Compounds of formula (I) which exhibit excellent immune suppression activity, pharmacologically acceptable salts thereof, esters thereof or other derivatives:
1
wherein R
1
and R
2
are a hydrogen atom, an amino protecting group; R
3
is a hydrogen atom, a hydroxy protecting group; R
4
is a lower alkyl group; n is an integer from 1 to 6; X is an ethylene group; Y is a C
1
-C
10
alkylene group, a C
1
-C
10
alkylene group substituted with 1 to 3 substituents selected from substituent group a and b; R
5
is an aryl group; R
6
and R
7
are a hydrogen atom, a group selected from substituent group a; with the proviso when R
5
is a hydrogen atom, Y is not a single bond or a straight chain C
1
-C
10
alkylene group.