A compound represented by the general formula [I] (wherein R1 is a C1 - C6 alkyl group R2 is a C1 - C6 alkylsulfonyl group and the like R3 and R4are each independently hydrogen or a C1 - C6 alkyl group R5 is hydrogen or a benzyl group or the like R7, R8 , R9 and R10 are each independently hydrogen or a C1 - C6 alkyl group. ) or a herbicide containing a salt thereof, intermediate preparing therefor, and the said compound.