Study of reaction of substituted nitrophenyl acetates and benzoates with nucleophiles

Abstract

Reaction of 2-substituted 4,6-dinitrophenyl acetates and benzoates with methoxide, 4-bromophenoxide and acetate anions and with anion of methyl cyanoacetate has been studied in methanol at 25 °C, and the respective rate constants have been determined along with the rate constant ratios of nucleophilic attacks at carbonyl carbon (CCO) and C1 carbon of the aromatic ring (CAr). Content of the 2-substituted 4,6-dinitrophenols formed by nucleophilic attack at CCO increases in the product with increasing hardness of the nucleophiles in the series methyl cyanoacetate anion < 4-bromophenoxide anion < methoxide anion. The substituents polar effects are decisive for the attack at CAr, whereas both polar and steric effect operate in the attack at CCO. Methoxide anion attacks the CCO of 2,4-dinitrophenyl ester even faster than the CCO of 2,4,6-trinitrophenyl ester.