A compound represented by the formula ##STR1## wherein R.sup.1 represents a hydroxyl group, an alkanoyloxy group or a group of the formula ##STR2## in which R.sup.2 represents a hydrogen atom or a lower alkyl group, and R.sup.3 represents a hydrogen atom, a lower alkyl group, an alkanoyl group, a phenyl group, a carbamoyl group or a thiocarbamoyl group, or a salt thereof.The said compound can be prepared by reacting a compound represented by the formula ##STR3## with a compound of the formulaNH.sub.2 --R.sup.1 (III)wherein R.sup.1 is as defined hereinabove, or a salt thereof, and as required, alkanoylating the resulting compound of formula (I) in which R.sup.1 represents a hydroxyl group or an amino group, and as required, converting the resulting compound of formula (I) in which R.sup.1 is the group ##STR4## into its salt, and is useful for the treatment of inflammation, pain or rheumatism.