OZ 6344 then UA 8187 at San Francisco
St Louis → San Francisco → Washington National
Timetable, San Francisco time
21:41OZ 6344 from St Louis at the gate
15:23UA 8187 to Washington National leaves the gate
17 h 42 apart on the timetable, overnight
UA 8187 leaves 17 h 42 after OZ 6344 arrives on the timetable: more than half a day, so not a connection we count.