The present invention relates to a compound or a pharmacologically acceptable salt thereof having an excellent glucose lowering effect.A compound represented by the following general formula (I) or a pharmacologically acceptable salt thereof: wherein R1 represents a C1-C3 alkyl group, each substituent R2 may be the same or different and may each represent a C1-C3 alkyl group, R3 represents an optionally substituted pyridyl group or the like, R4 and R5, which are the same or different, each represent a C1-C3 alkyl group, R6 and R7, which are the same or different, each represent a C1-C3 alkyl group, and n represents 0 to 3.