Place 8 ounces pitted prunes, 1 cup dry red wine, 2 tablespoons granulated sugar, and 1/2 teaspoon ground cinnamon in a small saucepan. Bring to a boil over medium-high heat. Reduce the heat to maintain a simmer and cook until the wine reduces but still covers the prunes about 3/4 of the way up, about 5 minutes.