- 4-Alkyl-3-azidomethyl-2-ethoxy-2,5-dihydro-5 H-1,2-oxaphosphole 2-Oxides: Synthesis and 1,3-Cycloaddition
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Starting from phosphorylated allenes, a three-steps synthesis of a new class of organic azides with a 1,2-oxaphospholene carbon skeleton has been developed. The series of obtained 4-alkyl-3-azidomethyl-2-ethoxy-2,5-dihydro-5H-1,2-oxaphosphole 2-oxides were utilized in the 1,3-cycloaddition with alkyl 2-[1-(propyn-2-yl)-1H-indol-3-yl]-2-oxoacetates for the synthesis of conjugates, which are potentially active cytostatics.
- Alekseychuk, Ekaterina P.,Anikina, Lada V.,Artyushin, Oleg I.,Brel, Valery K.
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supporting information
(2021/11/04)
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- Preparation method of high-purity butylphthalide
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The invention relates to a preparation method of high-purity butylphthalide. The preparation method comprises the following steps: (1) preparing n-butyl magnesium bromide; (2) synthesizing 2-valerylbenzoic acid; (3) synthesizing butylphthalide; and (4) refining the butylphthalide. Due to the adoption of the technical scheme, the preparation method has the advantages that the n-butyl magnesium bromide is used as an initiator in the step (1), so that the initiation condition is mild, and the safety performance is improved; and the initiation temperature is 38-42 DEG C, and the reaction temperature is only 48-52 DEG C, so that the temperature is easy to implement in the mass production process; the 2-valerylbenzoic acid is used as the raw material, and carbonyl is reduced in a sodium borohydride aqueous solution mode, so that explosion easily caused by a solid feeding mode is avoided, and production safety is guaranteed; and the butylphthalide is refined in a reduced pressure distillationmode, so that the method is simple and easy to implement, and the purity of the obtained high-purity butylphthalide reaches 100%. The synthesis process of butylphthalide is stable, the preparation process is mild and controllable, and the method is suitable for batch production.
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Paragraph 0035; 0037; 0039-0040
(2020/12/06)
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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 THE PREPARATION OF GRIGNARD COMPOUNDS
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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.
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Page/Page column 8
(2010/11/03)
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- CONTROL OF PARASITES IN ANIMALS BY THE USE OF IMIDAZO[1,2-B]PYRIDAZINE DERIVATIVES
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Novel imidazo[1,2-b]pyridazine compounds useful for controlling parasites in animals and methods of treatment of parasite infestation in animals using the compounds are disclosed. Formula (I).
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Page/Page column 29
(2008/06/13)
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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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- Diastereoselective reactions of δ-oxy-substituted allylic acetates with organocopper reagents
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SN2′ (γ) substitutions of δ-substituted allylic acetates with Grignard reagents and copper catalysts proceed with high diastereoselectivities. With benzyloxy, methoxymethoxy, and tert-butyldimethylsiloxy groups, reactions favor the anti-isomer with selectivities up to anti:syn = >99:1. With a hydroxyl group, selectivities are reversed and the syn-isomer is favored with selectivities up to anti:syn = 1:99.
- Belelie, Jennifer L.,Chong, J. Michael
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p. 3000 - 3006
(2007/10/03)
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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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- Tercyclohexyls
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Liquid-crystalline tercyclohexyls of the formula STR1 in which R is an alkyl group with 1-12 C atoms, in which one or two non-adjacent CH2 groups can be replaced by 0, X is --CN, --COOR1, --OOCR1, --COR1 or R1, and R1 is an alkyl group having 1-12 C atoms, with the proviso that in the case where X=R1 at least one CH2 group in the alkyl group R is replaced by 0, and useful in liquid-crystalline dielectrics.
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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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- IRON CATALYZED CROSS-COUPLING REACTIONS OF ACYL CHLORIDES WITH GRIGNARD REAGENTS. A MILD, GENERAL, AND CONVENIENT SYNTHESIS OF ALIPHATIC AND AROMATIC KETONES.
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Acyl chlorides couple with Grignard reagents at room temperature in the presence of catalytic amounts of tris(acetylacetonate)iron(III), Fe(acac)3.The reaction is general with respect to both reactants and provides a very mild and convenient method for the synthesis of aliphatic and aromatic ketones.
- Fiandanese, V.,Marchese, G.,Martina, V.,Ronzini, L.
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p. 4805 - 4808
(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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