Synthesis of Cycloheptatriene-Containing Azetidine Lactones

A review of the synthetic strategies toward the antiviral drug tecovirimat

This review provides a comprehensive analysis of synthetic routes for tecovirimat, an antiviral drug used to treat orthopoxvirus infections, including monkeypox and smallpox. We focus on the scale-up synthesis of key intermediates, including cycloheptatriene, as documented in the published literature and patent records. The review highlights the efficiency, yield, and purity of these approaches, as well as the minimization of genotoxic and in-process impurities. Furthermore, we critically evaluate the recently reported optimized industrial-scale synthesis process, highlighting its advantages and limitations, and identifying avenues for further improvement. By obtaining insights from the published literature and patent records, this review elucidates the current state of knowledge regarding key synthesis parameters influencing tecovirimat production and emphasizes the critical importance of optimizing synthesis techniques to achieve remarkable improvements in safety and environmental impact. This review serves as a valuable resource for researchers and industry professionals in the field of R&D and production of APIs, particularly in expediting the safe and efficient industrial production of tecovirimat.

Molecular complexity as a driving force for the advancement of organic synthesis

The generation of molecular complexity is a primary goal in the field of synthetic chemistry. In the context of retrosynthetic analysis, the concept of molecular complexity is central to identifying productive disconnections and the development of efficient total syntheses. However, this field-defining concept is frequently invoked on an intuitive basis without precise definition or appreciation of its subtleties. Methods for quantifying molecular complexity could prove useful for characterizing the state of synthesis in a more rigorous, reliable and reproducible fashion. As a first step to evaluating the importance of these methods to the state of the field, here we present our perspective on the development of molecular complexity quantification and its implications for chemical synthesis. The extension and application of these methods beyond computer-aided synthesis planning and medicinal chemistry to the traditional practice of 'complex molecule' synthesis could have the potential to unearth new opportunities and more efficient approaches for synthesis.

Twisted Intramolecular Charge-Transfer State Addition to Electron-Poor Olefins

When electron-rich arylpyrrolinium salts are irradiated with ultraviolet light in the presence of Michael acceptors, the pyrrolinyl and aryl fragments add to the activated and polarized double bond in a regioselective manner, forming two C-C bonds and fragmenting the substrate. In this paper, we present a model for this intriguing reaction, supported by spectroscopy and computational analyses, and provide evidence for rectifying previously misassigned structures. We postulate that the photochemical reaction is inefficient because the reaction between the twisted intramolecular charge-transfer state and the olefin competes with fluorescence from this state upon photon absorption. We also discuss the practical advantages of performing this photochemical reaction in a continuous flow setup. Additionally, we explore several subsequent reactions that allow us to further modify the products of the photochemical step, ultimately leading to the creation of new chemical structures.

Spacial Score─A Comprehensive Topological Indicator for Small-Molecule Complexity

The fraction of sp3-hybridized carbons (Fsp3) and the fraction of stereogenic carbons (FCstereo) are two widely employed scores of molecular complexity with strong links to biologically relevant features. However, they do not comprehensively express molecular topology, and they often do not match the chemical intuition of complexity. We propose the spacial score (SPS) as an empirical scoring system that builds upon the principle underlying Fsp3 and FCstereo and expresses the spacial complexity of a compound in a uniform manner on a highly granular scale. The size-normalized SPS (nSPS) can differentiate distributions of natural products and synthetic compounds and is applicable in the analysis of biological activity data. Analysis of the ChEMBL database revealed general trends of increasing selectivity and potency with increasing nSPS. SPS can also be used advantageously in planning and analysis of synthesis programs for direct comparison of chemical transformations and intermediates in reaction sequences.

Visible-Light-Mediated Energy Transfer Enables the Synthesis of β-Lactams via Intramolecular Hydrogen Atom Transfer

The synthesis of 2-azetidinones (β-lactams) from simple acrylamide starting materials by visible-light-mediated energy transfer catalysis is reported. The reaction features a C(sp3 )-H functionalization via a variation of the Norrish-Yang photocyclization involving a carbon-to-carbon 1,5-hydrogen atom transfer (supported by deuterium labelling and DFT calculations) and can be used for the construction of a diverse range of β-lactam products.