Reductive cleavage of azo compounds catalyzed by commercial zinc dust using ammonium formate or formic acid

Azo compounds, both symmetric and unsymmetric, are cleaved to amine(s) by using commercial zinc dust and ammonium formate of formic acid in methanol, tetrahydrofuran or dioxane at room temperature. The reductive cleavage occurs without hydrogenolysis or hydrogenation of reducible moieties, such as -OH, -CH3, -OCH3, -COOH, - COCH3, halogen, etc. The cleavage is very fast, clean, cost effective and high-yielding if compared with earlier methods, such as those using cyclohexene/5% Pd on asbestos, cyclohexane/10% Pd-C or hydrazine/10% Pd C or Raney nickel. (C) 2002 Elsevier Science Ltd. All rights reserved.