74-94-2Relevant academic research and scientific papers
H/D scrambling in a chromium-catalyzed dehydrocoupling reaction of a borane-dimethylamine adduct
Kawano, Yasuro,Shimoi, Mamoru
, p. 11950 - 11955 (2017)
H/D scrambling took place in a chromium-catalyzed dehydrocoupling reaction of a deuterium-labeled borane-dimethylamine adduct. In the hydrogen elimination of BH3·NDMe2 (1a-dN), H2, HD and D2 were generated in 65:30:5 ratio, and 62% of deuterium atoms were incorporated into the major product, the dimethylaminoborane dimer. Proton and deuteron nuclei were thus concentrated into the evolved dihydrogen and aminoborane dimer, respectively. The mechanism of H/D scrambling is understood based on the reaction pathway of the dehydrocoupling of 1a, which was previously proposed based on DFT calculations. The H/D distribution in the products is explained by the energy difference according to the deuterated position in an intermediate of the dehydrocoupling reaction.
Pressure-induced structural changes in Methylamine borane and dimethylamine borane
Szilágyi, Petra á.,Hunter, Steven,Morrison, Carole A.,Tang, Chiu C.,Pulham, Colin R.
, p. 953 - 961 (2017)
Methylamine borane and dimethylamine borane have been studied under compression to 3 GPa using Raman spectroscopy and synchrotron powder X-ray diffraction. Both undergo reversible pressure-induced structural changes in this pressure range. The structural changes in the case of methylamine borane may be indicative of a second-order phase transition, taking place between ca. 0.8–1.2 GPa, which does not result in a change of space-group symmetry. In the case of dimethylamine borane, however, a reversible, reconstructive phase transition (monoclinic → orthorhombic) occurs below 0.7 GPa. This new high-pressure phase was successfully indexed, with a possible space group assignment of Pccn or Pbcn.
The reaction of mono- and dimethylamines with phosphorus trifluoride borane
Kodama,Parry
, p. 410 - 414 (1965)
The reaction between F3PBH3 and CH3NH2 gives [CH3NH]F2PBH3, [CH3NH]2FPBH3, or [CH3NH]3PBH3 depending upon the experimental conditions used. In no case was CH3NH2BH3 ever detected as a product of the methylamine reaction. On the other hand the reaction between F3PBH3 and (CH3)2NH gave good yields of (CH3)2NHBH3 under conditions comparable to those used for methylamine, and gave [(CH3)2N]F2PBH3 or [(CH3)2N]2FPBH3 under more severe conditions. Displacement reactions provide a basis for listing the above bases in order of increasing base strength using BH3 as a reference acid. The order is: F3P 3NH)F2P, [(CH3)2N]F2P 3)3, NH(CH3)2 3NH)2FP, [(CH3)2N]2FP. The results are discussed.
Preparation method of dimethylamine borane
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Paragraph 0032-0089, (2021/06/12)
The invention discloses a preparation method of dimethylamine borane, which comprises the following step of in a solvent, in the presence of monopotassium phosphate or phosphoric acid, reacting dimethylamine or hydrochloride thereof with BH4 ion-containing hydroboron to obtain the dimethylamine borane. The solvent is water or a mixed solvent of water and an organic solvent. The preparation method of dimethylamine borane disclosed by the invention is mild in condition, high in yield, high in purity and clean in reaction.
Visible light-mediated synthesis of amides from carboxylic acids and amine-boranes
Chen, Xuenian,Kang, Jia-Xin,Ma, Yan-Na,Miao, Yu-Qi
supporting information, p. 3595 - 3599 (2021/06/06)
Here, a photocatalytic deoxygenative amidation protocol using readily available amine-boranes and carboxylic acids is described. This approach features mild conditions, moderate-to-good yields, easy scale-up, and up to 62 examples of functionalized amides with diverse substituents. The synthetic robustness of this method was also demonstrated by its application in the late-stage functionalization of several pharmaceutical molecules.
Amine-boranes as Dual-Purpose Reagents for Direct Amidation of Carboxylic Acids
Choudhary, Shivani,Hamann, Henry J.,Ramachandran, P. Veeraraghavan
supporting information, (2020/11/13)
Amine-boranes serve as dual-purpose reagents for direct amidation, activating aliphatic and aromatic carboxylic acids and, subsequently, delivering amines to provide the corresponding amides in up to 99% yields. Delivery of gaseous or low-boiling amines as their borane complexes provides a major advantage over existing methodologies. Utilizing amine-boranes containing borane incompatible functionalities allows for the preparation of functionalized amides. An intermolecular mechanism proceeding through a triacyloxyborane-amine complex is proposed.
Method for the production of amine borane complex (by machine translation)
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Paragraph 0035; 0036, (2017/12/05)
The invention belongs to the technical field of material preparation, in particular relates to a method for the production of amine borane complex. This invention adopts the borane amine of the direct reaction of an inert gas stream, by regulating the ratio of the two, the need for further post-processing, to make the final product amine complex and offer. In the reaction process such impurity is introduced into the salt-free, does not use an organic solvent; the use of borohydride such as the reagent to produce the borane, for now the current system, can avoid direct operation of toxic gas borane. The method of the invention is simple in operation, the product has high purity, low cost, and can be continuous large-scale production. At the same time, the method and other way to produce the amine borane complex equipment compatible, production equipment by simple method can be used to adjust the production. (by machine translation)
Catalytic Dehydrocoupling of Amine-Boranes using Cationic Zirconium(IV)-Phosphine Frustrated Lewis Pairs
Metters, Owen J.,Flynn, Stephanie R.,Dowds, Christiana K.,Sparkes, Hazel A.,Manners, Ian,Wass, Duncan F.
, p. 6601 - 6611 (2016/10/14)
A series of novel, intramolecular Zr(IV)/P frustrated Lewis pairs (FLPs) based on cationic zirconocene fragments with a variety of ancillary cyclopentadienyl and 2-phosphinoaryloxide (-O(C6H4)PR2, R = tBu and 3,5-CF3-(C6H3)) ligands are reported and their activity as catalysts for the dehydrocoupling of dimethylamine-borane (Me2NH·BH3) assessed. The FLP system [(C9H7)2ZrO(C6H4)PtBu2][B(C6F5)4] is shown to give unprecedented turnover frequencies (TOF) for a catalyst based on a group 4 metal (TOF ≥ 600 h-1), while also proving to be the most efficient FLP catalyst reported to date. The mechanism of this reaction has been probed using analogous intermolecular Zr(IV)/P FLPs, permitting deconvolution of the reactions taking place at both the Lewis acidic and basic sites. Elucidation of this mechanism revealed an interesting cooperative two-cycle process where one cycle is FLP mediated and the other, a redistribution of a linear diborazane intermediate, relies solely on the presence of a Zr(IV) Lewis acid.
B-Methylated Amine-Boranes: Substituent Redistribution, Catalytic Dehydrogenation, and Facile Metal-Free Hydrogen Transfer Reactions
Stubbs, Naomi E.,Sch?fer, Andr,Robertson, Alasdair P.M.,Leitao, Erin M.,Jurca, Titel,Sparkes, Hazel A.,Woodall, Christopher H.,Haddow, Mairi F.,Manners, Ian
supporting information, p. 10878 - 10889 (2015/11/27)
Although the dehydrogenation chemistry of amine-boranes substituted at nitrogen has attracted considerable attention, much less is known about the reactivity of their B-substituted analogues. When the B-methylated amine-borane adducts, RR'NH·BH2Me (1a: R = R' = H; 1b: R = Me, R' = H; 1c: R = R' = Me; 1d: R = R' = iPr), were heated to 70 °C in solution (THF or toluene), redistribution reactions were observed involving the apparent scrambling of the methyl and hydrogen substituents on boron to afford a mixture of the species RR'NH·BH3-xMex (x = 0-3). These reactions were postulated to arise via amine-borane dissociation followed by the reversible formation of diborane intermediates and adduct reformation. Dehydrocoupling of 1a-1d with Rh(I), Ir(III), and Ni(0) precatalysts in THF at 20 °C resulted in an array of products, including aminoborane RR'N=BHMe, cyclic diborazane [RR'N-BHMe]2, and borazine [RN-BMe]3 based on analysis by in situ 11B NMR spectroscopy, with peak assignments further supported by density functional theory (DFT) calculations. Significantly, very rapid, metal-free hydrogen transfer between 1a and the monomeric aminoborane, iPr2N=BH2, to yield iPr2NH·BH3 (together with dehydrogenation products derived from 1a) was complete within only 10 min at 20 °C in THF, substantially faster than for the N-substituted analogue MeNH2·BH3. DFT calculations revealed that the hydrogen transfer proceeded via a concerted mechanism through a cyclic six-membered transition state analogous to that previously reported for the reaction of the N-dimethyl species Me2NH·BH3 and iPr2N=BH2. However, as a result of the presence of an electron donating methyl substituent on boron rather than on nitrogen, the process was more thermodynamically favorable and the activation energy barrier was reduced.
Rehydrogenation of aminoboranes to amine-boranes using H2O: Reaction scope and mechanism
Leitao, Erin M.,Manners, Ian
supporting information, p. 2199 - 2205 (2015/05/13)
Water has been successfully employed as a reagent with which to rehydrogenate aminoboranes (e.g., iPr2N=BH2, 2,2,6,6-Me4C5H6N=BH2, and also transient Me2N=BH2 derived from 1/2[Me2N-BH2]2) to amine-boranes (e.g., iPr2NH·BH3, 2,2,6,6-Me4C5H6NH·BH3, Me2NH·BH3) in approximately 30 yield. The conversion to amine-boranes from the corresponding aminoboranes using this method represents an example of a metal-free, single-step route for the hydrogenation of the B=N bond. Deuterium labeling studies indicated that the protic hydrogen (N-H) on the rehydrogenated amine-borane was derived from H2O, whereas the third hydridic hydrogen (B-H) on the amine-borane was generated from the formation of a postulated hydride-bridged intermediate H2B(μ-H)(μ-NR2)B(OH)H (R2 = Me2, iPr2, 2,2,6,6-Me4C5H6), which requires a second equivalent of the starting aminoborane, thus explaining the low yield. Formation of insoluble borates (BxOyHz) provides a driving force for the reaction. Significantly, the yield can be increased by adding a sacrificial source of BH3 (e.g., to ca. 53% for BH3·THF) or by adding a separate source of H- (e.g., to ca. 95% for LiBH4) to complement the H+ (from H2O) in a more atom-efficient reaction.
