The present invention relates to compounds of formula (I)
wherein:
Ar1 or Ar2 is an optionally substituted indole, and the other group is an optionally substituted aromatic or heteroaromatic group, preferably an optionally substituted indole,
X is O or S, and
R2 is H, hydroxy, amino, C1-6alkyl, hydroxyC1-6alkyl or aminoC1-6alkyl,
and salts and solvates thereof and solvates of such salts,
and the use of such compounds in medical therapies.