Challenges and opportunities of trapping ligands

Fused thiophene as a privileged scaffold: A review on anti-Alzheimer's disease potentials via targeting cholinesterases, monoamine oxidases, glycogen synthase kinase-3, and Aβ aggregation

As a "silent threat," Alzheimer's disease (AD) is quickly rising to the top of the list of costly and troublesome diseases facing humanity. It is growing to be one of the most troublesome and expensive conditions, with annual health care costs higher than those of cancer and comparable to those of cardiovascular disorders. One of the main pathogenic characteristics of AD is the deficiency of the neurotransmitter acetylcholine (ACh) which plays a vital role in memory, learning, and attention. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) play a crucial role in hydrolyzing ACh. Consequently, a frequent therapy approach for AD is the suppression of AChE and BChE to improve cholinergic neurotransmission and reduce cognitive symptoms. The accumulation of amyloid plaques (Aβ) is a primary factor contributing to neurodegenerative diseases, particularly AD. Glycogen synthase kinase-3β (GSK3-β) is regarded as a pivotal player in the pathophysiology of AD since dysregulation of this kinase affects all major hallmarks of the disease, such as tau phosphorylation, Aβ aggregation, memory, neurogenesis, and synaptic function. One of the most challenging and risky issues in modern medicinal chemistry is the urgent and ongoing need for the study and development of effective therapeutic candidates for the treatment of AD. A significant class of heterocyclic molecules that can target the complex and multifactorial pathogenesis of AD are fused thiophene derivatives. The goal of the current review is to demonstrate the advancements made in fused thiophene derivatives' anti-AD activity. It also covers their mechanisms of action and studies of the structure-activity relationships in addition to the compilation of significant synthetic routes for fused thiophene derivatives with anti-AD potential. This review is intended to stimulate new ideas in the search for more rationale designs of derivatives based on fused thiophene, hoping to be more potent in treating AD.

Cyclizations of Alkenyl(Alkynyl)-Functionalized Quinazolinones and their Heteroanalogues: A Powerful Strategy for the Construction of Polyheterocyclic Structures

Quinazolin-4-one, its heteroanalogues, and derivatives represent an outstandingly important class of compounds in modern organic, medicinal, and pharmaceutical chemistry, as these molecular structures are noted for their wide synthetic and pharmacological potential. In the last years, ever-increasing research attention has been paid to quinazolinone derivatives bearing alkenyl and alkynyl substituents on the pyrimidinone nucleus. The original structural combination of synthetically powerful endocyclic amidine (or amidine-related) and exocyclic unsaturated moieties provides a driving force for cyclizations, which offer an efficient toolkit to construct a variety of fused pyrimidine systems with saturated N- and N,S-heterocycles. In this connection, the present review article is mainly aimed at systematic coverage of the progress in using alkenyl(alkynyl)quinazolinones and their heteroanalogues as convenient bifunctional substrates for regioselective annulation of small- and medium-sized heterocyclic nuclei. Much attention is paid to elucidating the structural and electronic effects of reagents on the regio- and stereoselectivity of the cyclizations as well as to clarifying the relevant reaction mechanisms.

Drug Reprofiling to Identify Potential HIV-1 Protease Inhibitors

The use of protease inhibitors in human immunodeficiency virus type 1 (HIV-1) treatment is limited by adverse effects, including metabolic complications. To address these challenges, efforts are underway in the pursuit of more potent and less toxic HIV-1 protease inhibitors. Repurposing existing drugs offers a promising avenue to expedite the drug discovery process, saving both time and costs compared to conventional de novo drug development. This study screened FDA-approved and investigational drugs in the DrugBank database for their potential as HIV-1 protease inhibitors. Molecular docking studies and cell-based assays, including anti-HIV-1 in vitro assays and XTT cell viability tests, were conducted to evaluate their efficacy. The study findings revealed that CBR003PS, an antibiotic currently in clinical use, and CBR013PS, an investigational drug for treating endometriosis and uterine fibroids, exhibited significant binding affinity to the HIV-1 protease with high stability. Their EC50 values, measured at 100% cell viability, were 9.4 nM and 36.6 nM, respectively. Furthermore, cell-based assays demonstrated that these two compounds showed promising results, with therapeutic indexes higher than 32. In summary, based on their favorable therapeutic indexes, CBR003PS and CBR013PS show potential for repurposing as HIV-1 protease inhibitors.

Thieno[2,3-d]pyrimidine as a promising scaffold in medicinal chemistry: Recent advances

Thienopyrimidine scaffold is a fused heterocyclic ring system that structurally can be considered as adenine, the purine base that is found in both DNA and RNA-bioisosteres. Thienopyrimidines exist in three distinct isomeric forms. The current review discusses thieno[2,3-d]pyrimidine as a one of the opulent heterocycles in drug discovery. Its broad range of medical applications such as anticancer, anti-inflammatory, anti-microbial, and CNS protective agents has inspired us to study its structure-activity relationship (SAR), along with its relevant synthetic strategies. The present review briefly summarizes synthetic approaches for the preparation of thieno[2,3-d]pyrimidine derivatives. In addition, the promising biological activities of this scaffold are also illustrated with explanatory diagrams for their SAR studies.

New Frontier in Glycoprotein Hormones and Their Receptors Structure-Function

Last two decades of structure-function studies performed in numerous laboratories provided substantial progress in understanding basic science, physiological, pathophysiological, pharmacological, and comparative aspects of glycoprotein hormones (GPHs) and their cognate receptors. Multiple concepts and models developed based on experimental data in the past stood the test of time and have been, at least in part, confirmed and/or remained compatible with the new structures resolved at the atomic level. Major advances in understanding of the ligand-receptor relationships are heralding the dawn of a new era for GPHs and their receptors, although many basic questions still remain unanswered. This article examines retrospectively several basic science aspects of GPH super-agonists and related "biosuperiors" in a broader context of the advances in the ligand-receptor structure-function relationships and new mechanistic models generated based on the structure elucidation. Due to selective focus of my comments and perspectives in certain parts, the reader is directed to the most relevant publications and reviews in the field for more comprehensive analyses.