Patent ID: 8642770

Claim:
A compound represented by the formula wherein ring AB is an indole ring; R 1 is an optionally substituted C 1-6 alkoxy group, an optionally substituted C 1-6 alkyl group, an optionally substituted C 2-6 alkenyl group, or an optionally substituted C 2-6 alkynyl group; R 2 is a hydrogen atom or a fluorine atom; R 3 is a hydrogen atom, a halogen atom or a C 1-6 alkyl group; R 4 and R 5 are each independently a hydrogen atom or a methyl group; R 6 is a hydrogen atom or a methyl group; and (1) R 7 is a hydrogen atom or a C 1-6 alkyl group; and R 8 is an optionally substituted C 1-6 alkyl group, an optionally substituted C 3-10 cycloalkyl group, or an optionally substituted 4- to 7-membered saturated heterocyclic group; or (2) R 7 and R 8 optionally form, together with the adjacent nitrogen atom, an optionally substituted 4- to 7-membered nitrogen-containing heterocycle, or a salt thereof.