First off, Nineveh, the capital of Assyria, is located inside the modern city of Mosul, Iraq.
Now granted modern Syria and Iraq are artificial creations so one must look beyond simple borders. Looking at the people it is clear Assyria does not equal Syria. Assyrians exist today. Most are either Chaldean Catholic or Nestorian Church of the East. While there are some Assyrians in Syria (500,000 out of 22,500,000), most Syrians are Arab.
Finally, Assyria ceased to be as an independent power in 605 BC. Syria became in 1946.
The land, people, and time do not match. Assyria is not Syria.