São Paulo is 6.5 hours behind Tehran
Best overlap: 2:30 PM to 6:30 PM in Tehran is 8:00 AM to 12:00 PM in São Paulo.
If you set up a recurring sync, 2:30 PM to 6:30 PM in Tehran (8:00 AM to 12:00 PM in São Paulo) is the natural home for it. You share roughly 4 hours a day. That's enough for regular meetings, but treat the window as prime time and guard it.