abstract |
The present invention provides a compound represented by formula (I). Formula (I): In formula (I), R < 1> and R < 2> represents a hydrogen atom or an alkyl group each independently. R 3 is -SO 3 H, -SO 3 - M +, -CO 2 H or -CO 2 - shows an M +. M + represents (R 11 ) 4 N + , Na + or K + . R 11 represents a hydrogen atom, an alkyl group or an aralkyl group. m represents the integer of 0-2. n and p each independently represent an integer of 0 to 2; |