Novel compounds of formula ##STR1## are described which have antipyretic, analgesic and antiinflammatory activity. R is hydrogen, C.sub.1 -C.sub.3 linear or branched alkyl; R.sub.1 and R.sub.2 are hydrogen, halogen, unsubstituted or esterified hydroxy, alcoxy, and may be the same or different; R.sub.3 is hydrogen, C.sub.1 -C.sub.4 linear or branched aliphatic acyl, unsubstituted or substituted aroyl, alkylaroyl or hetaroyl groups.