Decarboxylation

In biochemistry

Common biosynthetic decarboxylations of amines are:

• tryptamine
• phenylethylamine
• tyramine
• histamine
• ethanolamine
• GABA
• cadaverine
• arginine to agmatine
• putrescine
• serotonin
• dopamine

Other decarboxylation reactions from the citric acid cycle include:

• pyruvate to acetyl-CoA
• oxalosuccinate to α-ketoglutarate
• α-succinyl-CoA.

Enzymes that catalyze decarboxylations are called decarboxylases or, more formally, carboxy-lyases (EC number 4.1.1).

In organic chemistry

In homologation reactions, in that the chain length becomes one carbon shorter.

Chemical decarboxylations reactions often require extensive heating in high-boiling solvents. hydrochloric acid also affords decarboxylation.^[2] The addition of catalytic amounts of cyclohexen-2-one has been reported to catalyze the decarboxylation of amino acids.^{[citation needed]}

Decarboxylations are especially easy for beta-keto acids due to the formation of a cyclic Hunsdiecker reaction are radical reactions.

Kolbe electrolysis — the electrolysis of salts of carboxylic acids give the decarboxylated dimer products:

CH₃COOH → CH₃COO⁻ → CH₃COO· → CH₃· + CO₂

2CH₃· → CH₃CH₃

This reaction occurs via a radical mechanism as well.^[3]

See also

• Oxidative decarboxylation

References

1. ^ Jim Clark (2004). The Decarboxylation of Carboxylic Acids and their Salts. Chemguide. Retrieved on 2007-10-22.
2. ^ Malonic Ester Synthesis. Organic Chemistry Portal. Retrieved on 2007-10-26.
3. ^ Kolbe Electrolysis. Organic Chemistry Portal. Retrieved on 2007-10-22.