- Borinic acid catalysed peptide synthesis
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The catalytic synthesis of peptides is a major challenge in the modern organic chemistry hindered by the well-established use of stoichiometric coupling reagents. Herein, we describe for the first time that borinic acid is able to catalyse this reaction under mild conditions with an improved activity compared to our recently developed thiophene-based boronic acid. This catalyst is particularly efficient for peptide bond synthesis affording dipeptides in good yields without detectable racemization.
- El Dine, Tharwat Mohy,Rouden, Jacques,Blanchet, Jér?me
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supporting information
p. 16084 - 16087
(2015/11/10)
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- Cross-coupling of diarylborinic acids and anhydrides with arylhalides catalyzed by a phosphite/N-heterocyclic carbene co-supported palladium catalyst system
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A highly efficient cross-coupling of diarylborinic acids and anhydrides with aryl chlorides and bromides has been effected by using a palladium catalyst system co-supported by a strong σ-donor N-heterocyclic carbene (NHC), N,N′-bis(2,6-diisopropylphenyl) imidazol-2-ylidene, and a strong π-acceptor phosphite, triphenylphosphite, in tert-BuOH in the present of K3PO4·3H2O. Unsymmetrical biaryls with a variety of functional groups could be obtained in good to excellent yields using as low as 0.01, 0.2-0.5, and 1 mol % palladium loadings for aryl bromides and activated and deactivated aryl chlorides, respectively, under mild conditions. A ligand synergy between the σ-donor NHC and the π-acceptor phosphite in the Pd/NHC/P(OPh)3 catalytic system has been proposed to be responsible for the high efficacy to arylchlorides in the cross-coupling. A scalable and economical process has therefore been developed for synthesis of Sartan biphenyl from the Pd/NHC/P(OPh)3 catalyzed cross-coupling of di(4-methylphenyl)borinic acid with 2-chlorobenzonitrile.
- Chen, Xiaofeng,Ke, Haihua,Chen, Yao,Guan, Changwei,Zou, Gang
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p. 7572 - 7578
(2012/10/29)
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- 2-(N-Alkylamino)-1-(trifluoroacetimidoyl)vinyl ketone derivatives as potential reagents in heterocyclic synthesis
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A reaction of 3-acetyl-4-amino-5,5,5-trifluoropent-3-en-2-one diphenylboron chelate and ammonia or primary amines affords 4-amino-or 4-alkylamino-3- trifluoroacetimidoylpent-3-en-2-ones, new reagents which can be used for the synthesis of pyrimidines with trifluoromethyl group.
- Vasil'Ev,Prezent,Ignatenko,Dorokhov
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experimental part
p. 2359 - 2363
(2010/02/16)
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- 2-Aminoethoxydiphenyl borate as a prototype drug for a group of structurally related calcium channel blockers in human platelets
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We have synthesized a series of 2-aminoethoxydiphenyl borate (2-APB, 2,2-diphenyl-1,3,2-oxazaborolidine) analogs and tested their ability to inhibit thrombin-induced Ca2+ influx in human platelets. The analogs were either synthesized by adding various substituents to the oxazaborolidine ring (methyl, dimethyl, tert-butyl, phenyl, methyl phenyl, and pyridyl) or increasing the size of the oxazaborolidine ring to seven- and nine-membered rings. NMR analysis of the boron-containing analogs suggests that each of them exist as a ring structure through the formation of an N→B coordinate bond (except for the hexyl analog). The possibility that these boron-containing compounds formed dimers was also considered. All compounds dose-dependently inhibited thrombin-induced Ca2+ influx in human platelets, with the 2,2-diphenyl-1,3,2-oxazaborolidine-5-one derivative having the weakest activity at 100 μM, whereas the (S)-4-benzyl and (R)-4-benzyl derivatives of 2-APB were approximately 10 times more potent than the parent 2-APB. Two nonboron analogs (3-methyl and 3-tert-butyl 2,2-diphenyl-1,3-oxazolidine) were synthesized; they had approximately the same activity as 2-APB, and this implies that the presence of boron was not necessary for inhibitory activity. All of the compounds tested were also able to inhibit thrombininduced calcium release. We concluded that extensive modifications of the oxazaborolidine ring in 2-APB can be made, and Ca2+-blocking activity was maintained. Copyright
- Dobrydneva, Yuliya,Abelt, Christopher J.,Dovel, Beth,Thadigiri, Celina M.,Williams, Roy L.,Blackmore, Peter F.
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p. 247 - 256
(2007/10/03)
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- Synthesis and anticoccidial activity of some azacyclo organoborinates
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A series of azacyclo organoborinates derivatives of piperidinyl and pyridinyl alcohols were prepared and their anticoccidial activity was tested in vitro assay system. Among them, di(4-chlorophenyl)(2-piperidinylmethoxy-O,N)boron, di(3-trifluoromethylphenyl)(2-piperidinylmethoxy-O,N)boron, di(3-trifluoromethylphenyl)(2-pyridinylmethoxy-O,N)boron, and di(3-trifluoromethylphenyl)(2-pyridinylethoxy-O,N)boron, showed moderate anticoccidial activity against Eimeria tenella.
- Tabuchi, Hitoshi,Kawaguchi, Harumoto,Taniguchi, Hisashi,Imazaki, Hideyuki,Hayase, Yoshio
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p. 1319 - 1326
(2007/10/03)
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- Trisubstituted silylalkyl 1,2,4-triazole and imidazole phenyl borane derivatives
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Trisubstituted silyalkyl 1,2,4-triazole and imidazole phenyl borane compounds having the formula: STR1 wherein n, X, R, R1, R2, R3, R4, and R5 are defined in the description, and processes and intermediates for the preparation thereof are disclosed. The compounds of Formula I are especially useful as agricultural fungicides.
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