This invention provides a compound of formula (I): wherein R1 represents an alkyl group having from 1 to 4 carbon atoms or a halogen atom, R2 represents an alkyl group having from 1 to 4 carbon atoms, R3 represents a hydrogen atom or a hydroxy group, and A represents an oxygen atom or a group of the formula —C(R4)(R5)— (in which R4 represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms and R5 represents a hydroxy group or an alkoxy group having from 1 to 4 carbon atoms) or a pharmaceutically acceptable salts thereof. These compounds have 5-HT4 receptor agonistic activity, and thus are useful for the treatment of gastroesophageal reflux disease, non-ulcer dyspepsia, functional dyspepsia, irritable bowel syndrome or the like in mammalian, especially humans.