The present invention provides novel pyrimidine amines of formula I which are potent inhibitors of spleen tyrosine kinase, and are useful in the treatment and prevention of diseases mediated by said enzyme, such as asthma, COPD, rheumatoid arthritis, and cancer.本発明は、強力な脾臓チロシンキナーゼ阻害薬であり、前記酵素によって媒介される疾患、例えば、喘息、COPD、関節リウマチおよびがんの処置および予防に有用な式Iの新規なピリミジンアミンを提供する。