The present invention relates to an enantiomerically pure (+)-trans-enantiomerof a compound represented by the following formula (I): wherein R,R, R, R and R are as defined in thespecification； enantiomerically pure intermediates thereof, to processesfor the preparation of the enantiomerically pure compound and its intermediates,and to a pharmaceutical composition comprising the enantiomerically pure compound.The compound of formula (I) is useful for the treatment of diseases or disordersmediated by the inhibition of cyclin dependant kinase, such as cancer.
