This method of producing 4-(((6S,9S)-1-(benzylcarbamoyl)-2,9-dimethyl-4,7-dioxo-8-(quino line-8-ylmethyl) octahydro-1H-pyrazino[2,1-c][1,2,4]triazine-6-yl)methyl) phenyl dihydrogen phosphate involves a step for adding a reaction solution (1) comprising (6S,9S)-N-benzyl-6-(4-hydroxybenzyl)-2,9-dimethyl-4,7-dioxo-8-( quinoline-8-ylmethyl) octahydro-1H-pyrazino[2,1-c][1,2,4]triazine-1-carboxamide, triethylamine and a solvent to a reaction solution (2) comprising a phosphorylating agent and a solvent.Un método para producir dihidrógeno fosfato de 4-(((6S,9S)-1-(bencilcarbamoil)-2,9-dimetil-4,7-dioxo-8-(quinolin -8-ilmetil)octahidro-1H-pirazino[2,1-c][1,2,4]triazin-6-il)metil) fenil, que incluye un paso de añadir una mezcla de reacción 1 que contiene(6S,9S)-N- bencil-6-(4-hidroxibencil)-2,9-dimetil-4,7-diox o-8-(quinolin-8-ilmetil)octahidro-1H-pirazino[2,1-c][1,2,4]triazi na-1-carboxamída, trietilamina y un solvente a una mezcla de reacción 2 que contiene un agente fosforilante y un solvente.
