(+/-)-9-bromo-5-[p-tert-butoxycarbonylaminomethyl-o-(methoxycarbonyl)phenylcarbamoylmethyl]-6,7-dihydro-1H, 5H-pyrido[1,2,3-de]quinoxaline-2,3-dione 以89%的产率得到(+/-)-9-bromo-5-[p-aminomethyl-o-(methoxycarbonyl)phenylcarbamoylmethyl]-6,7-dihydro-1H, 5H-pyrido[1,2,3-de]quinoxaline-2,3-dione