This invention provides compounds of formula I, ##STR1## wherein R.sub.1 is alkyl of 1 to 10 carbon atoms, cycloalkyl of 3 to 8 carbon atoms or phenyl, and R.sub.2 is hydrogen or alkyl of 1 to 4 carbon atoms, Useful as anti-phlogistics, anti-pyretics, analagesics and inhibitors of blood platelet aggregation.