| abstract |
Disclosed is a compound represented by the general formula (I) or a salt thereof: (I) wherein any one of R1, R2 and R3 represents a group represented by the formula: -(CH2)m-NR11R12 (wherein m is 1 or 2; and R11 and R12 independently represent a hydrogen atom or a C1-6 alkyl group or may, together with a nitrogen atom to which R11 and R12 are bound, form a 4- or 5-membered cyclic group); the remaining two of R1, R2 and R3 independently represent a group represented by the formula: -(O)n-R21 (wherein n is 0 or 1; and R21 represents a hydrogen atom, a C1-6 alkyl group, a C2-6 alkenyl group, a C2-6 alkynyl group, or the like); and R4 represents a C1-6 alkyl group which may have a substituent or the like. |