2.2　Materials

Cordycepin(98% purify)was purchased from Sigma(USA).Adenosine，adenine，and glycol dimethyl acrylate were purchased from Shanghai Husker Chemical(Shanghai，China).Azobisisobutyronitrile was purchased from Shanghai No.4 Reagent& H.V Chemical Co.(Shanghai，China).Tetrahydrofuran and alphamethylacrylic acid were purchased from China National Pharmaceutical Group Industry Corporation(Shanghai，China).The chemicals were of analytical reagent grade.Methanol and acetonitrile of chromatographic purity were obtained from China National Pharmaceutical Group Industry Corporation(Shanghai，China).Ultrapure water was prepared by a UP-90 purification system(Nanjing，China).In order to remove the polymerization inhibitor，glycol dimethyl acrylate and alpha-methylacrylic acid were purified by vacuum distillation before use.Azobisisobutyronitrile was recrystallized with methanol and dried under reduced pressure before use.(https://www.daowen.com)