A compound of the formula: ##STR00001## wherein R.sup.1 is an aliphatic hydrocarbon group optionally having substituent(s), an aromatic hydrocarbon group optionally having substituent(s), a heterocyclic group optionally having substituent(s), a group of the formula: OR.sup.1a wherein R.sup.1a is a hydrogen atom or an aliphatic hydrocarbon group optionally having substituent(s), or a group of the formula: ##STR00002## wherein R.sup.1b and R.sup.1c are the same or different and each is a hydrogen atom or an aliphatic hydrocarbon group optionally having substituent(s), X is a methylene group, a nitrogen atom, a sulfur atom or an oxygen atom, Y is an optionally substituted methylene group or an optionally substituted nitrogen atom, ring A is a 5 to 8-membered ring optionally substituted further by 1 to 4 substituent(s) selected from (1) an aliphatic hydrocarbon group optionally having substituent(s), (2) an aromatic hydrocarbon group optionally having substituent(s), (3) a group of the formula: OR.sup.2 wherein R.sup.2 is a hydrogen atom, or an aliphatic hydrocarbon group optionally having substituent(s) and (4) a halogen atom, Ar is an aromatic hydrocarbon group optionally having substituent(s), a group of the formula: ##STR00003## is a group of the formula: ##STR00004## or the formula: ##STR00005## m is an integer of 0 to 2, n is an integer of 1 to 3, and the sum of m and n is not more than 4, provided that when X is a methylene group, Y is an optionally substituted methylene group, and a salt thereof have an inhibitory activity on nitric oxide (NO) production and cytokine production, and are useful as an agent for the prophylaxis and/or treatment of diseases, such as cardiac disease, autoimmune disease, inflammatory disease, central nervous system disease, infectious disease, sepsis, septic shock and the like.