The present invention relates to compounds of formula (I),wherein Ra, Rb, Rc, Rd, Re and Rf are as defined in the specification, processes for their preparation, pharmaceutical compositions containing them and their use in the treatment of diseases mediated by phosphatidylinositol-3-kinase (PI3K), mammalian target of rapamycin (mTOR), Signal transducer and activator of transcription 3 (STAT 3), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) or a combination thereof particularly in the treatment of cancer and inflammation.
