1. The central sulfur is double-bonded to two oxygens (forming a sulfonyl group) and connects, on one side, to an unsubstituted piperidine ring via its nitrogen and, on the other side, to a phenyl ring ("Ring A").
2. In Ring A, a six-membered phenyl group, the carbon bonded to sulfur is designated as C1. At the C2 position, a substituent featuring a -C(OH)=N- linkage is present. The nitrogen in this linkage is bonded to a second phenyl ring (Ring B).
3. Ring B, also a phenyl group, carries an additional -C(OH)=N- substituent at the meta position relative to its initial attachment point.
4. The nitrogen of this second "C(OH)=N-" group is attached to a -CH2-C(=O)-OCH3 chain (i.e., a methyl ester on a one-carbon spacer from the imino nitrogen).