R5 271 then JU 423 at Istanbul
Amman → Istanbul → Belgrade
Timetable, Istanbul time
19:15R5 271 from Amman at the gate
16:40JU 423 to Belgrade leaves the gate
21 h 25 apart on the timetable, overnight
JU 423 leaves 21 h 25 after R5 271 arrives on the timetable: more than half a day, so not a connection we count.