Direct conversion of N-ethylamines into functionalised amides by S2Cl2

Hünig's base 1 is known to react extensively with S₂Cl₂ to give monocyclic, bicyclic and fused tricyclic 1,2-dithioles with the N-ethyl group intact, but with S₂Cl₂ and DABCO in chloroform at 0 °C 1 is converted into dichloroacetamide 2 by selective reaction of the N-ethyl group in a new one-pot transformation; ethyl-substituted derivatives of 1, diethylisopropylamine 17 and triethylamine react similarly though the last, less bulky, amine also gives trichloroacetamide 20.