UA 787 then UA 3376 at O'Hare
Houston → Chicago → St Louis
Timetable, Chicago time
16:29UA 787 from Houston at the gate
11:00UA 3376 to St Louis leaves the gate
18 h 31 apart on the timetable, overnight
UA 3376 leaves 18 h 31 after UA 787 arrives on the timetable: more than half a day, so not a connection we count.