| abstract |
The invention relates to substantially pure compounds of the formula (1) and to pharmaceutically acceptable salts, prodrugs and solvates thereof, wherein R, R 1 , R 2 , R 3 , R 4 , and R5 are as defined herein. The invention also relates to pharmaceutical compositions comprising the compounds of formula (1) and methods of treating abnormal cell growth, such as cancer, in mammals by administering such pharmaceutical formulations. |