By what means did europeans get leaders in the middle east to sign treaties?

Answer 1

It depends on the treaty.

Some treaties were mutually beneficial agreements and the inducements in the treaty itself (such as an alliance between France and the Ottoman Empire, or trade between the Seljuks and Venice) were enough to compel to the Middle Eastern leader in question to sign.

Some treaties were the result of wars and those would be signed as a result of the way the various battles had gone. For example, after the Battle of Mohacs and several other battles, Hungary was forced to sign a treaty surrendering to the Ottomans. When the Ottoman Empire lost the Wars of Greek Reunification, they were forced by those battle conditions to sign treaties surrendering land to the Greeks.

Some treaties were to allow imperialist European powers to create colonies, mandates, or protectorates in the Middle East. Sometimes a brilliant show of force or a strong threat would be enough. Sometimes the fear of a worse offer or protecting a state from a local adversary would compel signage.

Bottom line, it depends on the treaty.

Answer 2

Some treaties were signed by the leader in the middle east as a way to end wars. Other treaties may have been signed because they would benefit the middle east.