Patent ID: 8222274

Claim:
A compound represented by formula (I) or a pharmaceutically acceptable salt thereof wherein R 1 is —N═C(NH 2 ) 2 , —N(R 0 )-(nitrogen-containing saturated heterocyclic group which has a linkage on a carbon atom as the ring atom and may be substituted), —N(R 0 ) lower alkylene-N(lower alkyl) 2 , —N(R 0 )-lower alkylene-(nitrogen-containing saturated heterocyclic group which may be substituted), —N(R 0 )-lower alkylene-(heterocyclic group substituted with —N(lower alkyl) 2 ) or —N(R 0 )-lower alkylene-(cycloalkyl substituted with —N(lower alkyl) 2 ); R 0 is independently —H or lower alkyl; R 3 is lower alkyl; R 4 is lower alkyl; R 5 is —H or lower alkyl; and R 2 is —(CH 2 ) 2 )-(phenyl which may be substituted with halogen).