - 1356 (2020/07/10)
Magnesium organometallic reagents occupy a central position in organic synthesis. The freshness of these compounds is the key for achieving a high conversion and reproducible results. Common methods for the synthesis of Grignard reagents from metallic magnesium present safety issues and exhibit a batch-to-batch variability. Tubular reactors of solid reagents combined with solution-phase reagents enable the continuous-flow preparation of organomagnesium reagents. The use of stratified packed-bed columns of magnesium metal and lithium chloride for the synthesis of highly concentrated turbo Grignards is reported. A low-cost pod-style synthesizer prototype, which incorporates single-use prepacked perfluorinated cartridges and bags of reagents for the automated on-demand lab-scale synthesis of carbon, nitrogen, and oxygen turbo magnesium bases is presented. This concept will provide access to fresh organomagnesium reagents on a discovery scale and will do so independent from the operator’s experience in flow and/or organometallic chemistry.
Redox-Active Ligand-Assisted Two-Electron Oxidative Addition to Gallium(II)
Fedushkin, Igor L.,Dodonov, Vladimir A.,Skatova, Alexandra A.,Sokolov, Vladimir G.,Piskunov, Alexander V.,Fukin, Georgii K.
, p. 1877 - 1889 (2018/01/27)
The reaction of digallane (dpp-bian)Ga?Ga(dpp-bian) (2) (dpp-bian=1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) with allyl chloride (AllCl) proceeded by a two-electron oxidative addition to afford paramagnetic complexes (dpp-bian)Ga(η1-All)Cl (3) and (dpp-bian)(Cl)Ga?Ga(Cl)(dpp-bian) (4). Treatment of complex 4 with pyridine induced an intramolecular redox process, which resulted in the diamagnetic complex (dpp-bian)Ga(Py)Cl (5). In reaction with allyl bromide, complex 2 gave metal- and ligand-centered addition products (dpp-bian)Ga(η1-All)Br (6) and (dpp-bian-All)(Br)Ga?Ga(Br)(dpp-bian-All) (7). The reaction of digallane 2 with Ph3SnNCO afforded (dpp-bian)Ga(SnPh3)2 (8) and (dpp-bian)(NCO)Ga?Ga(NCO)(dpp-bian) (9). Treatment of GaCl3 with (dpp-bian)Na in diethyl ether resulted in the formation of (dpp-bian)GaCl2 (10). Diorganylgallium derivatives (dpp-bian)GaR2 (R=Ph, 11; tBu, 14; Me, 15; Bn, 16) and (dpp-bian)Ga(η1-All)R (R=nBu, 12; Cp, 13) were synthesized from complexes 3, 10, Bn2GaCl, or tBu2GaCl by salt metathesis. The salt elimination reaction between (dpp-bian)GaI2 (17) and tBuLi was accompanied by reduction of both the metal and the dpp-bian ligand, which resulted in digallane 2 as the final product. Similarly, the reaction of complex 10 with MentMgCl (Ment=menthyl) proceeded with reduction of the dpp-bian ligand to give the diamagnetic complex [(dpp-bian)GaCl2][Mg2Cl3(THF)6] (18). Compounds 11, 12, 13, 15, and 16 were thermally robust, whereas compound 14 decomposed when heated at reflux in toluene to give complex (dpp-bian-tBu)GatBu2 (19). Both complexes 7 and 19 contain R-substituted dpp-bian ligand: in the former compound the allyl group was attached to the imino-carbon atom, whereas in complex 19, the tBu group was situated on the naphthalene ring. Crystal structures of complexes 3, 8, 9, 10, 13, 14, 18, and 19 were determined by single-crystal X-ray analysis. The presence of dpp-bian radical anions in 3, 6, 8, and 10–16 was determined by ESR spectroscopy.
Regioselective 1,4-conjugate addition of grignard reagents to nitrodienes in the presence of catalytic amounts of Zn(II) salts
Dhakal, Ramesh C.,Dieter, R. Karl
supporting information, p. 1362 - 1365 (2014/04/03)
Grignard reagents undergo facile regioselective 1,4-conjugate addition to nitrodienes in the presence of catalytic amounts of Zn(II) salts with excellent yields. A wide range of ligands such as alkyl, aryl, heteroaryl, allyl, vinyl, 1-alkynyl, and alkoxy ligands were transferred, while a thiolate ligand afforded 1,6-regioselectivity. The reactions were successfully carried out on δ-alkyl- or aryl-substituted α,β,γ,δ-diunsaturated nitrodiene substrates. Regioselectivity is minimally influenced by temperature or choice of solvent.
PROCESS FOR THE PREPARATION OF GRIGNARD COMPOUNDS
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Page/Page column 8, (2010/11/03)
The invention relates to a process for the preparation of Grignard compounds using a continuous method which involves the reaction of an organic halide dissolved in an organic solvent with metallic magnesium which, together with the activator solution in an organic solvent, fills the flow reactor or optionally a system of flow reactors, and subsequently, the resulting reaction mixture is fed into the terminal flow reactor containing metallic magnesium in order to achieve complete conversion of the organic halide, whereby preferably the organic solvent is re-circulated to flow reactors in a form of vapour.
N-acyl sulfamic acid esters (or thioesters), N-acyl sulfonamides, and N-sulfonyl carbamic acid esters (or thioesters) as hypercholesterolemic agents
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, (2008/06/13)
The present invention is directed to compounds useful for the regulation of cholesterol of Formula I, methods for using them and pharmaceutical compositions thereof, STR1 wherein X and Y are oxygen, sulfur, or (CR'R")n wherein n is 1 to 4; R is hydrogen, alkyl, or benzyl; R1 and R2 are phenyl, substituted phenyl, naphthyl, substituted naphthyl, an aralkyl group, an alkyl chain, adamantyl, or a cycloalkyl group.
C-GLYCOSIDE ANALOGUES OF N-(4-HYDROXYPHENYL)RETINAMIDE-O-GLUCURONIDE
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, (2008/06/13)
The present invention provides breast cancer chemopreventive arylamide analogues of retinoic acid, more particularly C-glycoside analogues of N-(4-hydroxyphenyl)retinamide-O-glucuronide and N-glycoside analogue of retinoyl beta-glucuronide that resist both beta-glucuronidase mediated enzymatic hydrolysis as well as acid catalyzed hydrolysis. Specifically, the drugs include 4-(retinamido)phenyl-C-glucuronide; 4-(retinamido)phenyl-C-glucoside; 4-(retinamido)benzyl-C-xyloside; 4-(retinamido)benzyl-C-glucoside; 4-(retinamido)benzyl-C-glucuronide; 4-(retinamido)phenyl-C-xyloside, 1-(B-D-lucopyranosyl) retinamide and 1-(D-glucopyranosyluronosly) retinamide. The invention also relates to a method for making such drugs.
Mechanical Activation of Magnesium Turnings for the Preparation of Reactive Grignard Reagents
Baker, Karen V.,Brown, John M.,Hughes, Nigel,Skarnulis, A. Jerome,Sexton, Ann
, p. 698 - 703 (2007/10/02)
Preactivation of magnesium by dry stirring in an inert atmosphere is highly beneficial for the clean synthesis of reactive allylic or benzylic organomagnesium chlorides.This procedure routinely produces 0.4 M solutions of the Grignard reagent in diethyl ether free from coupling products.The purity may be directly assayed by 13C spectroscopy.Using spin saturation transfer techniques, the rate constant for interconversion of the enantiomers of (1-phenyl-2-methylpropyl)magnesium chloride in Et2O at 25 deg C was shown to be -1.Electron microscopy has been used to define the surface changes occurring during the dry stirring of magnesium turnings.
