The present invention provides a pyrazolopyrimidinederivative represented by formula (I)(see formula I){wherein R1 represents ¨NR1a R1b (wherein R1a and R1b are the same ordifferent and each is a hydrogen atom, aralkyl, or the like), orthe like,R2 represents formula (Ya) (Ya)[wherein k and m each represents an integer of 0 - 2, n representsan integer of 0 - 4, L represents a single bond or the like, R5represents halogen or the like, R6 represents aryl or the like, Xrepresents -CR8 (wherein R8 represents a hydrogen atom or the like),or the like, and R7 represents a hydrogen or the like], or thelike,R3 represents ¨SO2R13a [wherein R13a represents lower alkoxy, -NR13d C(=O)R13e (wherein R13d represents a hydrogen atom or the like,and R13e represents lower alkyl or the like), or the like], or thelike, andR4 represents a hydrogen atom or the like}, or a pharmaceuticallyacceptable salt thereof, which compound may be used in thepreparation of an agent, which might potentially be used for skindiseases.
