Stereoselective Synthesis and Biological Evaluation of ent -Asperolide C and its Analogues

Synthetic Modifications of Andrographolide Targeting New Potential Anticancer Drug Candidates: A Comprehensive Overview

This review collects the synthetic modifications performed on andrographolide, a natural molecule derived from Andrographis paniculata, for oncology applications. Various pharmacomodulations were carried out, and the products were tested on different cancer cell lines. The impact of these modifications was analyzed with the aim of mapping the positions essential for activity to facilitate future research in this field. However, this study makes it clear that, in addition to structural modifications of the molecule, which can result in varying degrees of effectiveness in targeting interactions, the lipophilic capacity of the structures obtained through hemisynthesis is of significant importance.

A new δ-valerolactone produced by marine Streptomyces sp. YIM 13591

A new δ-valerolactone compound, named 8-hydroxy invictolide 2 (1), a new natural product 4-hydroxy-3,5-dimethyl-6-(pentan-2-yl) tetrahydro-2H-pyran-2-one (2) together with four known compounds cyclo (L-Pro-L-Tyr) (3), cyclo (D-Pro-L-Tyr) (4), acetyltryptophan methyl ester (5), 2-aminobenzoic acid (6) were isolated from marine Streptomyces sp. YIM 13591. Their structures were elucidated by NMR spectroscopic data, HRESIMS and specific rotation, and the absolute configurations of the stereo centre in lactone ring 1 and 2 were further confirmed by electronic circular dichroism (ECD) calculation. The antimicrobial effects of these compounds were evaluated by the paper diffusion method.

Synthesis of ent-Cleistanthane Diterpenoid Spruceanol: Construction of an Aromatic C Ring via Lewis Acid-Controlled Regioselective Diels-Alder Cycloaddition

The first synthesis of ent-cleistanthane-type diterpenoid spruceanol with significant anticancer activity is described. A chiral pool approach was employed with a linear sequence of 13 steps beginning from readily available and inexpensive andrographolide. The approach features the construction of an aromatic ring with hydroxyl and methyl groups at C-12 and C-13 of the target compound, respectively, via Lewis acid-controlled regioselective Diels-Alder cycloaddition and the regioselective removal of the primary hydroxyl group of the Diels-Alder adduct.

Synthesis of γ-Lactones Utilizing Ketoacids and Trimethylsulfoxonium Iodide

The Johnson-Corey-Chaykovsky epoxidation is one of the oldest methods for the synthesis of terminal epoxides from carbonyl compounds. Herein we present a simplified extension of the Johnson-Corey-Chaykovsky epoxidation, where ketoacids are employed as the substrates and commercially available trimethylsulfoxonium iodide is employed as the carbon-atom homologating reagent. A variety of lactones are produced in a single step in synthetically useful yields.