A compound of formula (I) wherein Y is oxygen or sulfur, and X 1 , X 2 and X 3 are independently hydrogen, halogen, hydroxy or linear or branched (C 1-6 )alkyl, or hydroxy-(C 1-6 )alkyl or (C 1-6 )alkoxy-(C 1-6 )alkyl, mono- or dihalogenated (C 1-6 )alkyl, amino-(C 1-6 )alkyl, hydroxy-(C 1-6 )alkyl, with the provisos that (1) at least one of X 1 , X 2 and X 3 is not hydrogen, and (2) X 2 is not hydroxy when X 1 and X 3 are hydrogen are useful in the treatment of diseases mediated by microbes.
