14401-75-3Relevant articles and documents
Lewis Acidic Boranes, Lewis Bases, and Equilibrium Constants: A Reliable Scaffold for a Quantitative Lewis Acidity/Basicity Scale
Mayer, Robert J.,Hampel, Nathalie,Ofial, Armin R.
supporting information, p. 4070 - 4080 (2021/01/29)
A quantitative Lewis acidity/basicity scale toward boron-centered Lewis acids has been developed based on a set of 90 experimental equilibrium constants for the reactions of triarylboranes with various O-, N-, S-, and P-centered Lewis bases in dichloromethane at 20 °C. Analysis with the linear free energy relationship log KB=LAB+LBB allows equilibrium constants, KB, to be calculated for any type of borane/Lewis base combination through the sum of two descriptors, one for Lewis acidity (LAB) and one for Lewis basicity (LBB). The resulting Lewis acidity/basicity scale is independent of fixed reference acids/bases and valid for various types of trivalent boron-centered Lewis acids. It is demonstrated that the newly developed Lewis acidity/basicity scale is easily extendable through linear relationships with quantum-chemically calculated or common physical–organic descriptors and known thermodynamic data (ΔH (Formula presented.)). Furthermore, this experimental platform can be utilized for the rational development of borane-catalyzed reactions.
Preparation method of terbutaline sulfate
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Paragraph 0058; 0063-0067, (2020/08/09)
The invention relates to the field of preparation of chemicals, in particular to a preparation method of terbutaline sulfate. The invention provides a preparation method of terbutaline sulfate. With simple and low-cost acetophenone as an initial raw material, the terbutaline is prepared through five-step reaction; then the terbutaline is subjected to salifying and purification to obtain terbutaline sulfate. According to the method disclosed by the invention, the total synthesis route of terbutaline is effectively shortened, so that the method is simple in intermediate purification, single in reaction solvent, simple in process, mild in reaction condition, easy to operate, high in total yield and more suitable for industrial production; the burden of workshop waste liquid treatment and purification is relieved, the three wastes and reaction energy consumption are reduced, the whole route is combined, research and control of raw material medicine impurities are better facilitated, and working hours are shortened technically and the three wastes and reaction energy consumption are reduced technically.
Structure-reactivity effects on primary deuterium isotope effects on protonation of ring-substituted α-methoxystyrenes
Tsang, Wing-Yin,Richard, John P.
supporting information; experimental part, p. 13952 - 13962 (2009/12/25)
Primary product isotope effects (PIEs) on L+ and carboxylic acid catalyzed protonation of ring-substituted α-methoxystyrenes (X-1) to form oxocarbenium ions X-2+ in 50/50 (v/v) HOH/DOD were calculated from the yields of the α-CH
A marcus treatment of rate constants for protonation of ring-substituted α-methoxystyrenes: Intrinsic reaction barriers and the shape of the reaction coordinate
Richard, John P.,Williams, Kathleen B.
, p. 6952 - 6961 (2008/02/09)
Rate and equilibrium constants were determined for protonation of ring-substituted α-methoxystyrenes by hydronium ion and by carboxylic acids to form the corresponding ring-substituted α-methyl α-methoxybenzyl carbocations at 25°C and I = 1.0 (KCl). The thermodynamic barrier to carbocation formation increases by 14.5 kcal/mol as the phenyl ring substituent(s) is changed from 4-MeO- to 3,5-di-NO2-, and as the carboxylic acid is changed from dichloroacetic to acetic acid. The Bronsted coefficient a for protonation by carboxylic acids increases from 0.67 to 0.77 over this range of phenyl ring substituents, and the Bronsted coefficient β for proton transfer increases from 0.63 to 0.69 as the carboxylic acid is changed from dichloroacetic to acetic acid. The change in these Bronsted coefficients with changing reaction driving force, ?α/?ΔG°av = ?β/ ?ΔG°av = 1/8Λ = 0.011, is used to calculate a Marcus intrinsic reaction barrier of Λ = 11 kcal/mol which is close to the barrier of 13 kcal/mol for thermoneutral proton transfer between this series of acids and bases. The value of α = 0.66 for thermoneutral proton transfer is greater than α = 0.50 required by a reaction that follows the Marcus equation. This elevated value of β may be due to an asymmetry in the reaction coordinate that arises from the difference in the intrinsic barriers for proton transfer at the oxygen acid reactant and resonance-stabilized carbon acid product.
Contrast media
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, (2008/06/13)
The invention provides low viscosity iodinated aryl compounds, useful as X-ray contrast agents of formula I wherein n is 0 or 1, and where n is 1 each C6R5moiety may be the same or different; X denotes a bond or a group providing a 1
Iodinated x-ray contrast media
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, (2008/06/13)
The invention provides low viscosity iodinated aryl compounds, useful as X-ray contrast agents, of formula C6R6wherein three non-adjacent R groups are iodine and the remaining R groups are non-ionic, hydrophilic moieties, said compou
Tricyclic compounds and drug compositions containing the same
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, (2008/06/13)
Compounds having a β-3 adrenaline receptor agonist and are useful as drugs for the treatment and prevention of diabetes, obesity, hyperlipemia, etc., represented by a general formula (I) and salts thereof, and a process for producing these, and their intermediates, wherein R represents hydrogen or methyl; R1 represents hydrogen, halogen, hydroxy, benzyloxy, amino, or hydroxymethyl; R2 represents hydrogen, hydroxymethyl, NHR3, SO2 NR4 R4', or nitro; R6 represents hydrogen or lower alkyl; and X represents nitrogen, R9 represents hydrogen, one of R7 and R8 represent hydrogen, and the other thereof represents hydrogen, amino, acetylamino, or hydroxy.
Contrast media
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, (2008/06/13)
The invention provides low viscosity iodinated aryl compounds, useful as X-ray contrast agents, of formula I STR1 (wherein n is 0 or 1, and where n is 1 each C6 R5 moeity may be the same or different; each group R is a hydrogen atom,
Contrast media
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, (2008/06/13)
The invention provides low viscosity iodinated aryl compounds, useful as X-ray contrast agents, of formula I STR1 (wherein n is 0 or 1, and where n is 1 each C6 R5 moeity may be the same or different; each group R is a hydrogen atom,
