The present invention relates to a compound represented by a formula (I): wherein R1 represents a halogen atom or the like R2 represents a hydrogen atom or the like R3 and R4 each independently represents lower alkyl R5 represents phenyl or the like R6 represents a halogen atom or the like m is an integer of from 0 to 2 p is an integer of from 1 to 4 and q is an integer of from 1 to 5 as an inhibitor of DGAT1 and its use for the treatment of hyperlipidemia etc.
