UA 2384 then AA 3484 at O'Hare
Miami → Chicago → St Louis
Timetable, Chicago time
11:25UA 2384 from Miami at the gate
09:30AA 3484 to St Louis leaves the gate
22 h 05 apart on the timetable, overnight
AA 3484 leaves 22 h 05 after UA 2384 arrives on the timetable: more than half a day, so not a connection we count.