UA 587 then UA 3752 at Dulles
Chicago O'Hare → Washington → Oklahoma City
Timetable, Washington time
17:24UA 587 from Chicago O'Hare at the gate
09:40UA 3752 to Oklahoma City leaves the gate
16 h 16 apart on the timetable, overnight
UA 3752 leaves 16 h 16 after UA 587 arrives on the timetable: more than half a day, so not a connection we count.