(6R,7R)-7-(1,3-Dioxo-1,3-dihydro-isoindol-2-yl)-8-oxo-3-(tetrahydro-pyran-2-yloxymethyl)-4,5-dithia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid methyl ester 在
4-甲基苯磺酸吡啶 作用下,
以
乙醇 为溶剂,
反应 1.0h,
生成
(1R,6aS)-1-(1,3-Dioxo-1,3-dihydro-isoindol-2-yl)-1,6a-dihydro-5H-4-oxa-6-thia-2a-aza-cyclobuta[a]pentalene-2,3-dione