The invention provides compounds of the formula:R<；sup>；1<；/sup>；is OR<；sup>；11<；/sup>；, or NR<；sup>；5<；/sup>；R<；sup>；5'<；/sup>；；R<；sup>；2<；/sup>；is F；R<；sup>；5<；/sup>；is H, C<；sub>；1<；/sub>；-C<；sub>；6<；/sub>；alkyl, OH, C(=O)R<；sup>；6<；/sup>；, O(C=O)R<；sup>；6<；/sup>；or O(C=O)OR<；sup>；6<；/sup>；；R<；sup>；5'<；/sup>；is H or C<；sub>；1<；/sub>；-C<；sub>；6<；/sub>；alkyl；R<；sup>；6<；/sup>；is C<；sub>；1<；/sub>；-C<；sub>；22<；/sub>；alkyl or C<；sub>；3<；/sub>；-C<；sub>；7<；/sub>；cycloalkyl；R<；sup>；13<；/sup>；is H, phenyl, pyridyl, benzyl, indolyl or naphthyl wherein the phenyl, pyridyl, benzyl, indolyl and naphthyl is optionally substituted with 1, 2 or 3 R<；sup>；22<；/sup>；；and the other variables are as defined in the claims,which are of use in the treatment of cancer, and related aspects.
