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 Mpro is considered the most appealing one due to its essential role in viral replication. However, the inhibition of Mpro 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 Mpro 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 Mpro inhibitors endowed with antiviral activity against human coronaviruses

Prompt and Long-Lived Anti-Kasha Emission from Organic Dyes

Anti-Kasha behavior has been the subject of intense debate in the last few years, as demonstrated by the high number of papers appearing in the literature on this topic, dealing with both mechanistic and applicative aspects of this phenomenon. Examples of anomalous emitters reported in the last 10 years are collected in the present review, which is focused on strictly anti-Kasha organic molecules displaying radiative deactivation from Sn and/or Tn, with n greater than 1

Synthesis of potent and selective HDAC6 inhibitors led to unexpected opening of a quinazoline ring

Histone deacetylase (HDAC) inhibitors are highly involved in the regulation of many pharmacological responses, which results in anti-inflammatory and anti-cancer effects. In the present work, chemoinformatic analyses were performed to obtain two potent and selective aminotriazoloquinazoline-based HDAC6 inhibitors. We unexpectedly obtained an aminotriazole from a water-driven ring opening of the triazoloquinazoline scaffold. Both compounds were evaluated as HDAC6 inhibitors, resulting in subnanomolar inhibitory activity and high selectivity with respect to class I HDAC1 and HDAC8. Importantly, the compounds were about 3- and 15-fold more potent compared to the reference compound trichostatin A. Additionally, the predicted binding modes were investigated with docking. Considering that the aminotriazole scaffold has never been embedded into the chemical structure of HDAC6 inhibitors, the present study suggests that both the aminotriazoloquinazoline and aminotriazole classes of compounds could be excellent starting points for further optimization of potential anticancer compounds, introducing such novel groups into a relevant and new area of investigation