A compound of formula (1) ##STR1## wherein X.sup.1 is amino or hydroxyl, X.sup.2 is carbonyl and the like R.sup.1 is an alkyl, an aryl and the like, R.sup.2 is hydrogen and the like, and R.sup.3 is an alkyl and the like, or a pharmaceutical acceptable salt thereof is effective for inibiting the production and/or secretion of tumor necrosis factor in a patient in need of such inhibition.