UA 582 then UA 785 at San Francisco
Boston → San Francisco → Washington
Timetable, San Francisco time
12:09UA 582 from Boston at the gate
06:15UA 785 to Washington leaves the gatealso AZ 4408, NZ 9160
18 h 06 apart on the timetable, overnight
UA 785 leaves 18 h 06 after UA 582 arrives on the timetable: more than half a day, so not a connection we count.