Claim 1: a method of production of 1 - (4 - [1 - (2,6 - difluorobencil) - 5 - (dimetilaminometil - 3 - 6 - metoxipiridazin - 3 - yl) - 2.4 - cyclohexanecarboxylic tetrahidrotieno - 1,2,3,4 - [2,3-d] pyrimidine 6 il] - phenyl - 3 - or a metoxiurea} its Salts, characterized in that it comprises reacting 6 - (4-aminophenyl) - 1 - (2,6 - difluoro Benzyl) - 5 - (dimetilaminometil - 3 - 6 - metoxipiridazin - 3 - il) thieno [2,3-d] pyrimidine 2,4 (1H, 3H) - dione or its Salt1.1 - carbonildiimidazol or one of its Salts and metoxiamina or one of its Salts.Reivindicación 1: Un método de producción de 1-{4-[1-(2,6-difluorobencil)-5-dimetilaminometil-3-(6-metoxipiridazin-3-il)-2,4-dioxo-1,2,3,4-tetrahidrotieno[2,3-d]pirimidin-6-il]fenil}-3-metoxiurea o una de sus sales, caracterizado porque comprende hacer reaccionar 6-(4-aminofenil)-1-(2,6-difluorobencil)-5-dimetilaminometil-3-(6-metoxipiridazin-3-il)tieno[2,3-d]pirimidin-2,4(1H,3H)-diona o su sal, 1,1-carbonildiimidazol o una de sus sales y metoxiamina o una de sus sales.
