UA 1232 then DL 5818 at Boston
Denver → Boston → Raleigh-Durham
Timetable, Boston time
15:32UA 1232 from Denver at the gate
09:55DL 5818 to Raleigh-Durham leaves the gate
18 h 23 apart on the timetable, overnight
DL 5818 leaves 18 h 23 after UA 1232 arrives on the timetable: more than half a day, so not a connection we count.