(E)-but-2-enedioic acid diphenyl ester 、
1,3,9-trimethyl-7-(2,3,5,6-tetramethylphenacyl)xanthinium toluene-p-sulphonate 在
三乙胺 作用下,
以
乙腈 为溶剂,
以81.2%的产率得到(6S,7S,8S,8aR)-1,3,9-Trimethyl-2,4-dioxo-6-(2,3,5,6-tetramethyl-benzoyl)-2,3,4,6,7,8,8a,9-octahydro-1H-pyrrolo[2,1-f]purine-7,8-dicarboxylic acid diphenyl ester