CH3ryhmä

CH3ryhmä, commonly known as the methyl group, is a chemical substituent with the formula -CH3. It consists of a single carbon atom bonded to three hydrogen atoms. The carbon is sp3-hybridized, adopting a tetrahedral geometry. The methyl group is a fundamental unit in organic chemistry and a common constituent of alkyl groups.

Occurrence and role: The methyl group is one of the simplest and most widespread substituents in organic molecules. It arises from methane by removing one hydrogen. Methyl groups appear in a wide range of compounds, including methanol derivatives, methyl esters, and many biologically important molecules. In biology, DNA methylation at cytosine residues (5-methylcytosine) is an epigenetic mark that influences gene expression and development; methyl groups also participate in metabolism and signaling pathways.

Properties and reactivity: The methyl group is nonpolar and hydrophobic, contributing to the overall properties of the molecules to which it is attached. It is relatively chemically inert under normal conditions, but benzylic and allylic methyl substituents can undergo oxidation or substitution reactions. In synthesis, methyl groups are introduced by methylation reactions using reagents such as methyl iodide or diazomethane, and can be removed by appropriate deprotection strategies.

Nomenclature and notation: The substituent is commonly abbreviated as Me in shorthand notation. Systematic naming uses the prefix methyl- to indicate one-carbon substituent on a parent hydrocarbon. In common line notations, a CH3 group is represented by a single carbon with three implicit hydrogens.

See also: Alkyl group; Methane; Epigenetics; Methylation.

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