title: Methiodide
text: # Methiodide
  
  In organic chemistry, a methiodide is a chemical derivative produced by the reaction of a compound with methyl iodide. Methiodides are often formed through the methylation of tertiary amines:
  
      $R_3N$ + $CH_3I$ → $(CH_3)R_3N^+I^−$
  
  Whereas the parent amines are hydrophobic and often oily, methiodides, being salts, are somewhat hydrophilic and exhibit high melting points. Methiodides exhibit altered pharmacological properties as well.
  
  Examples include:
  
  * Cocaine methiodide, a charged cocaine analog which cannot pass the blood brain barrier and enter the brain
  * Bicuculline methiodide, a water-soluble form of bicuculline
  
  Tertiary phosphines and phosphite esters also form methiodides.
  
  