Debenzylation or Demethylation in Methyl Ester of O‐Alkyl Nitrophenols with Stannous Chloride Dihydrate

Abstract

AbstractStannous chloride dihydrate (SnCl2.2H2O) is an inexpensive and commonly used reagent for nitro group reduction. We observed partial O‐demethylation or O‐debenzylation of O‐alkylated nitrobenzene derivatives when subjected to the nitro reduction with the reagent in ethyl acetate at heating, a generally employed reaction condition. A neat reaction at 80 °C afforded the debenzylated product. Reactions at room temperature yielded corresponding O‐alkylated anilines only. The results show the effect of electron‐withdrawing groups on dealkylation; when at the ortho or para position to the alkoxy group, they enhanced the possibility of dealkylation, and no dealkylation was observed in meta‐oriented substrates. The systematic study may help researchers to choose the proper conditions to prevent undesired products.