Brasília is 6 hours behind Istanbul
Best overlap: 2:00 PM to 6:00 PM in Istanbul is 8:00 AM to 12:00 PM in Brasília.
For a call that suits both sides, look at 2:00 PM to 6:00 PM in Istanbul / 8:00 AM to 12:00 PM in Brasília. With 4 hours of overlap, 2:00 PM in Istanbul (8:00 AM in Brasília) is a comfortable, repeatable slot for both sides.