Complex sentence: Propylhexedrine is a structural analog of methamphetamine, the only difference is that propylhexedrine has a saturated cyclohexane ring where methamphetamine has a benzene ring.
Split into simpler sentences: Propylhexedrine is a structural analog of methamphetamine. The only difference is that propylhexedrine has a saturated cyclohexane ring where methamphetamine has a benzene ring.