UA 1665 then DL 5845 at Boston
San Francisco → Boston → Philadelphia
Timetable, Boston time
07:56UA 1665 from San Francisco at the gate
06:40DL 5845 to Philadelphia leaves the gate
22 h 44 apart on the timetable, overnight
DL 5845 leaves 22 h 44 after UA 1665 arrives on the timetable: more than half a day, so not a connection we count.