3-(3-{2-[4-(2-Chloro-phenyl)-piperazin-1-yl]-ethyl}-2,4-dioxo-3,4-dihydro-2H-thieno[3,4-d]pyrimidin-1-yl)-propionic acid 在
甲烷磺酸 、 phosphorus pentoxide 作用下,
以55%的产率得到4-{2-[4-(2-Chloro-phenyl)-piperazin-1-yl]-ethyl}-6,7-dihydro-1-thia-4,5a-diaza-acenaphthylene-3,5,8-trione