The present invention relates to selective inhibitors of phosphoinositide (PI) 3-kinase .beta., use of the selective inhibitors in anti-thrombotic therapy, and a method for screening compounds useful for the new anti-thrombotic therapy by detecting selective inhibitory activity of PI 3-kinase .beta. of the compound. The invention also relates to novel compounds of formula II that are inhibitors of PI 3-kinase. (see formula I)
