Formula (I) [R 1 , R 2 , R 3 At least one group of the cyclic alkyl group of the remaining alkyl group linear or branched n is 0 or 1 R 4 Amino group or - (. CX 2 ..) m -COOH (M is 0~3, X is a hydrogen atom ) R 5 Is - (. CY 2 ..) p -COOR 6 (p is 0~3, Y is a hydrogen atom , R 6 is a hydrogen atom or an alkyl group ) The compound or a salt thereof式(I)[R1、R2、R3のうちの少なくとも1つの基は環状アルキル基、残りの基は直鎖若しくは分枝鎖のアルキル基;nは0又は1;R4はアミノ基又は-(CX2)m-COOH(mは0~3、Xは水素原子);R5は-(CY2)p-COOR6(pは0~3、Yは水素原子、R6は水素原子又はアルキル基)]で表される化合物又はその塩