The synthesis of quaternary five membered N-n-alkyl-hetero-cycles, especially of 4-hydroxy-N(1)-n-alkyl-imidazolium, 2,5-substituted N(3)-n-alkyl-thiazolium and substituted N(2) pyrazolium salts are described. The N-surfactants obtained have a very small critical micelle concentration (CMC) of 10.sup.-5 -10.sup.-7 Mol/Liter, and are capable of forming micelles of different sizes and forms depending on the nature of the anions. The N-detergents can be used as pharmaceuticals.