Ptolyl

Ptolyl, also written p-tolyl or 4-methylphenyl, refers to the para-tolyl substituent, an aryl group derived from toluene by removing a hydrogen to enable attachment to another molecule. It is one of three tolyl isomers, the others being o-tolyl and m-tolyl. The p-tolyl group consists of a benzene ring bearing a methyl substituent at the para position relative to the point of attachment to the rest of the molecule. The p-tolyl radical has the formula C7H7−; in IUPAC terms it is 4-methylphenyl.

Applications and properties: The methyl substituent is mildly electron-donating, which can influence the electronic properties of compounds bearing the p-tolyl group and affect reaction outcomes in cross-coupling chemistry, electrophilic aromatic substitution, and related transformations. The group is nonpolar and relatively hydrophobic.

Preparation and use: p-Tolyl groups are widely used in organic synthesis as aryl moieties. They appear in reagents such as p-tolyl halides (for example p-tolyl chloride, p-tolyl bromide), p-tolylboronic acids, and p-tolyl Grignard reagents. They serve as arylating partners in Suzuki, Heck, and related cross-coupling reactions and are present in dyes, ligands, and pharmaceutical intermediates. Common routes to access p-tolyl derivatives include cross-coupling of 4-bromotoluene or 4-chlorotoluene with aryl or alkyl partners.

See also: o-tolyl, m-tolyl; 4-methylphenyl.