In a nonreactive saucepan, combine 3/4 cup of the sugar with the brandy, lemon zest, cinnamon stick, vanilla bean, star anise, cloves, and 1 1/2 cups of water. Bring to a boil over high heat, then add the pears. Lower the heat, set a plate on the pears to submerge them and simmer until tender, about 3 minutes. Transfer the pears to a plate to cool. Boil the liquid until reduced to a syrup, about 4 minutes. Strain and let cool.