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: R3N + CH3I → (CH3)R3N+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.
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