4463-42-7Relevant articles and documents
A General C(sp3)-C(sp3) Cross-Coupling of Benzyl Sulfonylhydrazones with Alkyl Boronic Acids
Merchant, Rohan R.,Lopez, Jovan A.
supporting information, p. 2271 - 2275 (2020/03/13)
A general transition-metal-free cross-coupling between benzylic sulfonylhydrazones and 1°, 2°, or 3° alkyl boronic acids is reported. The base-promoted reaction is operationally simple and exhibits a broad substrate scope to forge a variety of alkyl-alkyl bonds, including between sterically encumbered secondary and tertiary sp3-carbons. The ability of this method to simplify retrosynthetic analysis is exemplified by the improved synthesis of multiple medicinally relevant scaffolds.
Transition-Metal-Free Three-Component Synthesis of Tertiary Aryl Amines from Nitro Compounds, Boronic Acids, and Trialkyl Phosphites
Roscales, Silvia,Csáky, Aurelio G.
supporting information, p. 111 - 117 (2019/11/16)
The synthesis of aromatic amines is of continuous interest in chemistry. An exceptionally versatile three-component reaction that directly transforms inexpensive nitro compounds, boronic acids, and trialkyl phosphites into tertiary aromatic amines has been realized. The reaction tolerates alkyl and aryl substituents on the nitro and boronic acid moieties, as well as functionalized phosphites. No transition-metal catalysis is required. The method is orthogonal to other classical metal-catalyzed syntheses since it tolerates the presence of halogens, and also permits the synthesis of functionalized compounds such as α-amino ester derivatives. (Figure presented.).
New statine intermediate, and using the same pitavastatin, rosuvastatin, and method of manufacturing cerivastatin [...]
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Paragraph 0107-0109, (2016/10/08)
The present invention provides a novel statin intermediate represented by chemical formula 1, and a method for producing pitavastatin, rosuvastatin, cerivastatin and fluvastatin by using the intermediate. (In chemical formula 1: n = 1, 2 or 3; Ar = a phenyl group or a phenyl group substituted with a C1-C4 alkyl or C6-C10 aryl, a naphthyl group or a naphthyl group substituted with a C1-C4 alkyl or C6-C10 aryl, or an anthracene group or an anthracene group substituted with a C1-C4 alkyl or C6-C10 aryl; and R1 is a C1-C8 alkyl, secondary alkyl, tertiary alkyl, aryl or aralkyl.)
Organotrifluoroborate hydrolysis: Boronic acid release mechanism and an acid-base paradox in cross-coupling
Lennox, Alastair J. J.,Lloyd-Jones, Guy C.
, p. 7431 - 7441 (2012/06/16)
The hydrolysis of potassium organotrifluoroborate (RBF3K) reagents to the corresponding boronic acids (RB(OH)2) has been studied in the context of their application in Suzuki-Miyaura coupling. The "slow release" strategy in such SM couplings is only viable if there is an appropriate gearing of the hydrolysis rate of the RBF3K reagent with the rate of catalytic turnover. In such cases, the boronic acid RB(OH)2 does not substantially accumulate, thereby minimizing side reactions such as oxidative homocoupling and protodeboronation. The study reveals that the hydrolysis rates (THF, H2O, Cs2CO 3, 55 °C) depend on a number of variables, resulting in complex solvolytic profiles with some RBF3K reagents. For example, those based on p-F-phenyl, naphthyl, furyl, and benzyl moieties are found to require acid catalysis for efficient hydrolysis. This acid-base paradox assures their slow hydrolysis under basic Suzuki-Miyaura coupling conditions. However, partial phase-splitting of the THF/H2O induced by the Cs2CO 3, resulting in a lower pH in the bulk medium, causes the reaction vessel shape, material, size, and stirring rate to have a profound impact on the hydrolysis profile. In contrast, reagents bearing, for example, isopropyl, β-styryl, and anisyl moieties undergo efficient "direct" hydrolysis, resulting in fast release of the boronic acid while reagents bearing, for example, alkynyl or nitrophenyl moieties, hydrolyze extremely slowly. Analysis of B-F bond lengths (DFT) in the intermediate difluoroborane, or the Swain-Lupton resonance parameter (R) of the R group in RBF3K, allows an a priori evaluation of whether an RBF3K reagent will likely engender "fast", "slow", or "very slow" hydrolysis. An exception to this correlation was found with vinyl-BF 3K, this reagent being sufficiently hydrophilic to partition substantially into the predominantly aqueous minor biphase, where it is rapidly hydrolyzed.
Observations on the deprotection of pinanediol and pinacol boronate esters via fluorinated intermediates
Inglis, Steven R.,Woon, Esther C. Y.,Thompson, Amber L.,Schofield, Christopher J.
supporting information; experimental part, p. 468 - 471 (2010/03/25)
(Chemical Equation Presented) Methods for the deprotection of pinanediol and pinacol esters of various boronic acids via fluoroborane intermediates were evaluated. Treatment of the boronate esters with potassium hydrogen difluoride normally gives trifluor
Electrosynthesis of benzylboronic acids and esters
Pintaric,Laza,Olivero,Du?ach
, p. 8031 - 8033 (2007/10/03)
A novel preparation of benzylboronic acids and esters is described by using an electrochemical reductive coupling reaction between benzylic halides and borating agents (trialkylborates or pinacolborane). The reaction is carried out at room temperature in DMF or THF with the use of a sacrificial magnesium anode in a single-compartment cell.
P1 Phenethyl peptide boronic acid inhibitors of HCV NS3 protease
Priestley,De Lucca, Indawati,Ghavimi, Bahman,Erickson-Viitanen, Susan,Decicco, Carl P.
, p. 3199 - 3202 (2007/10/03)
A series of peptide boronic acids containing extended, hydrophobic P1 residues was prepared to probe the shallow, hydrophobic S1 region of HCV NS3 protease. The p-trifluoromethylphenethyl P1 substituent was identified as optimal with respect to inhibitor potency for NS3 and selectivity against elastase and chymotrypsin.
Glass-catalyzed conversion of boronic esters of asymmetric diols to diol sulfites and amine complexes of boron halides
Matteson, Donald S.,Hiscox, William C.,Fabry-Asztalos, Levente,Kim, Gyung-Youn,Siems III, William F.
, p. 2920 - 2923 (2008/10/08)
Sterically hindered boronic esters of (R,R)-1,2-dicyclohexyl-1,2-ethanediol or pinanediol react with thionyl chloride and excess imidazole in acetonitrile on a borosilicate glass surface (but not on silica or sodalime glass) to form the corresponding cyclic sulfite of the diol and the easily separable organoborane derivative containing one boron-bound chloride and two imidazole groups, which may cross link with additional organoborane moieties to form oligomeric species. Other heterocyclic amines react similarly but usually less efficiently. With excess pyridine, the 1:1 complex PhBCl2(py) rapidly forms the 2:1 complex, PhBCl(py)2+Cl-. Hydrolysis of the amino boron chlorides to boronic acids in near neutral aqueous solution provides a mild process for the net hydrolysis of hindered boronic esters, many of which cannot be hydrolyzed by ordinary means, though yields were only 54-82%. The diol sulfites are stable toward water or aqueous acid but rapidly hydrolyzed by base to the diol and inorganic sulfite.
