| abstract |
This invention provides a compound represented by formula (1) or a pharmaceutically acceptable salt thereof. Specifically, the present invention provides a compound represented by formula (1) or a pharmaceutically acceptable salt thereof [Therein, A is O, S, or N—R 6 ; ring G is a 5-membered or 6-membered aromatic ring, etc., including 1-3 heteroatoms selected from O, S and N as constituent atoms; R 1 and R 2 are each independently a hydrogen atom, a halogen atom, or an optionally-substituted C 1-6 alkyl carbonyl group, etc.; R 3 , R 4 and R 5 are each independently a hydrogen atom, a halogen atom, or an optionally-substituted C 1-6 alkyl carbonyl group, etc.; and R 6 is a hydrogen atom or an optionally-substituted C 1-6 alkyl group, etc.]. |