title: Dimethylaminophosphorus dichloride
text: # Dimethylaminophosphorus dichloride
  
  Dimethylaminophosphorus dichloride is an organophosphorus compound with the formula $Me_2NPCl_2$ (Me = methyl). A colorless liquid, it is a reagent in the preparation of other organophosphorus compounds. Many analogous compounds can be prepared from the reactions of secondary amines and phosphorus trichloride:
  
      2 $R_2NH$ + $PCl_3$ → $R_2NPCl_2$ + $R_2NH_2Cl$
  
  ## Reactions
  
  Further equivalents of amine react with dialkylaminophosphorus dichlorides:
  
      2 $R_2NH$ + $R_2NPCl_2$ → $(R_2N)_2PCl$ + $R_2NH_2Cl$
  
  Since the $P-NR_2$ bond is not attacked by Grignard reagents, dimethylaminophosphorus dichloride can be selectively dimethylated:
  
      2 MeMgBr + $Me_2NPCl_2$ → $Me_2NPMe_2$ + 2 MgBrCl
  
  The resulting dimethylphosphino derivative, a structural relative of tetramethylhydrazine, reacts with hydrogen chloride to give chlorodimethylphosphine:
  
      $Me_2NPMe_2$ + 2 HCl → $ClPMe_2$ + $Me_2NH_2Cl$
  