Combine sugar, butter and syrup in a saucepan and heat until melted. Bring to a boil. Pour into a 9 x 13 inch glass baking dish. Place bread slices on top of syrup. Combine milk, eggs, salt and vanilla. Whisk to blend. Pour over bread and sprinkle with cinnamon, refrigerate overnight. Bake at 350 degrees for 40 minutes or until golden brown and puffy. Serve immediately.