. . . "Examples of the group R include hydrogen atoms or methyl groups, as well as lower alkyl groups of 2 to 5 carbon atoms, or more specifically, straight chain or branched alkyl groups such as ethyl groups, propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, tert-butyl groups, pentyl groups, isopentyl groups and neopentyl groups." . . . .