A
tosyl group (abbreviated Ts or Tos) is CH
3C
6H
4SO
2. This group is usually derived from the compound
tosyl chloride, CH
3C
6H
4SO
2Cl (abbreviated TsCl), which forms esters and amides of
toluenesulfonic or
tosylic acid. The
para orientation illustrated (
p-toluenesulfonyl) is most common, and by convention
tosyl refers to the
p-toluenesulfonyl group.