3-O,3-O'-ditert-butyl 4-O-ethyl 7,8,9-trifluoro-5-hydroxy-1-methyl-2,3a-dihydropyrazolo[1,5-a]quinoline-3,3,4-tricarboxylate 在
caesium carbonate 作用下,
以
二甲基亚砜 为溶剂,
反应 3.5h,
以49%的产率得到Ethyl 3,3-bis(tert-butoxycarbonyl)-4,5-difluoro-2,3-dihydro-1-methyl-7-oxo-1H,7H-pyrido<3,2,1-i,j>cinnoline-8-carboxylate