Patent ID: 8546586

Claim:
A compound represented by the general formula [1] or a salt thereof: wherein R 1 to R 6 each independently represent: an alkyl group; an alkyl group substituted by a group represented by the general formula [101]: wherein R 101 to R 104 each independently represent a hydrogen atom or a C 1 to C 3 alkyl group and m represents an integer from 2 to 6, or two or three of R 102 to R 104 together with a nitrogen atom to which they are bound may form a heterocyclic ammonium cation; an alkyl group substituted by a group represented by the general formula [2] and which optionally contains an amide bond: —COOR 12 [2] wherein R 12 represents a hydrogen atom, a C 1 to C 10 alkyl group, an alkali metal atom, an organic ammonium ion, or an ammonium ion or anion; or an alkyl group substituted by a group represented by the general formula [3] and which optionally contains an amide bond: —SO 3 R 13 [3] wherein R 13 represents a hydrogen atom, an alkali metal atom, an organic ammonium ion, an ammonium ion or anion; R 7 to R 10 each independently represent an alkyl group, an alkynyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylsulfonyl group, an arylsulfonyl group, an amino group, a group represented by the general formula [2], a group represented by the general formula [3], a halogen atom, a hydrogen atom, a hydroxyl group, a cyano group or a nitro group; R 11 represents a hydrogen atom, an alkyl group, an alkynyl group or an aryl group, and n represents an integer from 0 to 3, wherein at least one of R 1 to R 6 is an alkyl group substituted by a group represented by the general formula [101].