4tolyl
4tolyl, commonly written as p-tolyl, is the para-substituted methylphenyl aryl group used in organic chemistry as a substituent connected to the rest of a molecule through the benzene ring. It corresponds to the 4-methylphenyl group, indicating a methyl substituent at the 4-position relative to the point of attachment on the ring. The preferred IUPAC name for this substituent is 4-methylphenyl; tolyl is a traditional, non-systematic designation still widely encountered in the literature.
Structure and relation to toluene: The 4-tolyl group consists of a benzene ring bearing both a methyl
Nomenclature and representations: In systematic nomenclature, the substituent is described as 4-methylphenyl. In common usage, 4-tolyl,
Applications and synthesis: The 4-tolyl moiety appears in a wide range of aryl compounds, including polymers,
See also: o-tolyl and m-tolyl for the other positional isomers of the tolyl group.