Collection of Czechoslovak Chemical Communications - digital archive 

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 (C_CO) and C₁ carbon of the aromatic ring (C_Ar). Content of the 2-substituted 4,6-dinitrophenols formed by nucleophilic attack at C_CO 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 C_Ar, whereas both polar and steric effect operate in the attack at C_CO. Methoxide anion attacks the C_CO of 2,4-dinitrophenyl ester even faster than the C_CO of 2,4,6-trinitrophenyl ester.