- Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides
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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.
- Adamo, Andrea,Berton, Mateo,McQuade, D. Tyler,Sheehan, Kevin
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supporting information
p. 1343 - 1356
(2020/07/10)
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- Iron-Catalyzed Cross-Coupling of Alkynyl and Styrenyl Chlorides with Alkyl Grignard Reagents in Batch and Flow
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Transition-metal-catalyzed cross-coupling chemistry can be regarded as one of the most powerful protocols to construct carbon–carbon bonds. While the field is still dominated by palladium catalysis, there is an increasing interest to develop protocols that utilize cheaper and more sustainable metal sources. Herein, we report a selective, practical, and fast iron-based cross-coupling reaction that enables the formation of Csp?Csp3 and Csp2?Csp3 bonds. In a telescoped flow process, the reaction can be combined with the Grignard reagent synthesis. Moreover, flow allows the use of a supporting ligand to be avoided without eroding the reaction selectivity.
- Deng, Yuchao,Wei, Xiao-Jing,Wang, Xiao,Sun, Yuhan,No?l, Timothy
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supporting information
p. 14532 - 14535
(2019/11/21)
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- Synthesis, Properties, and Catalytic Application of a Triptycene-Type Borate-Phosphine Ligand
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A borate-containing caged triarylphosphine L-X (X = Na or NBu4), featuring a 9-phospha-10-boratriptycene framework, was synthesized and characterized by NMR spectroscopy and X-ray diffraction analysis. The NMR coupling constant of the corresponding phosphine selenide indicated a higher electron-donating property of the borate-phosphine L compared to that of the 9-phospha-10-silatriptycene derivative (Ph-TRIP). The coordination property of L-X to [PdCl(η3-allyl)]2 was dependent on the countercation, giving a neutral Pd complex [PdCl(η3-allyl)(L-NBu4)] from L-NBu4 in CH2Cl2 or a zwitterionic Pd complex [Pd(η3-allyl)(MeCN)(L)] from L-Na in MeCN/CH2Cl2. Utility of L-X as a ligand for metal catalysis was demonstrated in the Pd-catalyzed Suzuki-Miyaura cross-coupling of aryl chlorides.
- Konishi, Shota,Iwai, Tomohiro,Sawamura, Masaya
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p. 1876 - 1883
(2018/07/05)
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- Directional properties of fluorenylidene moieties in unsymmetrically substituted N-heterocyclic carbenes. Unexpected CH activation of a methylfluorenyl group with palladium. Use in palladium catalysed Suzuki-Miyaura cross coupling of aryl chlorides
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Benzimidazolium salts having their two nitrogen atoms substituted by different 9-alkylfluorenyl groups (4a-e and 4g, alkyl1/alkyl 2 = Me/Et, Me/Pr, Me/n-Bu, Me/i-Pr, Me/Bn, Me/CH2SMe have been synthesised in high yields in two or three steps from N,N′-bis(9H- fluoren-9-ylidene)benzene-1,2-diamine (1). The imidazolium salts 4a-e were converted readily into the corresponding PEPPSI-type palladium complexes (PEPPSI = pyridine-enhanced precatalyst preparation stabilisation and initiation), while reaction of the methylthioether-substituted salt 4g with PdCl 2/K2CO3/pyridine afforded the palladacycle 5g resulting from metallation of the methyl group attached to the fluorenylidene moiety. NMR and X-ray diffraction studies revealed that the carbene ligands in 5a-5e behave as clamp-like ligands, the resulting metal confinement arising from a combination of the orientational properties of the fluorenylidene moieties that push the alkyl groups towards the metal centre and attractive anagostic interactions involving CH2(fluorenyl) groups. Complexes 5a-e were assessed in Suzuki-Miyaura cross-coupling reactions. Like their symmetrical analogues they displayed high activity in the coupling of phenyl boronic acid with p-tolylchloride but their performance remained slightly inferior to that of the related, symmetrical Et/Et complex 5h.
- Teci, Matthieu,Brenner, Eric,Matt, Dominique,Gourlaouen, Christophe,Toupet, Loic
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p. 12251 - 12262
(2014/08/05)
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- KINASE INHIBITORS AND METHOD OF TREATING CANCER WITH SAME
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The present teachings provide a compound represented by structural formula (I): or a pharmaceutically acceptable salt thereof. Also described are pharmaceutical compositions and methods of use thereof.
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Paragraph 0240
(2014/02/15)
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- Functionalized α-bromocyclopropylmagnesium bromides: Generation and some reactions
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Functional derivatives of gem-dibromocyclopropanes (ethers and esters of gemdibromocyclopropylmethanol, 2,2-dibromocyclopropanecarboxylic acids and their esters) undergo partial hydrodebromination at the treatment with isopropyl magnesium bromide (3-6 mol-equiv) in THF and then in methanol at -60°C affording the corresponding monobromides in 64-95% yields. The addition of nonsolvated magnesium bromide to the reaction mixture results in the considerable reduction of the amount of the Grignard reagent (from 6 to 3 mol-equiv). This allows achieving the partial hydrodebromination of 2,2-dibromocyclopropanecarboxylic acids. Pleiades Publishing, Ltd., 2013.
- Bolesov,Solov'eva,Baird
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p. 1580 - 1589
(2014/02/14)
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- Enantioselective copper-catalysed allylic alkylation of cinnamyl chlorides by Grignard reagents using chiral phosphine-phosphite ligands
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The copper(I)-catalysed SN2'-type allylic substitution of E-3-aryl-allyl chlorides (cinnamyl chlorides) using Grignard reagents represents a powerful method for the synthesis of compounds carrying a benzylic stereocentre. By screening a small library of modular chiral phosphine-phosphite ligands a new copper(I)-based catalyst system was identified which allows the performance of such reactions with exceptional high degrees of regio- and enantioselectivity. Best results were obtained using TADDOLderived ligands (3 mol%), copper(I) bromide?dimethyl sulfide (CuBr?SMe2) (2.5 mol%) and methyl tert-butyl ether (MTBE) as a solvent. Various (1- alkyl-allyl)benzene derivatives were prepared with up to 99% ee (GC) in isolated yields of up to 99%. In most cases the product contained less than 3% of the linear regioisomer (except for ortho-substituted substrates). Both electron-rich and electron-deficient cinnamyl chlorides were successfully employed. The absolute configuration of the products was assigned by comparison of experimental and calculated CD spectra. The substrates were prepared from the corresponding alcohols by reaction with thionyl chloride. Initially formed mixtures of regioisomeric allylic chlorides were homogenised by treatment with CuBr?SMe2 (2.5 mol%) in the presence of triphenyl phosphine (PPh3) (3 mol%) in MTBE at low temperature to give the pure linear isomers. In reactions with methylmagnesium bromide (MeMgBr) an ortho-diphenylphosphanyl-arylphosphite ligand with an additional phenyl substituent in ortho'-position at the aryl backbone proved to be superior. In contrast, best results were obtained in the case of higher alkyl Grignard reagents (such as ethyl-, n-butyl-, isopropyl-, and 3-butenylmagnesium bromides) with a related ligand carrying an isopropyl substituent in ortho'-position. The method was tested on a multimmol scale and is suited for application in natural product synthesis.
- Loelsberg, Wibke,Ye, Shute,Schmalz, Hans-Guenther
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supporting information; experimental part
p. 2023 - 2031
(2010/10/21)
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- PROCESS FOR PRODUCING EPOXYTRIAZOLE COMPOUND AND INTERMEDIATE THEREFOR
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The present invention provides a compound of the formula (I); wherein Ar represents difluorophenyl group, which is useful as an intermediate in a process for producing an epoxytriazole compound of the formula (VII); wherein Ar represents difluorophenyl group, which is a synthetic intermediate of antifungal agents. The present invention also provides a process for producing a compound of the formula (VII) which comprises epoxydation step, deprotection step, reaction step with a compound represented by RSO2X, and reaction step with 1,2,4-triazole; or comprises epoxydation step, reaction step with 1,2,4-triazole, deprotection step, reaction step with a compound represented by RSO2X and treatment step by a base.
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Page/Page column 23
(2010/11/23)
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- Method for producing alkyl-bridged ligand systems and transition metal compounds
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The invention relates to a method for producing highly substituted alkyl-bridged ligand systems on the basis of indene derivatives and transition metal compounds. Said alkyl-bridged ligand systems can be obtained in high yields using this method.
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- Substituted oxygen alicyclic compounds, including methods for synthesis thereof
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The invention provides new methods for preparation of cyclic oxygen compounds, including 2,5-disubstituted tetahydrofurans, 2,6-disubstituted tetrahydropyrans, 2,7-disubstituted oxepanes and 2,8-oxocanes. The invention also provides new cyclic oxygen compounds and pharmaceutical compositions and therapeutic methods that comprise such compounds.
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- An ESR and HPLC-EC assay for the detection of alkyl radicals
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The correlation of lipid peroxidation with release of alkanes (RH) is considered a noninvasive method for the in vivo evaluation of oxidative stress. The formation of RH is believed to reflect a lipid hydroperoxide (LOOH)-dependent generation of alkoxyl radicals (LO·) that undergo β-scission with release of alkyl radicals (R·). Alternatively, R· could be spin-trapped with a nitrone before the formation of RH and analyzed by ESR. Extracts from the liver and lung of CCl4- and asbestos-treated rats that were previously loaded with nitrones exhibited ESR spectra suggesting the formation of iso-propyl, n-butyl, ethyl, and pentyl radical-derived nitroxides. In biological systems, various nitroxides with indistinguishable ESR spectra could be formed. Hence, experiments with N-tert-butyl-α-phenylnitrone (PBN) for spin trapping of R· were carried out in which the nitroxides formed were separated and analyzed by HPLC with electrochemical detection (EC). The C1-5 homologous series of PBN nitroxides and hydroxylamines were synthesized, characterized by ESR, GC-MS, and HPLC-EC, and used as HPLC standards. For in vivo generation and spin trapping of R·, rats were loaded with CCl4 and PBN. The HPLC-EC chromatograms of liver extracts from CCl4-treated rats demonstrated the formation of both the nitroxide and hydroxylamine forms of PBN/·CCl3, as well as the formation of a series of unidentified PBN nitroxides and hydroxylamines. However, formation of PBN adducts with retention times similar to these of the PBN/C2-5 derivatives was not observed. In conclusion, we could not correlate the production of PBN-detectable alkyl radicals with the reported CCl4-dependent production of C1-5 alkanes. We speculate that the major reason for this is the low steady-state concentrations of R· produced because only a small fraction of LO· undergo β-scission to release R·.
- Novakov,Feierman,Cederbaum,Stoyanovsky
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p. 1239 - 1246
(2007/10/03)
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- On the mechanism of titanium-catalyzed cyclopropanation of esters with aliphatic organomagnesium compounds. Deuterium distribution in the reaction products of (CD3)2CHMgBr with ethyl 3-chloropropionate in the presence of titanium tetraisopropoxide
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The reaction of (CD3)2CHMgBr with ethyl 3-chloropropionate in the presence of catalytic amounts of Ti(OPr1)4 results in (E)-1-(2-chloroethyl)-3,3-dideuterio-2-trideuteriomethylcyclopropanol and (CD3)2CDH, identified by mass spectrometry. The reaction mechanism is discussed.
- Epstein,Savchenko,Kulinkovich
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p. 378 - 380
(2007/10/03)
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- Nodulisporic acid derivatives
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The present invention relates to novel nodulosporic acid derivatives, which are acaricidal, antiparasitic, insecticidal and anthelmintic agents.
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- Method for inhibiting angiogenesis using squalamine and squalamine steroid derivatives
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A method of inhibiting angiogenesis in a patient includes administering to the patient an effective amount of squalamine or a pharmaceutically acceptable salt of squalamine. Alternatively, a compound according to the following Formula (III) (or a pharmaceutically acceptable salt thereof) can be administered: STR1 wherein Z5 is α-H or β-H; each of the substituents Z7 is selected from the group of --H, --OH, --SH, --NH2, --F, --(C1 -C3)-alkyl, and --(C1 -C3)-alkoxy; and one of the substituents Z12 is --H and the other is --H or --OH. X' is a polyamine side chain of the formula --X1 --(CH2)p --X2 --(CH2)q --N(RII)(RIII), wherein one of X1 and X2 is --N(RIV) and the other is selected from the group of --N(RV), --O, --S, and --CH2. RIV and RV are each --H or --(C1 -C3)-alkyl, p and q are each an integer of from 0 to 5 (but both are not 0). RII and RIII in the formula for X' are each --H, --(C1 -C3)-alkyl, or --(CH2)r --N(R10)(R11) wherein r is an integer from 2 to 5 and R10 and R11 are each --H or --(C1 -C3)-alkyl. R' in Formula (III) is --H or --(C1 -C3)-alkyl, and Y' is --(C1 -C10)-alkyl, unsubstituted or substituted with --CO2 H, --OH, --NH--SO2 CF3, --SO3 H, --PO3 H2, --OSO3 H, --CF3, --F, STR2
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- Nature of Organic Radical in Hydrocarbon Halide and Character of Its Adsorption on Magnesium Surface during Oxidation of the Metal
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Adsorption of various hydrocarbon bromides on magnesium surface from a mixture of diethyl ether and benzene during magnesium oxidation was studied. The character of adsorption, the reaction rate, and the yields of the Grignard reagents are determined by the structure of the organic radical in the oxidant molecule.
- Maslennikov,Spirina
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p. 1876 - 1877
(2007/10/03)
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- Steroid derivatives, pharmaceutical compositions containing them, and their use as antibiotics or disinfectants
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Compounds having a broad range of antimicrobial activity generally have a structure including asteroid nucleus with a cationic, preferably polyamine, side chain (X) and an anionic side chain (Y). The invention is also directed to compounds of the Formula III: STR1 preferably where the steroid ring nucleus is saturated; the steroid ring substituent Z5 is α-H; one Z7 is β-H and the other is α-H or α-OH; both substituents Z12 are hydrogen; X' is a polyamine side chain of the formula --NH--(CH2)p --NH--(CH2)q --N(RII)(RIII) where p and q are each independently 3 or 4, and RII and RIII are each independently hydrogen or methyl; R' is methyl; and Y' is (C1 -C10)-alkyl substituted with a group such as --CO2 H or --SO3 H.
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- A HIGHLY EFFICIENT SYNTHETIC ROUTE TO KETONES THROUGH SEQUENTIAL COUPLING REACTIONS OF GRIGNARD REAGENTS WITH S-PHENYL CARBONOCHLORODITHIOATE IN THE PRESENCE OF NICKEL OR IRON CATALYSTS
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The sequential coupling reactions of Grignard reagents with S-phenyl carbonochloridothioate in the presence of nickel(II) or iron(III) catalysts provides a very mild and straightforward route to symmetrical and unsymmetrical aliphatic and aromatic ketones.
- Cardellicchio, C.,Fiandanese, V.,Marchese, G.,Ronzini, L.
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p. 3595 - 3598
(2007/10/02)
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- Thermochemical Bond Dissociation Energies of Carbon-Magnesium Bonds
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The heats of formation of 29 alkylmagnesium bromides, isobutyl bromide, and neopentyl bromide have been determined, and bond dissociation energies have been derived for the Grignard reagents.For saturated alkyl derivatives the C-Mg bond strength decreases with an increasing number of β-hydrogens in the series methyl, neopentyl, isobutyl, butyl, ethyl, 1-ethylpropyl, 1-methylpropyl, isopropyl, and t-butyl.Bonding in alkyl bromides and alkylmagnesium bromides is discussed.
- Holm, Torkil
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p. 464 - 467
(2007/10/02)
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