Compounds having the following structure (I):or a stereoisomer, tautomer or pharmaceutically acceptable salt thereof, wherein one of R1, R2 or R3 is —；P(═；O)(OH)2, and the other two of R1, R2 and R3 are each H, are provided. Pharmaceutical compositions comprising the compounds, and methods for use of the compounds for treating diseases associated with overexpression of a cyclin-dependent kinase (CDK) are also provided.
