4-(2,4-dioxo-2,3,4,5,7,8-hexahydropyrano[3,4-e][1,3]oxazin-8-yl)benzonitrile 、
ammonium hydroxide 以to give 4-(2,4-dioxo-2,3,4,5,7,8-hexahydro-1H-pyrano[4,3-d]pyrimidin-8-yl)benzonitrile (Intermediate AA(4))的产率得到4-(2,4-dioxo-2,3,4,5,7,8-hexahydro-1H-pyrano[4,3-d]pyrimidin-8-yl)benzonitrile