linear free energy ortho-correlations
The kinetics of SNAr reactions of some 2-bromo-3-X-5-nitrothiophenes (X = Me, H, Br, CONH2, CO2Me, COMe, SO2Me, CN and NO2) with some primary (n-butylamine and benzylamine) and secondary (pyrrolidine, piperidine, morpholine and N-benzylamine) amines have been measured in benzene as a function of nucleophile concentration. Most of the reactions studied show apparent kinetic constants little affected or not affected by an increase in amine concentration, indicating that the overall reaction rate is controlled by the formation of the reaction intermediate. The reactions of the substrates where X = Br and CN with the two primary amines proved to be base-catalysed. The k3B/k-1values calculated for these substituents are inconsistent with the hypothesis of a base catalysis for the intermediate decomposition and strongly suggest a catalysis of the first step of the reaction pathway.
Linear free energy ortho-correlations in the reactions of some 2-bromo-5-nitro-3-x-thiophenes with primary and secondary amines in benzene / Consiglio G.; Frenna V.; Guernelli S.; Macaluso G.; Spinelli D.. - In: JOURNAL OF THE CHEMICAL SOCIETY. PERKIN TRANSACTIONS 2. - ISSN 1472-779X. - STAMPA. - 5:(2002), pp. 971-975. [10.1039/B111544H]
Linear free energy ortho-correlations in the reactions of some 2-bromo-5-nitro-3-x-thiophenes with primary and secondary amines in benzene
Consiglio G.
;Guernelli S.;
2002
Abstract
The kinetics of SNAr reactions of some 2-bromo-3-X-5-nitrothiophenes (X = Me, H, Br, CONH2, CO2Me, COMe, SO2Me, CN and NO2) with some primary (n-butylamine and benzylamine) and secondary (pyrrolidine, piperidine, morpholine and N-benzylamine) amines have been measured in benzene as a function of nucleophile concentration. Most of the reactions studied show apparent kinetic constants little affected or not affected by an increase in amine concentration, indicating that the overall reaction rate is controlled by the formation of the reaction intermediate. The reactions of the substrates where X = Br and CN with the two primary amines proved to be base-catalysed. The k3B/k-1values calculated for these substituents are inconsistent with the hypothesis of a base catalysis for the intermediate decomposition and strongly suggest a catalysis of the first step of the reaction pathway.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
