Abstract: Compounds of the structure: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, and R.sub.6 are hydrogen, alkyl, alkenyl, alkynyl, phenyl-alkyl, or cycloalkyl,n is an integer from 0 to 4 inclusive,M is heterocyclic or heterocyclic alkyl,Y is hydroxy, alkoxy, amino, or substituted amino, amino-alkanoyl, aryloxy, aminoalkoxy, or hydroxyalkoxy, andR.sub.7 is hydrogen, alkanoyl, carboxylalkanoyl, hydroxyalkanoyl, amino-alkanoyl, cyano, amidino, carbalkoxy, ##STR2## wherein Z is hydrogen, alkyl, hydroxyalkyl, aminoalkyl or the radical ##STR3## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, n, M and Y are as described above; and where Y is hydroxy their nontoxic, pharmaceutically acceptable alkali metal, alkaline earth metal, and amine salts.