542-11-0Relevant articles and documents
Straightforward synthesis of amino-3-hydroxypyridin-4-one iron chelators via BBr3-mediated tandem reduction of azides and deprotection of methyl ether
Gan, Bing,Jiang, Xiaoying,Mi, Zhisheng,Zhang, Changjung,Bai, Renren,Shuai, Qi,Xie, Yuanyuan
supporting information, p. 73 - 79 (2019/01/19)
A novel and straightforward BBr3-mediated tandem reduction of organic azide and demethylation of methyl ether were described. This method provides a new approach to prepare a series of new amino-3-hydroxypyridin-4-one iron chelators, which can be used in the treatment of iron also applicable to other substrates like benzyl azides and aryl azides.
Selective catalytic Hofmann: N -alkylation of poor nucleophilic amines and amides with catalytic amounts of alkyl halides
Xu, Qing,Xie, Huamei,Zhang, Er-Lei,Ma, Xiantao,Chen, Jianhui,Yu, Xiao-Chun,Li, Huan
supporting information, p. 3940 - 3944 (2016/07/21)
Using only catalytic amounts of alkyl halides in the reactions of poor nucleophilic amines/amides and alcohols led to a selective Hofmann N-alkylation reaction catalytic in alkyl halides, providing a practical and efficient method for the practical synthesis of mono- or di-alkylated amines/amides in high selectivities. This new method avoids the use of large amounts of bases, alkyl halides, and solvents, and generates water as the only byproduct. Preliminary mechanistic studies showed that alkyl halides are key intermediates/catalysts regeneratable in the reaction cycle.
Aromatic Nucleophilic Substitution Reactions of Some 2-L-3-Nitro-5-X-thiophenes with Piperidine and Aniline in Methanol. Substituent Constants for the Thiophene System
Consiglio, Giovanni,Frenna, Vincenzo,Arnone, Caterina,Mezzina, Elisabetta,Spinelli, Domenico
, p. 2187 - 2190 (2007/10/02)
The rate constants for the reactions of some 2-L-3-nitro-5-X-thiophenes 1-4 with aniline and of compounds (4) with piperidine in methanol have been measured at various temperatures.By using the data obtained in this work as well as previously available data sets, a series of optimized 'thiophene' ?τ values has been calculated.The susceptibility constants ρ(L) of the various sets have been analysed in the framework of the reactivity-selectivity principle.
Stabilities of complexes of Br- with substituted benzenes (SB) based on determinations of the gas-phase equilibria Br- + SB = (BrSB)-
Paul, Gary J. C.,Kebarle, Paul
, p. 1148 - 1154 (2007/10/02)
Equilibria involving some forty substituted benzenes (SB) and the bromide ion (SB + Br- = SBBr-) in the gas phase were determined with a pulsed electron, high-pressure mass spectrometer (PHPMS). The resulting -ΔG°1 provide information on the stabilities of the SBBr- complexes. Previous work, involving gas-phase thermochemical data for. X- (CH3O-, F-, C1-, Br-, I-) and quantum chemical calculations, indicate that the most stable SB·X- complexes might have a variety of structures, depending on X- and the nature of the substituents. Thus X- may engage in hydrogen bonding to an aromatic hydrogen atom, or lead to a σ-bonded (Meisenheimer) complex, or form a complex where X- is on an axis perpendicular to the benzene plane. A Taft substituent analysis of the δΔG°1 indicates that Br- and Cl- form aromatic C-H hydrogen-bonded complexes with all singly substituted benzenes. The field effects of the substituents provide the dominant contribution to the bonding in these complexes. Similar conclusions are reached also for the singly substituted nitrobenzenes and Br-. A clearcut analysis of the bonding to Br- when triply substituted benzenes with strongly electron withdrawing substituents like CF3, CN, and NO2 are present could not be obtained. In these cases all three bonding structures mentioned above may have similar stabilities.
BIFUNCTIONAL MECHANISM OF CATALYSIS IN REACTIONS LEADING TO FORMATION OF α-AMINO KETONES
Popov, A. F.,Anikeev, A. V.
, p. 945 - 948 (2007/10/02)
The kinetics of the reaction of α-bromoacetophenone and benzyl bromide with aniline and pyridine in the presence of additions of acetic acid and phenol in benzene at 30 deg C were investigated.The catalytic effect due to the activity of the uncombined forms of the catalyst, their dimers, and their 1:1 complexes with the amines were separated quantitatively.The change in the catalytic activity of the respective particles in the solutions with variation in the structure of the reagents is examined, and possible mechanisms for the catalytic reactions are discussed on this basis.It is concluded that there is a bifunctional mechanism of catalysis by acetic acid in the reaction of α-bromoacetophenone with aniline.
EFFECT OF THE NATURE OF THE LEAVING GROUP IN REACTIONS OF 2-X-N-ETHYLPYRIDINIUM SALTS WITH AMINES IN ACETONITRILE
Titskii, G. D.,Mitchenko, E. S.
, p. 1949 - 1954 (2007/10/02)
The rate-determining stage in the nucleophilic substitution reactions of 2-X-N-ethylpyridinium salts with piperidine in acetonitrile changes, depending on the nature of the leaving group X.In the case where X = Hlg the controlling stage is the formation of the C-N bond.When X = 4-NO2C6H4O3, 3,4-(NO2)2C6H3O, and 2,6-(NO2)2C6H3O, nucleophilic substitution at the carbon atom is controlled by cleavage of the C-X bond.Nucleophilic substitution at a carbon atom of the benzene ring predominates in the reaction of 2-(2,4-dinitrophenoxy)-N-ethylpyridinium salt with piperidine.
NICKEL-CATALYZED AMIDATION OF BROMO- AND IODOBENZENE
Giannoccaro, Potenzo,Pannacciulli, Emiliano
, p. 119 - 128 (2007/10/02)
The carbonylation of aryl halides in the presence of p-RC6H4NH2 (R = H, CH3, Cl) or C6H5NHR (R = CH3, C2H5) and a catalytic amount of a nickel(II) or nickel(0) tertiary phosphine complex at 150 degC or above under carbon monoxide pressures is reported.Amides were obtained in high yields in reactions with p-RC6H4NH2, but with C6H5NHR compounds the expected N-alkyl benzanilides were not formed, benzanilide in low yield being formed instead.A possible catalytic cycle based on an active Ni(0)-carbonyl complex is suggested, and the observed deactivation of the catalytic system when the carbon monoxide pressure falls to 6 atm or below, is accounted for in terms of a side reaction which produces an inactive Ni(II) compound.
TRANSITION THROUGH AN ISOPARAMETRIC POINT RELATIVE TO SUBSTITUENT IN THE REACTION OF AROYL BROMIDES WITH PRIMARY ARYLAMINES. RELATIONSHIP BETWEEN REACTIVITY AND SELECTIVITY
Shpan'ko, I. V.,Goncharev, A. N.,Chetverova, E. V.,Likhomanenko, E. E.
, p. 1290 - 1295 (2007/10/02)
Rates were measured for the reactions of aroyl bromides with primary arylamines in 1:1 chlorobenzene-cyclohexane at 25 deg C.The kinetic data were treated by the Hammett-Taft equations and cross correlation.This is the first reported transition through an isoparametric point relative to the structure of the nucleophile accompanied by inversion of the sign of the sensitivity parameter relative to the substrate structure in the aroyl bromide-primary arylamine reaction system.The results of the cross correlation analysis were interpreted on the basis of a concerted mechanism involving nucleophilic substitution at the carbonyl carbon atom.The relationship between the reactivity of the system studied and its selectivity was examined.
KINETICS OF THE REACTIONS OF A 2-BROMO-N-ETHYLPYRIDINIUM SALT WITH PRIMARY AROMATIC AMINES IN ACETONITRILE
Litvinenko, L. M.,Titskii, G. D.,Mitchenko, E. S.
, p. 1553 - 1556 (2007/10/02)
The kinetics of the reactions of 2-bromo-N-ethylpyridinium bromide with ringsubstituted aromatic amines in acetonitrile at 25 deg C were investigated.The effect of the substituents in the benzene ring of the aromatic amines on the kinetics of nucleophilic substitution with the halogenopyridinium salt is described by a correlation equation with the ?0 constants.The reactivity of aliphatic and aromatic amines in reactions with 2-bromo-N-ethylpyridinium bromide in acetonitrile is described by a single correlation equation, which defines the joint contribution from electronic and steric factors of the substituets in the nucleophilic reagent.
Kinetics of Reactions of ω-Bromo-2-acetonaphthone with Pyridine and Substituted Anilines in Various Solvents
Ananthakrishnanadar, P.,Varghesedharumaraj, G.,Subramanian, S. V.
, p. 953 - 956 (2007/10/02)
Rate constants for the reactions of ω-bromo-2-acetonaphthone with aniline and pyridine in various protic and aprotic solvents have been determined at three temperatures.The rates of reaction with pyridine in simple alcohols are less than those with aniline.Values of Hammet ρ-constant have been obtained for the reactions with substituted anilines in a few solvents.Multiple correlation of log k40 deg C for the reaction with aniline in various alcohols employing several solvent parameters is highly successful.
