The compounds prepared in this SAR investigation are listed in Tables I-IV and are arranged according to modifications of the substituent X in position 1 which ranges from hydrogen to lower alkyl, trifluoromethyl, pentafluoroethyl, phenyl, methoxy, and hydroxy. Modification of substituent Y in the 4-position is explored within such subgroups and ranges from NH2 to acylated and mono-or dialkylated amines. Substituents 2 in the 6-, 7-, and 8- ...