The present invention relates to compounds of formula (I): wherein R1 is hydroxy, C1-4 alkoxy, amino, C1-4 alkyl-amino, di C1-4alkylamino, benzyloxy or C2-C7 alkanoyl, R2 is C1-4 alkyl, C1-4 alkoxy, C1-4 alkoxy C1-4alkoxy, CF3, halogen, C1-4alkylamino, di C1-4alkylamino, di C1-4 alkylamino C1-4 alkoxy or N—C1-4 alkoxy C1-4 alkyl-N—C1-4 alkylamino, N—C1-4 alkyl-piperazinyl, morpholinyl or pyrrolidinyl-C1-4 alkoxy, wherein the C1-4 alkyl radicals in R2 are optionally further substituted by C1-4 alkyl, halogen, cyano, amino, alkoxy or alkylthio, X is N or O, Y is N, O or CH, Z is N or CH, and W is N or CH, provided that (a) R1 is not hydroxy or C1-4 alkoxy when R2 is CF3, X is O, Y is CH, Z is N and W is CH, (b) R1 is not hydroxy or C1-4 alkoxy when R2 is CF3 or chloro, X is N, Y is O, Z is CH and W is CH, (c) R1 is not hydroxy when R2 is CF3, X is O, Y is N, Z is CH and W is CH and (d) X and Y are not simultaneously O, the salts thereof; their preparation, their use and pharmaceutical compositions containing them.