AA 517 then UA 1665 at San Francisco
Chicago O'Hare → San Francisco → Boston
Timetable, San Francisco time
11:11AA 517 from Chicago O'Hare at the gatealso QF 4687
23:20UA 1665 to Boston leaves the gatealso VA 8306, NZ 9018
12 h 09 apart on the timetable
UA 1665 leaves 12 h 09 after AA 517 arrives on the timetable: more than half a day, so not a connection we count.