Long - lasting expression of Jun and Krox transcription factors and nitric oxide synthase in intrins

1,4-Diaminobutanes of the formula in which R1 is H or -CH3 and R2 and R3 independently of one another are each a radical of the formula in which A is alkyl having 1 to 3 C atoms, -OCH3, -N(CH3)2, -Cl or -Br and R2 also is alkyl having 1 to 3 C atoms, are prepared according to the invention by catalytically hydrogenating succinic acid dinitrile of the formula in the presence of acetic anhydride and hydrolyzing the N,N'-diacetyl-1,4-diaminobutanes thus obtained to diamines of the formula I, which are valuable curing agents for epoxide resins.