ET 3608 then UA 516 at O'Hare
Anchorage → Chicago → St Louis
Timetable, Chicago time
07:16ET 3608 from Anchorage at the gate
20:10UA 516 to St Louis leaves the gate
12 h 54 apart on the timetable
UA 516 leaves 12 h 54 after ET 3608 arrives on the timetable: more than half a day, so not a connection we count.