Organocatalytic asymmetric vinylogous 1,4-addition of α,α-Dicyanoolefins to chalcones under a bio-based reaction media: Discovery of new Michael adducts with antiplasmodial activity

One-pot synthesis of γ-lactams from ketoaziridines

The remarkable biological activities of γ-lactams have stimulated the search for efficient synthetic methods to achieve these scaffolds. In this work, we have developed a simple one-pot diastereoselective synthesis of new γ-lactams from ketoaziridines with moderate to good yields via the Horner-Wadsworth-Emmons reaction, followed by an intramolecular ester-aziridine cyclization and its opening in situ. Preliminary efforts towards an enantioselective version of this method are also reported.

Recent Advances in Greener Asymmetric Organocatalysis Using Bio-Based Solvents

Efficient synthetic methods that avoid the extensive use of hazardous reagents and solvents, as well as harsh reaction conditions, have become paramount in the field of organic synthesis. Organocatalysis is notably one of the best tools in building chemical bonds between carbons and carbon-heteroatoms; however, most examples still employ toxic volatile organic solvents. Although a portfolio of greener solvents is now commercially available, only ethyl alcohol, ethyl acetate, 2-methyltetrahydrofuran, supercritical carbon dioxide, ethyl lactate, and diethyl carbonate have been explored with chiral organocatalysts. In this review, the application of these bio-based solvents in asymmetric organocatalytic methods reported in the last decade is discussed, highlighting the proposed mechanism pathway for the transformations.

Application of Biobased Solvents in Asymmetric Catalysis

The necessity of more sustainable conditions that follow the twelve principles of Green Chemistry have pushed researchers to the development of novel reagents, catalysts and solvents for greener asymmetric methodologies. Solvents are in general a fundamental part for developing organic processes, as well as for the separation and purification of the reaction products. By this reason, in the last years, the application of the so-called green solvents has emerged as a useful alternative to the classical organic solvents. These solvents must present some properties, such as a low vapor pressure and toxicity, high boiling point and biodegradability, and must be obtained from renewable sources. In the present revision, the recent application of these biobased solvents in the synthesis of optically active compounds employing different catalytic methodologies, including biocatalysis, organocatalysis and metal catalysis, will be analyzed to provide a novel tool for carrying out more ecofriendly organic processes.

Asymmetric organocatalysis: an enabling technology for medicinal chemistry

The efficacy and synthetic versatility of asymmetric organocatalysis have contributed enormously to the field of organic synthesis since the early 2000s. As asymmetric organocatalytic methods mature, they have extended beyond the academia and undergone scale-up for the production of chiral drugs, natural products, and enantiomerically enriched bioactive molecules. This review provides a comprehensive overview of the applications of asymmetric organocatalysis in medicinal chemistry. A general picture of asymmetric organocatalytic strategies in medicinal chemistry is firstly presented, and the specific applications of these strategies in pharmaceutical synthesis are systematically described, with a focus on the preparation of antiviral, anticancer, neuroprotective, cardiovascular, antibacterial, and antiparasitic agents, as well as several miscellaneous bioactive agents. The review concludes with a discussion of the challenges, limitations and future prospects for organocatalytic asymmetric synthesis of medicinally valuable compounds.

QSAR studies on benzothiophene derivatives as Plasmodium falciparum N-myristoyltransferase inhibitors: Molecular insights into affinity and selectivity

Malaria is an infectious disease caused by protozoan parasites of the genus Plasmodium and transmitted by Anopheles spp. mosquitos. Due to the emerging resistance to currently available drugs, great efforts must be invested in discovering new molecular targets and drugs. N-myristoyltransferase (NMT) is an essential enzyme to parasites and has been validated as a chemically tractable target for the discovery of new drug candidates against malaria. In this work, 2D and 3D quantitative structure-activity relationship (QSAR) studies were conducted on a series of benzothiophene derivatives as P. falciparum NMT (PfNMT) and human NMT (HsNMT) inhibitors to shed light on the molecular requirements for inhibitor affinity and selectivity. A combination of Quantitative Structure-activity Relationship (QSAR) methods, including the hologram quantitative structure-activity relationship (HQSAR), comparative molecular field analysis (CoMFA), and comparative molecular similarity index analysis (CoMSIA) models, were used, and the impacts of the molecular alignment strategies (maximum common substructure and flexible ligand alignment) and atomic partial charge methods (Gasteiger-Hückel, MMFF94, AM1-BCC, CHELPG, and Mulliken) on the quality and reliability of the models were assessed. The best models exhibited internal consistency and could reasonably predict the inhibitory activity against both PfNMT (HQSAR: q² /r² /r² _pred = 0.83/0.98/0.81; CoMFA: q² /r² /r² _pred = 0.78/0.97/0.86; CoMSIA: q² /r² /r² _pred = 0.74/0.95/0.82) and HsNMT (HQSAR: q² /r² /r² _pred = 0.79/0.93/0.74; CoMFA: q² /r² /r² _pred = 0.82/0.98/0.60; CoMSIA: q² /r² /r² _pred = 0.62/0.95/0.56). The results enabled the identification of the polar interactions (electrostatic and hydrogen-bonding properties) as the major molecular features that affected the inhibitory activity and selectivity. These findings should be useful for the design of PfNMT inhibitors with high affinities and selectivities as antimalarial lead candidates.