DL 5680 then DL 1599 at Boston
Pittsburgh → Boston → Washington National
Timetable, Boston time
20:47DL 5680 from Pittsburgh at the gate
20:05DL 1599 to Washington National leaves the gate
23 h 18 apart on the timetable, overnight
DL 1599 leaves 23 h 18 after DL 5680 arrives on the timetable: more than half a day, so not a connection we count.