930-36-9Relevant articles and documents
Protodeboronation of (Hetero)Arylboronic Esters: Direct versus Prehydrolytic Pathways and Self-/Auto-Catalysis
Assante, Michele,Geogheghan, Katherine J.,Hayes, Hannah L. D.,Jin, Na,Leach, Andrew G.,Lloyd-Jones, Guy C.,Noonan, Gary,Tomasi, Simone,Wei, Ran
supporting information, p. 14814 - 14826 (2021/09/13)
The kinetics and mechanism of the base-catalyzed hydrolysis (ArB(OR)2→ ArB(OH)2) and protodeboronation (ArB(OR)2→ ArH) of a series of boronic esters, encompassing eight different polyols and 10 polyfluoroaryl and heteroaryl moieties, have been investigated by in situ and stopped-flow NMR spectroscopy (19F,1H, and11B), pH-rate dependence, isotope entrainment,2H KIEs, and KS-DFT computations. The study reveals the phenomenological stability of boronic esters under basic aqueous-organic conditions to be highly nuanced. In contrast to common assumption, esterification does not necessarily impart greater stability compared to the corresponding boronic acid. Moreover, hydrolysis of the ester to the boronic acid can be a dominant component of the overall protodeboronation process, augmented by self-, auto-, and oxidative (phenolic) catalysis when the pH is close to the pKaof the boronic acid/ester.
Alkylation method for nitrogen-hydrogen containing compounds and application thereof
-
Paragraph 0059; 0060, (2018/10/04)
The invention discloses an alkylation method for nitrogen-hydrogen containing compounds and an application thereof, belonging to the technical field of synthesis of organic compounds. The invention provides a series of methods for a nitrogen alkylation reaction of N-H containing heterocyclic compounds (II) with N,N-dimethylformamide dialkyl acetal as an alkyl source under the condition of no participation of metals, and a product with a hydrogen atom on a nitrogen atom substituted by R1 is obtained. The method provided by the invention has the advantages of highly-efficient reaction, high yield, simple treatment after the reaction, simple and convenient operation, mild reaction conditions, no participation of the metals, high tolerance of functional groups of a reaction substrate, wide range and easy preparation of the substrate, high reaction efficiency after amplification of the reaction, and applicability to large-scale industrial production.
Pyrazolium- versus imidazolium-based ionic liquids: Structure, dynamics and physicochemical properties
Chiappe, Cinzia,Sanzone, Angelo,Mendola, Daniele,Castiglione, Franca,Famulari, Antonino,Raos, Guido,Mele, Andrea
, p. 668 - 676 (2013/03/14)
Ionic liquids (ILs) composed of two different pyrazolium cations with dicyanamide and bis(trifluoromethanesulfonyl)imide anions have been synthesized and characterized by NMR, Kamlet-Taft solvatochromic parameters, conductivity and rheological measurements, as well as ab initio calculations. Density functional calculations for the two pyrazolium cations, 1-butyl-2- methylpyrazolium [bmpz] and 1-butyl-2,3,5-trimethylpyrazolium [bm 3pz], provide a full picture of their conformational states. Homo- and heteronuclear NOE show aggregation motives sensitive to steric hindrance and the anions' nature. Self-diffusion coefficients D for the anion and the cation have been measured by pulsed field gradient spin-echo NMR (PGSE-NMR). The ionic diffusivity is influenced by their chemical structure and steric hindrance, giving the order Dcation > Danion for all of the examined compounds. The measured ion diffusion coefficients, viscosities, and ionic conductivity follow the Vogel-Fulcher-Tammann (VFT) equation for the temperature dependencies, and the best-fit parameters have been determined. Solvatochromic parameters indicate an increased ion association upon going from bis(trifluoromethanesulfonyl)imide to dicyanamide-based pyrazolium salts, as well as specific hydrogen bond donor capability of H atoms on the pyrazolium ring. All of these physical properties are compared to those of an analogous series of imidazolium-based ILs.