Methiodide Explained

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^[1]
• Bicuculline methiodide, a water-soluble form of bicuculline

Tertiary phosphines and phosphite esters also form methiodides.^[2]

Notes and References

1. Potencies of Cocaine Methiodide on Major Cocaine Targets in Mice . Hill ER, Tian J, Tilley MR, Zhu MX, Gu HH . PLOS ONE . 2009 . 4 . 19855831 . 10 . 2762027 . e7578 . 10.1371/journal.pone.0007578 . Manzoni . Olivier Jacques. 2009PLoSO...4.7578H . free .
2. H. N. Rydon. 10.15227/orgsyn.051.0044. Alkyl Iodides: Neopentyl Iodide and Iodocyclohexane. Organic Syntheses. 1971. 51. 44.