These heterocyclic rings may be substituted by alkyl groups having 1 to 4 carbon atoms such as a methyl group or an ethyl group, etc., alkoxy groups having 1 to 4 carbon atoms such as a methoxy group or an ethoxy group, etc., aryl groups having 6 to 18 carbon atoms such as a phenyl group, etc., halogen atoms such as chlorine or bromine, etc., alkoxycarbonyl groups, a cyano group and an amido group