The rate constants for the decomposition of the 2,2-dimethoxy-3-(methylsulfonyl)-5-nitrothiophene Meisenheimer adduct-σ 2 derided from thiophene 1 have been determined in methanol at 20°C. As we will see, the reaction occurs in two distinct stages. In the first, instantaneous formation of an intermediate species 2,H+ (nitronic acid), favoured at low pH. In the second slower stage the adduct-σ 2 is gradually converted into expected thiophene 1.
A. Echaieb, T. Boubaker
Kinetic, adduct-σ, thiophene, nitronic acid