EA-mechanism

With pyridine 7V-oxides the situation is reversed in that amide ion reacts at the 4-position by the AE mechanism but at the 2-position by the EA mechanism, albeit in poor yield (Scheme 137) (67RTC655). 

The Sn(EA) mechanism involves a preliminary base-promoted elimination to yield a heteroaryne intermediate and the subsequent addition of, e.g., NH3 to yield the substitution product(s).85... 

Amination of 4-bromo- and 4-chloro-l,8-naphthyridine (108a and 108b) also affords a mixture of 107 and 109 (ratio of about 30 70 determined by H-NMR spectroscopy of the crude reaction mixture).29 This ratio is somewhat different from that found in the amination of 105b (43 57) and indicates that 108 undergoes an aminodebromination at C-4 [SN(AE) pso], in addition to the SN(EA) reaction involving the intermediacy of 106 It was calculated that 4-bromo-1,8-naphthyridine reacts at about 40% according to this SN(AE) process and 60% according to the S EA) mechanism.29... 

In this reaction 2,4-diNH,-l,5-naphthyridine is obtained the amino group on position 4 is introduced via an S EA) mechanism and the amino group at C-2 via an SN(AE) pso reaction. 

Crofts AR, Guergova-Kuras M, Huang LS, Kuras R, Zhang ZL, Berry EA. Mechanism of ubiquinol oxidation by the bc(l) complex Role of the iron sulfur protein and its mobility. Biochem. 1999 38 15791-15806. 

Echavarren has also studied intramolecular ortho C-H functionalization of aromatics by alkylpalladium(II) species (Scheme 6). In a system where the aromatic ring is deuterated at one of the ortho positions, the production of a statistically equivalent mixture of both deuterated (19) and nondeuterated (20) products was observed. The absence of a kinetic isotope effect supports an EAS mechanism in which deprotonation is not rate limiting [24], The EAS mechanism for C-H activation by an alkylpalladium(II) species is in stark contrast to the mechanism of C-H functionalization reactions by vinyl- or arylpalladium(II) species, where proton abstraction has been determined to be rate limiting [25]... 

Neuwelt EA. Mechanisms of disease the blood-brain barrier. Neurosurgery 2004 54 131-140 discussion 141-132. 

G. M. Swallowe, in G. M. Swallowe, eA,Mechanical Properties and Testing of Polymers, Kluwer Academic Publishers, Dordrecht, 1999, p. 40. 

Santiago El, Batista MS, Assaf EM, TicianeUi EA. Mechanism of CO tolerance on molybdenum-based electrocatalysts for PEMFC. J Electrochem Soc 2004 151 A944-9. 

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