(2-ethyl-10b-hydroxy-5-isopropyl-3,6-dioxo-octahydro-oxazolo[3,2-a]pyrrolo[2,1-c]pyrazin-2-yl)-carbamic acid benzyl ester 、
氟磺酸甲酯 生成 benzyl N-[(1S,2S,4R,7S)-4-ethyl-2-hydroxy-5,8-dioxo-7-propan-2-yl-3-oxa-6,9-diazatricyclo[7.3.0.02,6]dodecan-4-yl]-N-methylcarbamate