UA 745 then B6 1337 at Boston
Chicago O'Hare → Boston → Detroit
Timetable, Boston time
19:14UA 745 from Chicago O'Hare at the gate
18:15B6 1337 to Detroit leaves the gate
23 h 01 apart on the timetable, overnight
B6 1337 leaves 23 h 01 after UA 745 arrives on the timetable: more than half a day, so not a connection we count.