There are described compounds of formula I, ##STR1## in which either R.sub.2 represents hydrogen, alkyl or Ar.sub.2, andR.sub.3 represents hydrogen, alkyl or alkyl substituted by Ar.sub.3 ;or R.sub.2 and R.sub.3 together form the chain --(CH.sub.2).sub.m --;R.sub.4 and R.sub.5, which may be the same or different, each independently represent hydrogen, halogen, Ar, alkyl, or alkyl substituted by Ar,Ar.sub.1, Ar.sub.2 and Ar, which may be the same or different each independently represent aryl or aryl substituted by one or more ofhalogen, hydroxy, --CN, --COR.sub.6, trihalomethyl, alkoxy, alkoxy substituted by --COR.sub.6, alkoxy substituted by --NR.sub.7 R.sub.8, alkyl, alkyl substituted by --COR.sub.6, alkyl substituted by NR.sub.7 R.sub.8, alkoxy substituted by Ar.sub.3, S(O).sub.n R.sub.9, --NR.sub.7 R.sub.8 or OAr.sub.3 ;R.sub.6 represents --OR.sub.10, --NR.sub.7 R.sub.8, hydrogen or alkyl;R.sub.7 and R.sub.8, which may be the same or different, each independently represent hydrogen, alkyl, alkanoyl or Ar.sub.3 ;R.sub.9 represents alkyl or Ar.sub.3 ;R.sub.10 represents hydrogen, alkyl or Ar.sub.3 ;m represents an integer from 3 to 6 inclusive;n represents 0, 1 or 2; andAr.sub.3 represents unsubstituted aryl;or a pharmaceutically acceptable derivative thereof.There are also described compositions containing the compounds and methods for their preparation.The compounds are indicated for use as pharmaceutical, e.g. anti-inflammatory, agents.