First total synthesis of caerulomycin K: a case study on selective, multiple C-H functionalizations of pyridines

Caerulomycins, natural alkaloids with antimicrobial properties, have been previously synthesized starting with highly pre-functionalized building blocks or requiring many functional group manipulations. In this work, we report the first total synthesis of caerulomycin K, a diversely trifunctionalized pyridine readily assembled in three steps exploiting the recent advancements in the C-H activation of N-heterocycles.

Recent Advances in SARS-CoV-2 Main Protease Inhibitors: From Nirmatrelvir to Future Perspectives

The main protease (Mpro) plays a pivotal role in the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is considered a highly conserved viral target. Disruption of the catalytic activity of Mpro produces a detrimental effect on the course of the infection, making this target one of the most attractive for the treatment of COVID-19. The current success of the SARS-CoV-2 Mpro inhibitor Nirmatrelvir, the first oral drug for the treatment of severe forms of COVID-19, has further focused the attention of researchers on this important viral target, making the search for new Mpro inhibitors a thriving and exciting field for the development of antiviral drugs active against SARS-CoV-2 and related coronaviruses.

Synthesis of SARS-CoV-2 Mpro inhibitors bearing a cinnamic ester warhead with in vitro activity against human coronaviruses

COVID-19 now ranks among the most devastating global pandemics in history. The causative virus, SARS-CoV-2, is a new human coronavirus (hCoV) that spreads among humans and animals. Great efforts have been made to develop therapeutic agents to treat COVID-19, and among the available viral molecular targets, the cysteine protease SARS-CoV-2 M^pro is considered the most appealing one due to its essential role in viral replication. However, the inhibition of M^pro activity is an interesting challenge and several small molecules and peptidomimetics have been synthesized for this purpose. In this work, the Michael acceptor cinnamic ester was employed as an electrophilic warhead for the covalent inhibition of M^pro by endowing some peptidomimetic derivatives with such a functionality. Among the synthesized compounds, the indole-based inhibitors 17 and 18 efficiently impaired the in vitro replication of beta hCoV-OC-43 in the low micromolar range (EC₅₀ = 9.14 μM and 10.1 μM, respectively). Moreover, the carbamate derivative 12 showed an antiviral activity of note (EC₅₀ = 5.27 μM) against another hCoV, namely hCoV-229E, thus suggesting the potential applicability of such cinnamic pseudopeptides also against human alpha CoVs. Taken together, these results support the feasibility of considering the cinnamic framework for the development of new M^pro inhibitors endowed with antiviral activity against human coronaviruses.

Modulation of platelet membrane function via exogenous lipid moiety exposure alters platelet responsiveness to shear

Shear-induced platelet activation may cause life-threatening thrombosis, particularly in patients with mechanical support devices or coronary atherosclerosis. The majority of present anti-platelet agents target or interfere with biochemical, rather than physical mechanisms of platelet activation. Less data and understanding exists with regard to pharmacologic modulation of shear-mediated platelet activation. In this work, we hypothesized that modulating cell membrane properties, via alteration of membrane composition through addition of exogenous lipid moieties, would alter platelet responsiveness to shear. Here we tested fatty acids, lecithin and cholesterol as additive lipid compounds. We demonstrated that incorporation of fatty acids (DHA/EPA) or lecithin into the platelet membrane triggered enhanced sensitivity of platelets to shear-mediated activation. On the other hand, cholesterol incorporation provides significant protection, limiting the effect of shear on platelet activation. These findings provide valuable insight for the development of therapeutic strategies that can modulate shear-mediated platelet activation.