ng A, E, D, G, and L. The letters a, c, f, and h represent integers ranging from 1 to 5; e and j are each integers ranging from 0 to 25, with ranges from 0 to 7 being preferably and 1-7 being most preferred; and k is an integer of 0 or 1 with the proviso that k must be 0 when A is S or O. R is a member selected from the group consisting of lower alkyl and substituted lower alkyl.