Begin with a benzene ring bearing two substituents: a methyl group at ring carbon 4 and a sulfonyl group at ring carbon 1, where the sulfur is doubly bonded to two oxygens. Attached to the sulfonyl group is a three-carbon chain (designated as C1'-C2'-C3', moving away from the sulfur). C1' is a methylene (-CH2-), C3' is a methyl (-CH3), and C2' is a methine (-CH-) that carries an additional substituent. This substituent consists of two consecutive carbonyl groups (each carbonyl being double-bonded to oxygen) that are bonded together, with the second carbonyl carbon bearing a methyl group (i.e., the substituent on C2' is -C(=O)-C(=O)-CH3).