Taking Rhein as the lead compound, ten esters of rhein were synthesized by esterification. For synthesis of smaller steric hindrance alcohols, SOCl₂ was used as a catalyst to synthesize methyl, ethyl and butyl esters. For lager steric hindrance alcohols, dicyclohexyl carbodiimide (DCC) was used as dehydrating agent, and 4-dimethylaminopyridine (DMAP) was used as the catalyst to synthesize isopropyl, isobutyl, tertbutyl, isoamyl, benzyl, 2-phenyl ethyl, 2-chloroethyl esters. Structural characterization of the target compounds were done using melting point, ¹H NMR, ¹³C NMR and HRMS. Five out of the 10 compounds were new. All the compounds were evaluated for antitumor activities in vitro against Hela human cervical carcinoma cell lines. Study found that all the ten compounds showed differences in their growth inhibitory effect on tumor cells. Compound with benzyl groups improved the antitumor activity. Results showed that compound 3b exhibited maximum activity against Hela cell lines at 100 μg mL^–1 (IC₅₀ value) with an inhibition rate of 70%, while the derivative 3i showed the lowest inhibitory activity (IC₅₀ <64.3 μg mL^–1).

中文翻译：

---

大黄酸的酯衍生物的合成及其对宫颈癌细胞的体外抗肿瘤活性

以大黄酸为先导化合物，通过酯化反应合成了十个大黄酸酯。为了合成较小的空间位阻醇，使用SOCl ₂作为催化剂来合成甲基，乙基和丁酯。对于较大的位阻醇，将二环己基碳二亚胺（DCC）用作脱水剂，并将4-二甲基氨基吡啶（DMAP）用作催化剂，以合成异丙基，异丁基，叔丁基，异戊基，苄基，2-苯基乙基，2-氯乙基酯。使用熔点，¹ H NMR，¹³ C NMR和HRMS对目标化合物进行结构表征。10种化合物中有5种是新化合物。评估了所有化合物的体外抗肿瘤活性对抗Hela人宫颈癌细胞系。研究发现，所有十种化合物对肿瘤细胞的生长抑制作用均存在差异。具有苄基的化合物改善了抗肿瘤活性。结果表明，化合物3b在100μgmL ^–1（IC ₅₀值）下对Hela细胞系表现出最大的活性，抑制率为70％，而衍生物3i的抑制活性最低（IC ₅₀ <64.3μgmL ^–1）。 。