UA 3851 then AA 597 at San Francisco
Rio De Janeiro → San Francisco → Chicago O'Hare
Timetable, San Francisco time
17:41UA 3851 from Rio De Janeiro at the gate
17:22AA 597 to Chicago O'Hare leaves the gatealso QF 4712
23 h 41 apart on the timetable, overnight
AA 597 leaves 23 h 41 after UA 3851 arrives on the timetable: more than half a day, so not a connection we count.