Begin by labeling the aromatic six-membered diazine ring so that the carbon bearing the isopropyl group is position 1. Moving clockwise:
- Position 1 (C) has an isopropyl substituent (-C(CH3)2).
- Position 2 (N) has no substituents.
- Position 3 (C) bears a hydroxyl group.
- Position 4 (C) has no substituents.
- Position 5 (C) is connected through an oxygen atom to a phenyl ring. In this phenyl ring, designate the carbon attached to the oxygen as position 1; this ring carries a bromine substituent at position 3 and a fluorine substituent at position 5 (both meta to the bridging oxygen).
- Position 6 (N) completes the ring.
