Production method for 3, 3-dimethyl-3, 4-dihydro-1h-quinoxaline-2-one derivative and intermediate for said production method

To provide: a novel production method suitable for industrial production of a 3, 3-dimethyl-3, 4-dihydro-1H-quinoxaline-2-one derivative; and a synthetic intermediate therefor. Provided is a production method is for a compound indicated by formula (1) or a salt thereof, said production method including: a step in which a compound indicated by formula (2) or a salt thereof is reacted with a nitrating agent and a compound indicated by formula (3) or a salt thereof is obtained; and a step in which the compound indicated by formula (3) or a salt thereof is reduced and a compound indicated by formula (1) or a salt thereof is obtained. (Each symbol in the formulas (1, 2, 3) is the same as in the definitions in claim 1.)