Inorganic chemistry, amethoxy group is thefunctional group consisting of amethyl group bound tooxygen. Thisalkoxy group has the formulaR−O−CH3.
On abenzene ring, theHammett equation classifies a methoxy substituent at thepara position as anelectron-donating group, but as anelectron-withdrawing group if at themeta position. At theortho position,steric effects are likely to cause a significant alteration in the Hammett equation prediction, which otherwise follows the same trend as that of thepara position.
The simplest of methoxy compounds aremethanol anddimethyl ether. Other methoxy ethers includeanisole andvanillin. Many metal alkoxides contain methoxy groups, such astetramethyl orthosilicate andtitanium methoxide.Esters with a methoxy group can be referred to as methyl esters, and the —COOCH3 substituent is called a methoxycarbonyl.[1]
In nature, methoxy groups are found on nucleosides subjected to2′-O-methylation, for example, in variations of the5′-cap structure known as cap-1 and cap-2. They are also common substituents inO-methylated flavonoids, whose formation is catalyzed byO-methyltransferases that act onphenols, such ascatechol-O-methyl transferase (COMT). Many natural products in plants, such aslignins, are generated via catalysis bycaffeoyl-CoAO-methyltransferase.[2]
Organic methoxides are often produced bymethylation of alkoxides.[3][4] Some aryl methoxides can be synthesized by metal-catalyzed methylation ofphenols, or by methoxylation ofaryl halides.[5][6]
