Drimane and coloratane sesquiterpenoids are present in several plants, microorganisms, and marine life. Because of their cytotoxic activity, these sesquiterpenoids have received increasing attention as a source for new anticancer drugs and pharmacophores. Natural drimanes and coloratanes, as well as their semi-synthetic derivatives, showed promising results against cancer cell lines with in vitro activities in the low micro- and nanomolar range. Despite their high potential as novel anticancer agents, the mode of action and structure–activity relationships of drimanes and coloratanes have not been completely enlightened nor systematically reviewed. Our review aims to give an overview of known structures and derivatizations of this class of sesquiterpenoids, as well as their activity against cancer cells and potential modes-of-action. The cytotoxic activities of about 40 natural and 25 semi-synthetic drimanes and coloratanes are discussed. In addition to that, we give a summary about the clinical significance of drimane and coloratane sesquiterpenoids.

Artemisinin-based combination therapies (ACTs) are the gold standard for the treatment of malaria, but the efficacy is threatened by the development of parasite resistance. Histone deacetylase inhibitors (HDACis) are an emerging new class of potential antiplasmodial drugs. In this work, we present the design, synthesis, and biological evaluation of a mini library of dihydroartemisinin–HDACi hybrid molecules. The screening of the hybrid molecules for their activity against selected human HDAC isoforms, asexual blood stage P. falciparum parasites, and a panel of leukemia cell lines delivered important structure–activity relationships. All synthesized compounds demonstrated potent activity against the 3D7 and Dd2 line of P. falciparum with IC₅₀ values in the single-digit nanomolar range. Furthermore, the hybrid (α)-7c displayed improved activity against artemisinin-resistant parasites compared to dihydroartemisinin. The screening of the compounds against five cell lines from different leukemia entities revealed that all hydroxamate-based hybrids (7a–e) and the ortho-aminoanilide 8 exceeded the antiproliferative activity of dihydroartemisinin in four out of five cell lines. Taken together, this series of hybrid molecules represents an excellent starting point toward the development of antimalarial and antileukemia drug leads.

This work evaluates the direct etherification of bio-sourced isobutylene with ethanol forming fully renewable ethyl tert-butyl ether (ETBE). Challenge was the use of the fermentative produced substrate in a solvent-free catalysis using the acidic ion exchanger Amberlyst-15. CO₂ impurities have a significant influence on the liquid phase process. The conversion at a ratio that is based on molarities of isobutylene to ethanol of 1:0.9 results in yields up to 97 mol% ETBE. Purities up to 99 wt.% could be achieved by subsequent water extraction in order to ensure qualities for technical application as high performance fuel additive.

Several studies have linked chemerin/chemokine-like receptor 1 (CMKLR1) to inflammation, leukocyte recruitment, and obesity. Reduced cellular activation may reduce inflammation in adipose tissues. High-throughput screening identified a novel antagonist (VU0514009), which was optimized to compound 16 as a full and competitive antagonist (IC₅₀ = 37 μM). Mutagenesis studies elucidated relevant interactions of compound 16 at CMKLR1 residues Y6.51 and L7.35 as well as F7.31, S7.32, and T7.39 forming the binding pocket. Based on active CMKLR1/chemerin-9 structures and the inactive AlphaFold model, in silico docking was performed in the inactive model, with compound 16 most likely binding orthosterically. Considering the sequence similarity of CMKLR1 and GPR1, compound 16 was docked to GPR1, indicating a similar binding. At GPR1, compound 16 showed a slightly lower effect on chemerin-9-mediated arrestin recruitment and internalization.