om 7 to 12 carbon atoms such as benzyl or phenylethyl, nitro and the like, (8) aralkyl-carbonyl having from 7 to 12 carbon atoms such as benzylcarbonyl or phenethylcarbonyl, which may have 1 to 4 substituent(s) selected from a halogen atom such as chlorine, bromine, or fluorine, alkyl having from 1 to 6 carbon atoms such as methyl, ethyl, or n-propyl, aryl having from 6 to 10 carbon atoms such as