B6 387 then UA 771 at LAX
Boston → Los Angeles → Beijing
Timetable, Los Angeles time
00:55B6 387 from Boston at the gate
23:35UA 771 to Beijing leaves the gate
22 h 40 apart on the timetable
UA 771 leaves 22 h 40 after B6 387 arrives on the timetable: more than half a day, so not a connection we count.