- Preparation method of monohalogenated phenylboronic acid
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The invention relates to the technical field of chemical synthesis, and particularly discloses a preparation method of monohalogenated phenylboronic acid. The preparation method comprises the following steps of: by taking dihalogenated benzene as a raw material and a mixture of lithium salt and alkaline ionic liquid as a catalyst, carrying out Grignard exchange with R1MgCl to generate monohalogenated phenyl magnesium chloride, reacting with B (OR) 3 to generate monohalogenated phenyl borate, and hydrolyzing under acidic conditions to obtain monohalogenated phenylboronic acid. The HPLC (High Performance Liquid Chromatography) content of the monohalogenated phenylboronic acid prepared by the method is greater than 99.5%; the total yield of the product is greater than 80%, the contents of monohalogenated phenylboronic acid and phenyldiboronic acid impurities of another halogen are both less than 0.003%, the requirements of modern fine chemical synthesis are completely met, the raw materials are easily available, the operation is simple, the safety is high, and the industrial production of monohalogenated phenylboronic acid is realized.
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Paragraph 0066-0071
(2020/09/20)
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- Magnesium promoted autocatalytic dehydrogenation of amine borane complexes: A reliable, non-cryogenic, scalable access to boronic acids
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Owing to the unusual reactivity of dialkylamine-borane complexes, a methodology was developed to simply access boronic acids. The intrinsic instability of magnesium aminoborohydride was tweaked into a tandem dehydrogenation borylation sequence. Proceeding via an autocatalytic cycle, amineborane dehydrogenation was induced by a variety of Grignard reagents. Overall, addition of the organomagnesium species onto specially designed dialkylamine-borane complexes led to a variety of boronic acids in high yields. In addition, the reaction can be performed under Barbier conditions, on a large scale.
- Marciasini, Ludovic D.,Richard, Jimmy,Cacciuttolo, Bastien,Sartori, Guillaume,Birepinte, Melodie,Chabaud, Laurent,Pinet, Sandra,Pucheault, Mathieu
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p. 164 - 171
(2018/12/05)
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- Bedford-type palladacycle-catalyzed miyaura borylation of aryl halides with tetrahydroxydiboron in water
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A mild aqueous protocol for palladium catalyzed Miyaura borylation of aryl iodides, aryl bromides and aryl chlorides with tetrahydroxydiboron (BBA) as a borylating agent is developed. The developed methodology requires low catalyst loading of Bedford-type palladacycle catalyst (0.05 mol %) and works best under mild reaction conditions at 40 °C in short time of 6 h in water. In addition, our studies show that for Miyaura borylation using BBA in aqueous condition, maintaining a neutral reaction pH is very important for reproducibility and higher yields of corresponding borylated products. Moreover, our protocol is applicable for a broad range of aryl halides, corresponding borylated products are obtained in excellent yields up to 93% with 29 examples demonstrating its broad utility and functional group tolerance.
- Zernickel, Anna,Du, Weiyuan,Ghorpade, Seema A.,Sawant, Dinesh N.,Makki, Arwa A.,Sekar, Nagaiyan,Eppinger, J?rg
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p. 1842 - 1851
(2018/02/23)
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- Mechanistic insights into boron-catalysed direct amidation reactions
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The generally accepted monoacyloxyboron mechanism of boron-catalysed direct amidation is brought into question in this study, and new alternatives are proposed. We have carried out a detailed investigation of boron-catalysed amidation reactions, through study of the interaction between amines/carboxylic acids and borinic acids, boronic acids and boric acid, and have isolated and characterised by NMR/X-ray crystallography many of the likely intermediates present in catalytic amidation reactions. Rapid reaction between amines and boron compounds was observed in all cases, and it is proposed that such boron-nitrogen interactions are highly likely to take place in catalytic amidation reactions. These studies also clearly show that borinic acids are not competent catalysts for amidation, as they either form unreactive amino-carboxylate complexes, or undergo protodeboronation to give boronic acids. It therefore seems that at least three free coordination sites on the boron atom are necessary for amidation catalysis to occur. However, these observations are not consistent with the currently accepted 'mechanism' for boron-mediated amidation reactions involving nucleophilic attack of an amine onto a monomeric acyloxyboron intermediate, and as a result of our observations and theoretical modelling, alternative proposed mechanisms are presented for boron-mediated amidation reactions. These are likely to proceed via the formation of a dimeric B-X-B motif (X = O, NR), which is uniquely able to provide activation of the carboxylic acid, whilst orchestrating the delivery of the amine nucleophile to the carbonyl group. Quantum mechanical calculations of catalytic cycles at the B3LYP+D3/Def2-TZVPP level (solvent = CH2Cl2) support the proposal of several closely related potential pathways for amidation, all of which are likely to be lower in energy than the currently accepted mechanism.
- Arkhipenko, Sergey,Sabatini, Marco T.,Batsanov, Andrei S.,Karaluka, Valerija,Sheppard, Tom D.,Rzepa, Henry S.,Whiting, Andrew
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p. 1058 - 1072
(2018/02/07)
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- Importance of 5/6-aryl substitution on the pharmacological profile of 4?-((2-propyl-1H-benzo[d]imidazol-1-yl)methyl)-[1,1?-biphenyl]-2-carboxylic acid derived PPARγ agonists
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In this structure-activity relationship study, the influence of aryl substituents at position 5 or 6 on the pharmacological profile of the partial PPARγ agonist 4‘-((2-propyl-1H-benzo[d]imidazol-1-yl)methyl)-[1,1‘-biphenyl]-2-carboxylic acid was investigated. This lead was previously identified as the essential part of telmisartan to induce PPARγ activation. Para-OCH3-phenyl substitution strongly increased potency and efficacy independent of the position. Both compounds represent full agonists because of strong hydrophobic contacts with the amino acid Phe363 in the ligand binding domain. Partial agonists with higher potency than telmisartan or the lead were obtained with OH or Cl substituents at the phenyl ring. Molecular modeling suggested additional hydrogen or halogen bonds with Phe360 located at helix 7. It is assumed that these interactions fix helix 7, thereby promoting a partial agonist conformation of the receptor. The theoretical considerations correlate very well with the results from the luciferase transactivation assay using hPPARγ-LBD as well as those from a time-resolved fluorescent resonance energy transfer (TR-FRET) assay in which the coactivator (TRAP220, PGC-1α) recruitment and corepressor (NCoR1) release pattern was investigated.
- Obermoser, Victoria,Mauersberger, Robert,Schuster, Daniela,Czifersky, Monika,Lipova, Marina,Siegl, Monika,Kintscher, Ulrich,Gust, Ronald
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supporting information
p. 590 - 603
(2016/12/09)
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- Borinic Acid Catalysed Reduction of Tertiary Amides with Hydrosilanes: A Mild and Chemoselective Synthesis of Amines
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A reduction of various aryl, alkyl, and α,β-unsaturated amides with phenylsilane, catalysed by a borinic acid, is reported. The unprecedented reaction was carried out under very mild conditions and led to useful amines. Furthermore, the reaction tolerates a variety of functional groups. Initial investigations implicated that an intermediate diarylhydroborane is involved in the reaction mechanism.
- Chardon, Aurélien,Mohy El Dine, Tharwat,Legay, Rémi,De Paolis, Micha?l,Rouden, Jacques,Blanchet, Jér?me
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supporting information
p. 2005 - 2009
(2017/02/19)
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- NOVEL PI3K p110 INHIBITORS AND METHODS OF USE THEREOF
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The invention includes compositions that regulated PI3K p110 delta and are useful as an anti-viral therapy. The invention includes a method of inhibiting p110 delta, a component of PI3K p110 delta signaling pathway, or any combination thereof in a cell as
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Page/Page column 68
(2013/07/05)
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- Deprotection of pinacolyl boronate esters via hydrolysis of intermediate potassium trifluoroborates
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An efficient two-step procedure for the deprotection of pinacolyl organoboronate esters is described. Reaction with excess potassium hydrogen fluoride produces the corresponding stable, crystalline potassium organotrifluoroborate salts. Treatment of the trifluoroborates with either inorganic base or trimethylsilyl chloride and water affords the corresponding organoboronic acid in high yield.
- Yuen, Alexander K.L.,Hutton, Craig A.
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p. 7899 - 7903
(2007/10/03)
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- An improved protocol for the preparation of 3-pyridyl- and some arylboronic acids
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3-Pyridylboronic acid was prepared in high yield and bulk quantity from 3-bromopyridine via a protocol of lithium-halogen exchange and "in situ quench". This technique was further studied and evaluated on other aryl halides in the preparation of arylboronic acids.
- Li, Wenjie,Nelson, Dorian P.,Jensen, Mark S.,Hoerrner, R. Scott,Cai, Dongwei,Larsen, Robert D.,Reider, Paul J.
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p. 5394 - 5397
(2007/10/03)
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- Inhibitors of farnesyl protein transferase
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The present invention comprises benzodiazepine compounds having farnesyl transferase inhibitory activity.
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