Preheat oven to 350 degrees. In a medium saucepan, melt the butter, add the maple syrup, brown sugar and cinnamon. Bring to a boil, add pretzels, turn off heat. Toss to coat pretzels. Line a baking sheet with foil, place pretzels on the lined sheet. Bake for 6-8 minutes, stirring every 2 minutes. (Watch carefully so they do not burn) Cool.