Semisynthesis of triptolide analogues: Effect of B-ring substituents on cytotoxic activities

Chlotrichenes A and B, Two Lindenane Sesquiterpene Dimers with Highly Fused Carbon Skeletons from Chloranthus holostegius

“…The sequential olefination of allylic position at C5/6, stereoselective epoxidation of the active Δ 8,9 olefinic bond, epoxide cleavage, and lactone opening of i generate the universal intermediate v with the required conjugated Δ 15(4),5(6) system. ,, An endo -selective [4 + 2] cycloaddition of two molecules of v between Δ 15(4),5(6) and Δ 15′(4′) produces the spiro-fused lindenane homodimer framework of 2 . Further, the terminal Δ 5′,6′ of unsaturated ester of 2 is subjected to another epoxidation to give epoxide vi . The possibly allylic dehydrogenation of H-6 ( vii ) generates the evolving carbanion ( viii ).…”

Synthesis of celastrol derivatives as potential non‐nucleoside hepatitis B virus inhibitors

“…Taken together, celastrol should be a promising bioactive natural product for new drug discovery. However, unlike its relative triptolide, lots of total synthesis and structural modifications have conducted in the past two decades (Chen, Zhou, & Li, 2012; Hou, Liu, & Xu, 2019b; Kaloun et al., 2016; Liu et al., 2018; Ning et al., 2018; Patil et al., 2015; Wang et al., 2017; Xu, Chen, Tang, Feng, & Li, 2014; Xu et al., 2017; Xu & Liu, 2019; Xu, Tang, Feng, & Li, 2014a, 2014b; Xu, Tang, Yang, Feng, & Li, 2014; Zhang, Xiao, & Xu, 2019; Zhou, Yang, Ding, Li, & Miao, 2012), and some triptolide derivatives have already entered clinic for the treatment of challenging cancer and/or rheumatoid arthritis (RA) (Carter et al., 2012; Pao et al., 2019; Patil et al., 2012; Wang, Xu, Fu, Li, & Lou, 2012; Zhou et al., 2005). So far, there is only one total synthesis (Camelio, Johnson, & Siegel, 2015) and several chemical modifications of celastrol have been reported (Figueiredo, Salvador, Cortés, & Cascante, 2017a; Jiang et al., 2016; Kyriakou et al., 2018; Li et al., 2015, 2018; Pang, Luo, Liu, Wu, & Wang, 2018; Shan et al., 2017; Tang, Huang, Pan, Zhang, & Lu, 2015; Zhang, Zhang, Piao, & Quan, 2018; Zhu et al., 2017), which are largely focused on its anti‐cancer activity.…”

Click chemistry‐based synthesis and cytotoxic activity evaluation of 4α‐triazole acetate podophyllotoxin derivatives

“…Considering the benefits mentioned above and in continuation of our interest in searching for the anticancer and antimicrobial pharmacological effects of derivatives of NPs (Hou et al., , ; Xu, Chen, Tang, Feng, & Li, ; Xu, Tang, Feng, & Li, 2014c; Xu et al., , ), we therefore conducted a modification via conjugating PPT and 1,2,3‐triazole pharmacophore into one molecule to generate 4α‐triazole acetate PPT ester hybrid through CuAAC for anticancer activity evaluation. Herein, we described the synthesis of these derivatives and the evaluation of their in vitro cytotoxic activities, selectivity over non‐cancer cell lines, potential against drug‐resistance tumor cells, and preliminary elucidation of their underlying mechanistic of cytotoxicity.…”