Naming of substituted amines and amides
Substituents are listed alphabetically by the name of the substituent. The N in front of the substituent is a locant, and thus is not used when alphabetizing:


  3-chloro-N-ethyl-4-methyl-N-propylhexanamide is correct because the substituents are in correct alphabetic order: 


chloro, ethyl, methyl, propyl