A compound of the formula:
wherein
Ar is optionally substituted phenyl, etc.; n is 0, 1 or 2;
R1 is hydogen atom, optionally substituted alkyl, etc.; R2 and R3 are independently optionally substituted alkyl, etc.;
R4 and R5 are independently hydrogen atom or optionally substituted alkyl; R6 is hydrogen atom, hydroxy or alkyl;
or a pharmaceutically acceptable salt thereof is useful as a medicament for treating retinal degenerative disorders and the like.
A compound of the formula:
wherein
Ar is optionally substituted phenyl, etc. ; n is 0, 1 or 2;
R1 is hydogen atom, optionally substituted alkyl, etc. ; R2 and R3 are independently optionally substituted alkyl, etc. ;
R4 and R5 are independently hydrogen atom or optionally substituted alkyl; R6 is hydrogen atom, hydroxy or alkyl;
or a pharmaceutically acceptable salt thereof is useful as a medicament for treating retinal degenerative disorders and the like.