- Boryl-dihydrideborate osmium complexes: Preparation, structure, and dynamic behavior in solution
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The metal fragment Os(CO)(PiPr3)2 stabilizes boryl-dihydrideborate species, which can be viewed as snapshots of states of B-H oxidative addition of a R2BH molecule and frustrated B-H bond activation of a second one. Complex OsH2(η2-CH2=CHEt)(CO)(PiPr3)2 (2) shows a tendency to dissociate the olefin. The resulting dihydride OsH2(CO)(PiPr3)2 (3) rapidly coordinates catecholborane (HBcat) and pinacolborane (HBpin) to give the corresponding σ-borane derivatives OsH2(η2-HBR2)(CO)(PiPr3)2 (BR2 = Bcat (4), Bpin (5)). Complex 4 reacts with a second molecule of HBcat to release H2 and to afford the octahedral boryl dihydride borate derivative Os(Bcat)(κ2-H2Bcat)(CO)(PiPr3)2 (6), which undergoes a thermally activated Bcat site exchange process in solution. Borane displaces catecholborane from the dihydride-borate of 6 to generate the boryl-tetrahydrideborate Os(Bcat)(κ2-H2BH2)(CO)(PiPr3)2 (7). This compound and the Bpin counterpart Os(Bpin)(κ2-H2BH2)(CO)(PiPr3)2 (8) have also been prepared by reaction of the corresponding Os(BR2)Cl(CO)(PiPr3)2 with Na[BH4].
- Esteruelas, Miguel A.,López, Ana M.,Mora, Malka,O?ate, Enrique
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- New economical, convenient procedures for the synthesis of catecholborane
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Catecholborane was conveniently synthesized by the reaction of tri-O-phenylene bis-borate (2) with diborane in triglyme or tetraglyme at moderate temperatures (70-80 °C). The product, catecholborane, can be distilled out in 85% yield with >97% purity. The
- Kanth, Josyula V.B.,Periasamy, Mariappan,Brown, Herbert C.
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- Kinetics of the reduction of pinacolone by borane-dimethyl sulfide and catecholborane in THF
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The kinetics of the reduction of the ketone, pinacolone by borane-dimethyl sulfide and catecholborane have been investigated in tetrahydrofuran. Both overall reactions are composed of several subsequent and in part competing reactions. The use of commerci
- Eckhardt, Conrad,Jockel, Holger,Schmidt, Reinhard
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- Synthesis of Unsymmetrical Diboron(5) Compounds and Their Conversion to Diboron(5) Cations
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Reaction of the bis-catecholatodiboron-NHC adducts B2Cat2(NHC) (NHC = IMe (tetramethylimidazol-2-ylidene), IMes (1,3-dimesitylimidazol-2-ylidene), IDIPP (1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene)) with BCl3 results in the replacement of the catecholato group bound to the four-coordinate boron atom with two chlorides to yield diboron(5) Lewis acid-base adducts of the formula CatBBCl2(NHC). These compounds are precursors to diboron(5) monocations, accessed by adding AlCl3 or K[B(C6F5)4] as halide abstraction agents in the presence of a Lewis base. The substitution of the chlorides of CatBBCl2(NHC) for hydrides was achieved using Bu3SnH and a halide abstracting agent to form 1,1-dihydrodiboron(5) compounds, CatBBH2(NHC). Attempts to generate diboron(4) monocations of formula [CatBB(Y)(NHC)]+ (Y = Cl, H) led to the rapid formation of CatBY.
- Cid, Jessica,Hermann, Alexander,Radcliffe, James E.,Curless, Liam D.,Braunschweig, Holger,Ingleson, Michael J.
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- Trans -2 - substituted cycloalkyl three fluoro potassium borate synthesis method (by machine translation)
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The invention discloses trans - 2 - substituted cyclohexyl three fluoro potassium borate synthesis method, which belongs to the field of organic synthesis. From the cyclic ketone starting curing and reagent or lithium reagent addition subsequently dehydrated and gets substituted alkenes, subsequently with the catechol borane or after aminol borane addition reaction, fluorine hydride potassium direct quenching treatment to obtain trans - 2 - substituted cyclohexyl three fluoro potassium borate, the catechol borane to obtain the racemate product, [...] photoinitiators enantiomerically pure product. The method has low cost, convenient source of raw materials, the operation is simple, and has industrial amplifying of the prospect. (by machine translation)
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Paragraph 0022
(2019/04/04)
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- Synthesis of catechol-, pinacol-, and neopentylglycolborane through the heterogeneous catalytic B-B hydrogenolysis of diboranes(4)
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A new synthetic approach to hydroboranes catechol-, pinacol-, and neopentylglycolborane has been developed. Starting from diboranes(4) B 2cat2, B2pin2, or B 2neop2, the respective boranes were obtained by heterogeneously catalyzed cleavage of the B-B bond in the respective diboranes with hydrogen. Group10 metals were found to be effective catalysts for this reaction. Copyright
- Braunschweig, Holger,Guethlein, Frank,Mailaender, Lisa,Marder, Todd B.
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p. 14831 - 14835
(2013/11/06)
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- PYRIDO[4,3-B]INDOLE AND PYRIDO[3,4-B]INDOLE DERIVATIVES AND METHODS OF USE
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This disclosure is directed to pyrido[4,3-b]indole and pyrido [3,4-b] indole derivatives. Pharmaceutical compositions comprising the compounds are also provided, as are methods of using the compounds in a variety of therapeutic applications, including the treatment of a cognitive disorder, psychotic disorder, neurotransmitter-mediated disorder and/or a neuronal disorder.
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Page/Page column 101
(2011/09/19)
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- Spiroborate catalyzed reductions with N,N-diethylaniline borane
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Reduction of esters, amides, and ketones by N,N-diethylaniline borane is accelerated by catalysts derived from spiroborate complexes. Esters are reduced at ambient temperature in less than 4 h with this amine borane and 5 mol % spiroborate 6. Functional group selectivity shows ketone and tertiary amide reduction is faster than ester or nitrile reduction.
- Coleridge, Brian M.,Angert, Thomas P.,Marks, Lucas R.,Hamilton, Patrick N.,Sutton, Christopher P.,Matos, Karl,Burkhardt, Elizabeth R.
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supporting information; experimental part
p. 5973 - 5976
(2010/11/21)
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- BOOTSTRAP SYNTHESIS OF BORANES
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Metal hydride materials react with BZ3 compounds in the presence of ligand to form BH3-L compounds. A compound of the formula HBZ2 is prepared from a compound of the formula BZ3 by reacting a first amount of a compound of the formula HBZ2 with a metal hydride material "MH" and a compound "L" to form a material of the formula BH3-L, and then reacting the BH3-L thus formed with a compound of the formula BZ3 to form HBZ2 in a second amount greater than the first amount of HBZ2. Z is selected from alkoxy, aryloxy, amido, arylamido, doubly substituted alkoxy, doubly substituted aryloxy, doubly substituted amido, doubly substituted arylamido, alkoxy-amido, and aryloxy-arylamido. When Z is bidentate, then HBZ2 has a ring structure. "L" is selected from ethers, aromatic ethers, amines, aromatic amines, heterocyclic nitrogen compounds, sulfides, aromatic sulfides, and heterocyclic sulfur compounds. "L" becomes a ligand in the BH3-L material.
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Page/Page column 13
(2008/06/13)
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- Preparation of (E)-1-alkenylboronic acid pinacol esters via transfer of alkenyl group from boron to boron
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Two synthetic routes to (E)-1-alkenylboronic acid pinacol esters 3 were investigated. Hydroboration of 1-alkynes 1 with 1,3,2-benzodioxaborole (catecholborane), in situ generated by the reaction of BH3 in THF with catechol, proceeded in the presence of a catalytic amount of dicyclohexylborane in THF at room temperature to give the corresponding (E)-1-alkenylboronic acid catechol esters 2. Treatment of the resultant esters 2 with 2,3-dimethyl-2,3-butanediol (pinacol) easily afforded the desired products 3, which are insensitive to air, moisture and chromatography, in good to high overall yields. The sequential reaction is a highly efficient route to 3 from BH3 in THF in a one-pot manner. Alternatively, hydroboration of 1 with 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (pinacolborane) was achieved in the presence of a catalytic amount of dicyclohexylborane at room temperature under neat conditions to afford the corresponding products 3 directly in good to excellent yields. This route is extremely efficient and environmentally benign from the viewpoints of making good use of pinacolborane and of using no solvent, and is capable of using a variety of alkynes 1 including functionalized ones such as HCCCH2Cl and HCCCH2OTHP.
- Shirakawa, Kazuya,Arase, Akira,Hoshi, Masayuki
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p. 1814 - 1820
(2007/10/03)
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- Sodium Hydro(isothiocyanato)borates: Synthesis and Structures
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Sodium thiocyanate reacts in THF solution with 18-crown-6 to give the molecular compound Na(18-crown-6)(THF)NCS (3) with the N atom of the NCS anion oriented towards Na1+. The same reaction with 15-crown-5 yields the ion pair Na(15-crown-5)NCS (4). In contrast, Na(NCS)(py)4, obtained by treating a solution of Na(H3BNCS) in THF with pyridine, yields Na(py)4(NCS) (5), which has a chain structure with hexacoordinate Na atoms coordinated to five N atoms and an S atom. Na(NCS) in THF adds 1 equiv. of BH3 to give Na(H3BNCS)*nTHF. Addition of 18-crown-6 to this solution yields crystals of the salt [Na(18-crown-6)(THF)2][H3BNCS] (1), as shown by X-ray crystallography. Both the cation and the anion show site disorder. However, when 15-crown-5 is used for complexation, the salt [Na(15-crown-5)(THF)][H3BNCS] (2) can be isolated. Its anion shows an almost linear B-N-C-S unit. Only a mixture of (catecholato)(isothiocyanato)borates results on treating Na(NCS) in THF with catecholborane. However, the borate Na[catB(NCS)2] is readily formed by adding Na(NCS) to B-(isothiocyanato)catecholborane. Single crystals of this compound were obtained as the salt [Na(18-crown-6)(THF)2][catB(NCS)2] (6). On the other hand, the reaction of Na(NCS) with 9-borabicyclo[3.3.1]nonane (9-BBN) in THF yields Na[(9-BBN)NCS]*nTHF, and, on addition of 18-crown-6, the complex [Na(18-crown-6)(THF)2][(9-BBN)NCS] was isolated. Suitable crystal for X-ray structure determination were, however, only obtained by crystallization from tetrahydropyran. This solvate has the rather unusual structure [Na(18-crown-6)(thp)2][{(9-BBN)NC}2Na(thp)4] (8). The sodiate anion has an Na atom coordinated by two S and four O atoms. DFT calculations support these experimental results: The (isothiocyanato)borates are more stable than the thiocyanato isomers. For the latter a bent structure of the B-S-C-N unit with a B-S-C bond angle of 105.7 deg is predicted.
- Noeth, Heinrich,Warchhold, Marcus
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p. 1115 - 1124
(2007/10/03)
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- Synthesis and structures of some trisorganylstannyl boranes and triorganylstannyl borates
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New stannylboranes were prepared from tetramethylpiperidino dichloroborane or B-bromo-pentamethylborazine with lithium triorganylstannides LiSnR3. Only double stannylation was possible with tmpBCl2 and LiSnMe3, while tmpBCl(SnPh3) was obtained by employing LiSnPh3. This chloride reacted with LiGePh3 to the stannyl germyl borane tmpB(GePh3)(SnPh3). On the other hand, PhMeNBCl2 and an excess of LiSnMe3 gave the borate Li[B(NMePh)(SnMe3)3], which was isolated as a solvate with 4 molecules of THF. The compound is present in the solid state as a solvent separated ion pair. The borate Li(H3BSnMe3) · 2 THF is dimeric in the solid state. Dimerization occurs via two single Li-H-B bridges and a Li-H(B)-Li bridge. The B-Sn bonds in the borates are practically of the same lengths as those in the boranes. In solution all BH bonds of this trihydridoborate are equivalent. Wiley-VCH Verlag GmbH, 2001.
- Habereder, Tassilo,Noeth, Heinrich
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p. 789 - 796
(2008/10/08)
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- Economical and convenient procedures for the synthesis of catecholborane
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New, economical and convenient procedures for the preparation of catecholborane in high chemically pure form using tri-O-phenylene bis borate readily prepared from the reaction of catechol with boric acid, and diborane or borane-Lewis base complexes.
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- Group 5 metallocene complexes as models for Metal-Mediated hydroboration: Synthesis of a reactive borane adduct, endo-Cp*2Nb(H2BO2C6H4), via hydroboration of coordinated olefins
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The olefin complexes Cp*2M(CH2=CH(R))(H) (R = H (1), CH3 (2); M = Nb (a), Ta (b)) react cleanly with catecholborane (HBCat) and HBO2C6H3-4-(t)Bu (HBCat') to give Cp*2M(H2/s
- Lantero, Dean R.,Ward, Donald L.,Smith III, Milton R.
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p. 9699 - 9708
(2007/10/03)
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- Contribution to the chemistry of boron. 237. Bis(benzo-1,3,2-dioxaborolanyl)oxide and 2-(o-Hydroxyphenoxy)-benzo-1,3,2-dioxaborolane. Precursors for the synthesis of catecholborane (benzo-1,3,2-dioxaborolan)
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The title compounds have been prepared from B(OH)3 with catechol using different stoichiometries and were characterized by NMR spectroscopy and X-ray structure analysis. Bis(benzo-1,3,2-dioxoborolanyl)oxide, 3, has C2 point group symmetry with a wide B-O-B bond angle (135.9°) in contrast to the new catecholester of boric acid, 2-(o-hydroxyphenoxy)-benzo-1,3,2-dioxaborolane, 4, which shows an almost planar molecular structure. These molecules form infinite chains in the solid state. 2-Hydroxy-1,3,2-dioxaborolane 6 crystallizes as a OH ? O bridged dimer. 3 proved to be a good starting material for the preparation of catecholborane (C6H4O2)BH.
- Lang, Andreas,Knizek,No?th, Heinrich,Schur,Thomann, Martina
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p. 901 - 907
(2008/10/09)
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- Convenient method for the preparation of catecholborane and promotion of the formation of alkenyl catecholborane using BH3 complexes
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Catecholborane is prepared in benzene by passing B2H6, generated from I2/NaBH4, through a suspension of catechol at 25 deg C.The reagent prepared in this way is used for hydroboration-oxidation of representative alkenes and alkynes at 80 deg C.Hydroboration of 1-alkynes followed by iodination with I2/NaOH gives the corresponding trans-1-alkenyl iodides in 70-72percent yield.The alkenyl catecholboranes can be prepared at 25 deg C by performing the reaction in the presence of 10 molepercent of H3B:N(C2H5)2Ph or H3B:THF.The reaction is believed to go through hydroboration of thealkynes by borane followed by exchange with catecholborane.Studies of the preparation of dialkylphenoxyboranes and alkenyldiphenoxyboranes through hydroboration of 1-decene and 1-decyne by use of H3B:N(C2H5)2Ph and phenol are also reported.
- Suseela, Y.,Periasamy, M.
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- Catalytic Effect of a BH3:N,N-Diethylaniline Complex in the Formation of Alkenyl Catecholboranes from Alk-1-ynes and Catecholborane
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Alkenyl catecholboranes are readily formed by the reaction of catecholborane and alk-1-ynes at 25 deg C, in the presence of 10 molpercent of a BH3:N,N-diethylaniline complex, via a hydroboration-alkenyl transfer mechanism.
- Suseela, Yantrapragada,Prasad, A. S. Bhanu,Periasamy, Mariappan
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p. 446 - 447
(2007/10/02)
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- Process for producing catecholborane
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A process is described in which catecholborane is produced by a reaction of a phenolic compound with a boron hydride in a solvent. Tris(catecholato)bisborane, i.e. the ester of boric acid and catechol, is reacted with an alkali metal-boron hydride in an aliphatic ether. A lithium halide is suitably used too, where sodium-boron hydride or potassium-boron hydride is employed. In a preferred embodiment, the reaction is carried out in conjunction with an activating grinding operation.
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- Contributions to the Chemistry of Boron. Part 160. A Convenient Synthesis of Catecholatoborane and Diborane
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Catecholatoborane is formed in high yield (> 75percent) by ball milling NaBH4 and 2,2'-o-phenylenedioxybis(1,3,2-benzodioxaborole) in diethyl ether in the presence of small amounts of LiCl.It also results quantitatively from the first two components in di
- Maennig, Detlef,Noeth, Heinrich
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p. 1689 - 1692
(2007/10/02)
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