Reductive cleavage of the nitrogen–nitrogen bond in hydrazine derivatives

Abstract

The reductions of the 1,2-disubstituted hydrazines (4)–(7) having the activating groups toluene-p-sulphonyl, acetyl, ethoxycarbonyl, and trifluoroacetyl respectively have been studied with zinc in acetic acid, aluminium amalgam, sodium in liquid ammonia, sodium in ethanol, and Raney nickel. Satisfactory conditions have been defined for the reductive cleavage of each of these substituted hydrazines (4)–(7). The Diels–Alder adduct (12) of cyclopentadiene and diethyl azodicarboxylate has been oxidised, by m-chloroperoxybenzoic acid to give the epoxide (20), by osmium tetraoxide to give the diol (21), and via hydroboration to give the alcohol (22). Using sodium in liquid ammonia these hydrazine derivatives (20)–(22) and others have been reduced by cleavage of the nitrogen–nitrogen bond to give derivatives of oxygenated cyclic diamines.