AA 6283 then UA 3376 at O'Hare
Des Moines → Chicago → St Louis
Timetable, Chicago time
15:44AA 6283 from Des Moines at the gate
11:00UA 3376 to St Louis leaves the gate
19 h 16 apart on the timetable, overnight
UA 3376 leaves 19 h 16 after AA 6283 arrives on the timetable: more than half a day, so not a connection we count.