Novel nonpeptidic inhibitors of HIV-1 protease obtained via a new multicomponent chemistry strategy

Two decades of recent advances of Passerini reactions: synthetic and potential pharmaceutical applications

This perspective describes the applications of Passerini reactions in the last two decades from 2000 to 2021 in pharmaceutical applications and synthesis of peptides, natural products, macrocycles, dendrimers, and versatile types of heterocycles.

The 100 facets of the Passerini reaction

This perspective aims at celebrating the 100th anniversary of the discovery of the Passerini three component reaction. After being nearly neglected for many years, now this reaction has become quite popular, thanks to the achievements of the last 30 years, which have revealed several chances of exploitation in organic synthesis. Though not being comprehensive, this review means to show the various ways that have been used in order to expand the utility of the Passerini reaction. Post-MCR transformations to give heterocycles or peptidomimetics, variants through single component replacement, stereochemical issues, and applications in total syntheses will be especially covered.

Multicomponent reactions in the synthesis of antiviral compounds

BACKGROUND

Multicomponent reactions are one-pot processes for the synthesis of highly functionalized hetero-cyclic and hetero-acyclic compounds, often endowed with biological activity.

OBJECTIVE

Multicomponent reactions are considered green processes with high atom economy. In addition, they present advantages compared to the classic synthetic methods such as high efficiency and low wastes production.

METHOD

In these reactions two or more reagents are combined together in the same flask to yield a product containing almost all the atoms of the starting materials.

RESULTS

The scope of this review is to present an overview of the application of multicomponent reactions in the synthesis of compounds endowed with antiviral activity. The syntheses are classified depending on the viral target.

CONCLUSION

Multicomponent reactions can be applied to all the stages of the drug discovery and development process making them very useful in the search for new agents active against emerging (viral) pathogens.

Finding the structural requirements of diverse HIV-1 protease inhibitors using multiple QSAR modelling for lead identification

Multiple Quantitative Structure-Activity Relationship (QSAR) analysis is widely used in drug discovery for lead identification. Human Immunodeficiency Virus (HIV) protease is one of the key targets for the treatment of Acquired Immunodeficiency Syndrome (AIDS). One of the major challenges for the design of HIV-1 protease inhibitors (HIV PRIs) is to increase the inhibitory activities against the enzyme to a level where the problem associated to drug resistance may be considerably delayed. Herein, chemometric analyses were performed with 346 structurally diverse HIV PRIs with experimental bioactivities against a sub-type B mutant to develop highly predictable QSAR models and also to identify the effective structural determinants for higher affinity against HIV PR. The QSAR models were developed using OCHEM-based machine learning tools (ASNN, FSMLR, KNN, RF, MANN and XGBoost), with descriptors calculated by eight different software packages. Simultaneously, a Monte Carlo optimization-based QSAR modelling was performed using SMILES and graph-based descriptors to understand fragment and topochemical contributions. To validate the actual predictability of all these models, an additional set of 104 compounds (also with known experimental activities) with slightly different chemical space were employed. This ligand-based study serves as a crucial benchmark for further development of the HIV protease inhibitors with improved activities.

Use of multicomponent reactions in developing small-molecule tools to study GABAA receptor mechanism and function

We discuss the potential use of multicomponent reactions in developing small-molecule probes of GABA(A) receptor function. Two examples that illustrate this approach are presented: the synthesis of a class of compounds that specifically modulate the function of GABA(A) receptors containing the δ-subunit, and also 'caged' GABA derivatives. A caged GABA is a photolabile precursor of GABA that releases GABA upon photolysis.

Efficient and diverse synthesis of indole derivatives

A convergent 2-step procedure toward an array of indole derivatives involving an Ugi reaction and a Pictet-Spengler reaction is described. The reactions are versatile regarding different starting materials. Hexacyclic 24 can be produced with unprecedented complexity.

Novel macromolecular inhibitors of human immunodeficiency virus-1 protease

An intracellularly expressed defective human immunodeficiency virus type-1 (HIV-1) protease (PR) monomer could function as a dominant-negative inhibitor of the enzyme that requires dimerization for activity. Based on in silico studies, two mutant PRs harboring hydrophilic mutations, capable of forming favorable inter- and intra-subunit interactions, were selected: PR(RE) containing Asp25Arg and Gly49Glu mutations, and PR(RER) containing an additional Ile50Arg mutation. The mutants were expressed and tested by PR assays, nuclear magnetic resonance (NMR) and cell culture experiments. The mutant PRs showed dose-dependent inhibition of the wild-type PR in a fluorescent microtiter plate PR assay. Furthermore, both mutants were retained by hexahistidine-tagged wild-type HIV-1 PR immobilized on nickel-chelate affinity resin. For the first time, heterodimerization between wild-type and dominant-negative mutant PRs were also demonstrated by NMR spectroscopy. (1)H-(15)N Heteronuclear Single Quantum Coherence NMR spectra showed that although PR(RE) has a high tendency to aggregate, PR(RER) exists mainly as a folded monomer at 25-35 microM concentration, but in the presence of wild-type PR in a ratio of 1:1, heterodimerization occurs with both mutants. While the recombinant virus containing the PR(RE) sequence showed only very low level of expression, expression of the viral proteins of the virus with the PR(RER) sequence was comparable with that of the wild-type. In cell culture experiments, infectivity of viral particles containing PR(RER) protein was reduced by 82%, at mutant to wild-type infective DNA ratio of 2:1.

Desosamine in multicomponent reactions

Desosamine occurring ubiquitously in natural products is introduced into isocyanide based multicomponent reaction chemistry. Corresponding products are of potential interest for the design of novel antibiotics.

Modulators and Inhibitors of γ- and β-Secretases

Most gene mutations associated with Alzheimer's disease point to the metabolism of amyloid precursor protein as a potential cause. The beta- and gamma-secretases are two executioners of amyloid precursor protein processing resulting in amyloid-beta. Significant progress has been made in the selective inhibition of both proteases, regardless of structural information for gamma-secretase. Several peptidic and nonpeptidic leads were identified for both targets.

Beta-lactam compounds as apparently uncompetitive inhibitors of HIV-1 protease

Compounds of a combinatorial monocyclic beta-lactam library were found to be apparently uncompetitive inhibitors of HIV-1 protease, providing lead compounds for a new class of HIV protease inhibitors.