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electronic effects on the reaction site (NH2 group) and the establishment of direct acid-base interactions between substituents X and the catalyst must be considered to explain the observed scheme of rate constants. Weakly acid groups (CH2OH, CONH2 up to OH: pKa of 16-17 up to 10) may help the adsorption over the NaY surface, and so favor the reaction. Aminobenzoic acids (pKa of 4-5), however, are the least reactive substrates, presumably because carboxylic groups go through strong acid-base interactions with the catalyst.
These results represent the first ever reported evidence of strict cooperation between the steric requisites of the faujasite catalyst and the reactivity of an asymmetrical carbonate, in simultaneously inducing high methyl chemoselectivity and mono-N-methylselectivity for primary amines.
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