AA 2146 then UA 8130 at O'Hare
Boston → Chicago → Sioux Falls
Timetable, Chicago time
08:00AA 2146 from Boston at the gate
20:30UA 8130 to Sioux Falls leaves the gate
12 h 30 apart on the timetable
UA 8130 leaves 12 h 30 after AA 2146 arrives on the timetable: more than half a day, so not a connection we count.