UA 2101 then B6 8353 at Boston
Chicago O'Hare → Boston → New York JFK
Timetable, Boston time
17:24UA 2101 from Chicago O'Hare at the gate
06:00B6 8353 to New York JFK leaves the gate
12 h 36 apart on the timetable, overnight
B6 8353 leaves 12 h 36 after UA 2101 arrives on the timetable: more than half a day, so not a connection we count.