oms; for example, acetylamino and benzoylamino), an alkoxycarbonylamino group (preferably having from 2 to 30 carbon atoms, more preferably from 2 to 20 carbon atoms, and especially preferably from 2 to 12 carbon atoms; for example, methoxycarbonylamino), an aryloxycarbonylamino group (preferably having from 7 to 30 carbon atoms, more preferably from 7 to 20 carbon atoms, and especially preferably