A compound selected from those of formula (I): ##STR00001## wherein: W.sub.1 represents, together with carbon to which it is bonded, phenyl, pyridyl, Z represents a group of formula U--V as defined in the description, Q.sub.1 represents oxygen, NR.sub.2 as defined in the description, Q.sub.2 represents oxygen, NR'.sub.2 as defined in the description, X.sub.1, X.sub.2, X'.sub.1 and X'.sub.2 each represents hydrogen, hydroxy, alkoxy, mercapto or alkylthio, Y.sub.1, Y.sub.2, Y'.sub.1 and Y'.sub.2 each represents hydrogen, or X.sub.1 and Y.sub.1, X.sub.2 and Y.sub.2, X'.sub.1 and Y'.sub.1, X'.sub.2 and Y'.sub.2 with carbon carrying them, together form carbonyl or thiocarbonyl, R.sub.1 is as defined in the description, its isomers, and addition salts thereof with a pharmaceutically acceptable acid or base, and medicinal products containing the same which are useful in the treatment of cancer.