4-((R)-1-{5-[6-(benzotriazol-1-yloxy)pyridazin-3-yl]-[1,2,4]oxadiazol-3-yl}ethoxy)piperidine-1-carboxylic acid isopropyl ester 、
[(3R,4S)-4-(2,5-difluorophenyl)pyrrolidin-3-yl]carbamic acid tert-butyl ester 在
乙酸乙酯 、 Brine 、
magnesium sulfate 作用下,
以
二甲基亚砜 、
水 为溶剂,
反应 1.0h,
以to afford the intermediate product 4-[(R)-1-(5-{6-[(3R,4S)-3-tert-butoxycarbonylamino-4-(2,5-difluorophenyl)pyrrolidin-1-yl]pyridazin-3-yl}-[1,2,4]oxadiazol-3-yl)ethoxy]piperidine-1-carboxylic acid isopropyl ester的产率得到4-[(R)-1-(5-{6-[(3R,4S)-3-tert-butoxycarbonylamino-4-(2,5-difluorophenyl)pyrrolidin-1-yl]pyridazin-3-yl}-[1,2,4]oxadiazol-3-yl)ethoxy]piperidine-1-carboxylic acid isopropyl ester p-toluenesulfonate