Editing Methyl group (section)

==Reactivity==
The reactivity of a methyl group depends on the adjacent [[substituent]]s. Methyl groups can be quite unreactive. For example, in organic compounds, the methyl group resists attack by even the strongest [[acid]]s.{{citation needed|date=April 2024}}

===Oxidation===
The [[oxidation]] of a methyl group occurs widely in nature and industry. The oxidation products derived from methyl are [[hydroxymethyl group]] {{chem2|\sCH2OH}}, [[formyl group]] {{chem2|\sCHO}}, and [[carboxyl group]] {{chem2|\sCOOH}}. For example, [[permanganate]] often converts a methyl group to a carboxyl ({{chem2|\sCOOH}}) group, e.g. the conversion of [[toluene]] to [[benzoic acid]]. Ultimately oxidation of methyl groups gives [[proton]]s and [[carbon dioxide]], as seen in combustion.

===Methylation===
{{main|Methylation}}
Demethylation (the transfer of the methyl group to another compound) is a common process, and [[reagent]]s that undergo this reaction are called methylating agents. Common methylating agents are [[dimethyl sulfate]], [[methyl iodide]], and [[methyl triflate]]. [[Methanogenesis]], the source of natural gas, arises via a demethylation reaction.<ref>Thauer, R. K., "Biochemistry of Methanogenesis: a Tribute to Marjory Stephenson", Microbiology, 1998, volume 144, pages 2377–2406.</ref> Together with ubiquitin and phosphorylation, methylation is a major biochemical process for modifying protein function.<ref>{{cite journal|doi=10.1074/jbc.AW118.003235|pmid=29743234|pmc=6036201|title=The ribosome: A hot spot for the identification of new types of protein methyltransferases|journal=Journal of Biological Chemistry|volume=293|issue=27|pages=10438–10446|year=2018|last1=Clarke|first1=Steven G.|doi-access=free}}</ref>  The field of [[epigenetic]]s focuses on the influence of methylation on gene expression.<ref>{{Cite journal |last=Bird |first=Adrian |date=2002-01-01 |title=DNA methylation patterns and epigenetic memory |url=http://genesdev.cshlp.org/lookup/doi/10.1101/gad.947102 |journal=Genes & Development |language=en |volume=16 |issue=1 |pages=6–21 |doi=10.1101/gad.947102 |issn=0890-9369 |doi-access=free}}</ref>

===Deprotonation===
Certain methyl groups can be deprotonated. For example, the acidity of the methyl groups in [[acetone]] ({{chem2|(CH3)2CO}}) is about 10<sup>20</sup> times more acidic than methane. The resulting [[carbanion]]s are key intermediates in many reactions in [[organic synthesis]] and [[biosynthesis]]. [[Fatty acid]]s are produced in this way.

===Free radical reactions===
When placed in [[benzylic]] or [[allylic]] positions, the strength of the {{chem2|C\sH}} bond is decreased, and the reactivity of the methyl group increases. One manifestation of this enhanced reactivity is the [[Photochemistry|photochemical]] [[Halogenation|chlorination]] of the methyl group in [[toluene]] to give [[benzyl chloride]].<ref name="Ullmann">M. Rossberg et al. "Chlorinated Hydrocarbons" in Ullmann's Encyclopedia of Industrial Chemistry 2006, Wiley-VCH, Weinheim.{{doi|10.1002/14356007.a06_233.pub2}}</ref>