Effective Synthesis of α,ω-Diaminoalkanes by the Optimized Gabriel Method

Alkylation of phthalimide with α,ω-dibromoalkanes in dimethylformamide in the presence of anhydrous potassium carbonate afforded a series of α,ω-diphthalimidoalkanes. Their subsequent hydrolysis in a potassium hydroxide solution, steam distillation of the diamine bases, and neutralization of the distillate with hydrochloric acid yielded the target α,ω-diaminoalkanes as dihydrochlorides with overall yields of 90–96%.