The formula (I):
wherein each of R
2
and R
3
is, same or different, C2-C4 alkyl or the like; or R
2
and R
3
are taken together with the adjacent carbon atom to form a 5 to 8 membered non-aromatic carbocyclic ring; R
4
is C1-C6 alkyl or the like; X is an oxgen atom or a sulfur atom; A is the group of the formula:
wherein R
1
is, same or different, alkyl or the like; W is C2-C6 alkylene which may contain an optionally substituted heteroatom(s) or the like; n is an integer of 0 to 7, a pharmaceutically acceptable salt, or a solvate thereof.
The formula (I):
wherein each of R2 and R3 is, same or different, C2-C4 alkyl or the like; or R2 and R3 are taken together with the adjacent carbon atom to form a 5 to 8 membered non-aromatic carbocyclic ring; R4 is C1-C6 alkyl or the like; X is an oxgen atom or a sulfur atom; A is the group of the formula:
wherein R1 is, same or different, alkyl or the like; W is C2-C6 alkylene which may contain an optionally substituted heteroatom(s) or the like; n is an integer of 0 to 7, a pharmaceutically acceptable salt, or a solvate thereof.