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.