Compounds of the formulae: STR1 wherein, Z and Y are each alkylene or oxy-alkylene containing one to about five carbon atoms in the principal chain or said alkylene substituted with OH, alkanoyloxy, alkoxy, mercapto or alkylmercapto; each of R1, R2 and R3 is independently H, alkyl, aryl, halo, alkoxy, alkenyloxy, alkylsulfinyl, alkylsulfonyl, alkylmercapto, cyano, carboxy, carbalkoxy, carboxamido, sulfamoyl, trifluoromethyl, hydroxy, hydroxyalkyl, acyloxy, alkylamino, sulfonylamino, or acylamino; or R1 and R2, when taken together, form a methylenedioxy or --O--CO--O--; Ar is heteroaryl, cycloalkyl or STR2 wherein, R1, R2 and R3 are as hereindescribed; and R is H, alkyl, cycloalkyl, aryl, aralkyl, alkenyl, alkynyl, carboalkoxy, or CONR4 R5 wherein each of R4 and R5 is H or alkyl; wherein the total number of carbon atoms in each hydrocarbyl group is up to 10; and STR3 wherein, each of R1 and R2 is independently H, alkyl, aryl, halo, alkoxy, alkenyloxy, alkylsulfinyl, alkylsulfonyl, alkylmercapto, cyano, carboxy, carbalkoxy, carboxamido, sulfamoyl, trifluoromethyl, hydroxy, hydroxyalkyl, acyloxy, alkylamino, sulfonylamino, or acylamino; or R1 and R2, when taken together, form a methylenedioxy, or --O--CO--O--; R6 is H, alkyl, aryl, halo, alkoxy, alkenyloxy, alkylsulfonyl, alkylmercapto, cyano, carboxy, carbalkoxy, carboxamido, sulfamoyl, trifluoromethyl, hydroxy, hydroxyalkyl, acyloxy, alkylamino, sulfonylamino or acylamino; wherein the total number of carbon atoms in each hydrocarbyl group is up to 10; and acid addition salts thereof have selective cardiotonic, antihypertensive and antiallergic activity.