AA 3409 then UA 4606 at O'Hare
St Louis → Chicago → Richmond
Timetable, Chicago time
07:34AA 3409 from St Louis at the gate
07:30UA 4606 to Richmond leaves the gate
23 h 56 apart on the timetable, overnight
UA 4606 leaves 23 h 56 after AA 3409 arrives on the timetable: more than half a day, so not a connection we count.