The present invention relates to a compound of the formula (I)wherein R1 isbenzofuranyl substituted by halogen, or styryl substituted by halogen; R2 issubstituted hydroxy, substituted mercapto or substituted sulfonyl; and X is orpharmaceutically acceptable salts thereof. The compound (I) of the presentinvention and pharmaceutically acceptable salts thereof possess a stronginhibitory activity on the production of nitric oxide (NO), and are useful forprevention and/or treatment of NO-mediated diseases in human being and animals.