A compound represented by the general formula: ##STR1## wherein Y represents a nitrogen atom or C--G (G represents a carboxyl group which may be esterified); ring R is a nitrogen-containing unsaturated heterocyclic group which may be substituted for; each of rings A and B may have a substituent; n represents an integer from 1 to 4; k represents the integer 0 or 1, or a salt thereof, which serves well as an anti-inflammatory agent, particularly a therapeutic agent for arthritis.