A purpose of the present invention is to provide TNF-.alpha. production inhibitors being useful as therapeutic agents for autoimmune diseases such as rheumatoid arthritis. Novel compounds having the structure represented by the general formula [1] or salts thereof according to the present invention have excellent TNF-.alpha. production inhibitory activities, ##STR00001## wherein A is --(NR.sup.4)--, --(CR.sup.5R.sup.6)-- or --O--, B is alkylene or alkenylene, R.sup.1, R.sup.2, R.sup.4, R.sup.5 and R.sup.6 are hydrogen, alkyl, alkenyl, adamantyl or the like, R.sup.3 is aryl or an unsaturated heterocycle, and X is oxygen or sulfer respectively.