DL 2570 then AA 3484 at O'Hare
Boston → Chicago → St Louis
Timetable, Chicago time
09:55DL 2570 from Boston at the gate
09:30AA 3484 to St Louis leaves the gate
23 h 35 apart on the timetable, overnight
AA 3484 leaves 23 h 35 after DL 2570 arrives on the timetable: more than half a day, so not a connection we count.