UA 2 then DL 2112 at San Francisco
Singapore → San Francisco → New York JFK
Timetable, San Francisco time
09:15UA 2 from Singapore at the gate
21:35DL 2112 to New York JFK leaves the gatealso AM 4443, VS 4856
12 h 20 apart on the timetable
DL 2112 leaves 12 h 20 after UA 2 arrives on the timetable: more than half a day, so not a connection we count.