C-terminal constrained phenylalanine as a pharmacophoric unit in peptide-based proteasome inhibitors

Chemical Patterns of Proteasome Inhibitors: Lessons Learned from Two Decades of Drug Design

Drug discovery now faces a new challenge, where the availability of experimental data is no longer the limiting step, and instead, making sense of the data has gained a new level of importance, propelled by the extensive incorporation of cheminformatics and bioinformatics methodologies into the drug discovery and development pipeline. These enable, for example, the inference of structure-activity relationships that can be useful in the discovery of new drug candidates. One of the therapeutic applications that could benefit from this type of data mining is proteasome inhibition, given that multiple compounds have been designed and tested for the last 20 years, and this collection of data is yet to be subjected to such type of assessment. This study presents a retrospective overview of two decades of proteasome inhibitors development (680 compounds), in order to gather what could be learned from them and apply this knowledge to any future drug discovery on this subject. Our analysis focused on how different chemical descriptors coupled with statistical tools can be used to extract interesting patterns of activity. Multiple instances of the structure-activity relationship were observed in this dataset, either for isolated molecular descriptors (e.g., molecular refractivity and topological polar surface area) as well as scaffold similarity or chemical space overlap. Building a decision tree allowed the identification of two meaningful decision rules that describe the chemical parameters associated with high activity. Additionally, a characterization of the prevalence of key functional groups gives insight into global patterns followed in drug discovery projects, and highlights some systematically underexplored parts of the chemical space. The various chemical patterns identified provided useful insight that can be applied in future drug discovery projects, and give an overview of what has been done so far.

An innovation for development of Erlenmeyer–Plöchl reaction and synthesis of AT-130 analogous: a new application of continuous-flow method

The first micro-flow Erlenmeyer–Plöchl azlactone reaction and synthesis of N-benzoylglycine carbamide were established.

Alpha,beta-unsaturated N-acylpyrrole peptidyl derivatives: new proteasome inhibitors

Because of the encouraging results obtained using vinyl ester derivatives, we synthesized and tested a novel series of peptide-based proteasome inhibitors bearing a new pharmacophore unit at the C-terminal. N-Acylpyrrole moiety is a potential substrate for Michael addition by catalytic threonine. Several analogues have demonstrated a selective inhibition of the multicatalytic complex beta1 subunits, the capacity to permeate cellular membrane, and good pharmacokinetics properties.

N-terminal-prolonged vinyl ester-based peptides as selective proteasome beta1 subunit inhibitors

The synthesis and biological properties of vinyl ester peptide-based molecules bearing linear N-terminal amino acids are reported. Compounds were tested in vitro for their capacity to inhibit the chymotryptic-, tryptic-like, and post-acidic activities of the proteasome. Some analogues showed selective inhibition of post-acidic (PGPH) activity, which is attributed to the beta1 subunit. Interestingly, active compounds demonstrated higher inhibitory activity toward 'standard' proteasomes than toward immunoproteasomes. The inhibitory potency was found to be related to the amino acidic sequence and to the length of the N-terminal residues. The new inhibitors demonstrated resistance to plasmatic proteases and a good capacity to permeate the cell membrane.