| abstract |
The invention provides a compound having the formula (1): n n n n n n n n n n and salts thereof; wherein:n nR 1 is hydrogen or C 1-2 alkyl; andn nR 2 , R 3 and R 4 are the same or different and each is selected from hydrogen, C 1-2 alkyl, fluorine, chlorine, C 1-2 alkoxy and trifluoromethyl, provided that no more than two of R 2 , R 3 and R 4 are other than hydrogen.n n Also provided are pharmaceutical compositions containing the compounds and their use in medicine, and in particular in the treatment of cancer. |