Substituted 2-aminothiazoles are exceptional inhibitors of neuronal degeneration in tau-driven models of Alzheimer's disease

Electrochemical Synthesis of α-Thiocyanated/Methoxylated Ketones Using Enol Acetates

We have developed the synthesis of α-substituted ketone compounds with enol acetates in an electrochemical way. By using cheap NH4SCN and MeOH as the radical sources, a series of valuable α-thiocyanates/methoxy ketones were synthesized under mild electrolysis conditions in acceptable yields with diverse functional group compatibility. Additionally, the scale-up experiment and synthetic transformations reveal potential applications in organic synthesis.

Recent advances of heterocycle based anticancer hybrids

Cancer is one of the major causes of death across the world. Cancer is a broad word that encompasses a wide range of illnesses that can affect any part of the body. Cancer research has increased understanding of molecular biology and cellular biology, resulting in new cancer therapies. Despite of adverse effects, surgery, radiation, and anticancer medicines are the modern cancer treatments. Keeping in mind the excellent anticancer activity exhibited by various heterocyclics, various medicines with heterocyclic moiety have been developed to identify particular target regions. The chapter aims to discuss new discoveries in the field of anticancer pharmaceuticals comprising the thiazole, pyrazole, oxazole, and triazole rings over the last five years. The proposed anticancer drugs have a lot of future significance due to their high potency.

Synthesis, Crystal Structure and Biological Evaluation of Novel 2-Phenylthiazole Derivatives as Multi-Targeting Agents to Treat Alzheimer's Disease

Three novel 2-phenylthiazole derivatives were synthesised and characterised by spectroscopic techniques. The structure of the synthesised compounds was unambiguously confirmed by a single-crystal X-ray diffraction analysis of ethyl 2-(4-{[5-(4-benzylpiperidin-1-yl)pentyl]oxy}phenyl)thiazole-4-carboxylate. All of the compounds presented good cholinesterase-inhibition activities and ethyl 2-(4-{[5-(4-benzylpiperidin-1-yl)pentyl]oxy}phenyl)thiazole-4-carboxylate showed the best acetylcholinesterase-inhibition and butyrylcholinesterase-inhibition abilities with IC50 values of 5.19 μM and 5.83 μM. The docking study demonstrated that it could interact with both the catalytic active site (CAS) and the peripheral anionic site (PAS) of acetylcholinesterase and could chelate with metal ions like Cu2+ and Zn2+.

Creating a hyperpolarised pseudo singlet state through polarisation transfer from parahydrogen under SABRE

The creation of magnetic states that have long lifetimes has been the subject of intense investigation, in part because of their potential to survive the time taken to travel from the point of injection in a patient to the point where a clinically diagnostic MRI trace is collected. We show here that it is possible to harness the signal amplification by reversible exchange (SABRE) process to create such states in a hyperpolarised form that improves their detectability in seconds without the need for any chemical change by reference to the model substrate 2-aminothiazole. We achieve this by transferring Zeeman derived polarisation that is 1500 times larger than that normally available at 400 MHz with greater than 90% efficiency into the new state, which in this case has a 27 second lifetime.

Azaphilones inhibit tau aggregation and dissolve tau aggregates in vitro

The aggregation of the microtubule-associated protein tau is a seminal event in many neurodegenerative diseases, including Alzheimer's disease. The inhibition or reversal of tau aggregation is therefore a potential therapeutic strategy for these diseases. Fungal natural products have proven to be a rich source of useful compounds having wide varieties of biological activities. We have previously screened Aspergillus nidulans secondary metabolites for their ability to inhibit tau aggregation in vitro using an arachidonic acid polymerization protocol. One aggregation inhibitor identified was asperbenzaldehyde, an intermediate in azaphilone biosynthesis. We therefore tested 11 azaphilone derivatives to determine their tau assembly inhibition properties in vitro. All compounds tested inhibited tau filament assembly to some extent, and four of the 11 compounds had the advantageous property of disassembling preformed tau aggregates in a dose-dependent fashion. The addition of these compounds to the tau aggregates reduced both the total length and number of tau polymers. The most potent compounds were tested in in vitro reactions to determine whether they interfere with tau's normal function of stabilizing microtubules (MTs). We found that they did not completely inhibit MT assembly in the presence of tau. These derivatives are very promising lead compounds for tau aggregation inhibitors and, more excitingly, for compounds that can disassemble pre-existing tau filaments. They also represent a new class of anti-tau aggregation compounds with a novel structural scaffold.

Thiazole: a promising heterocycle for the development of potent CNS active agents

Thiazole is a valuable scaffold in the field of medicinal chemistry and has accounted to display a variety of biological activities. Thiazole and its derivatives have attracted continuing interest to design various novel CNS active agents. In the past few decades, thiazoles have been widely used to develop a variety of therapeutic agents against numerous CNS targets. Thiazole containing drug molecules are currently being used in treatment of various CNS disorders and a number of thiazole derivatives are also presently in clinical trials. A lot of research has been carried out on thiazole and their analogues, which has proved their efficacy to overcome several CNS disorders in rodent as well as primate models. The aim of present review is to highlights diverse CNS activities displayed by thiazole and their derivatives. SAR of this nucleus has also been well discussed. This review covers the recent updates present in literature and will surely provide a greater insight for the designing and development of potent thiazole based CNS active agents in future.

Pharmacogenomics of Alzheimer's disease: novel therapeutic strategies for drug development

Alzheimer's disease (AD) is a major problem of health and disability, with a relevant economic impact on our society. Despite important advances in pathogenesis, diagnosis, and treatment, its primary causes still remain elusive, accurate biomarkers are not well characterized, and the available pharmacological treatments are not cost-effective. As a complex disorder, AD is a polygenic and multifactorial clinical entity in which hundreds of defective genes distributed across the human genome may contribute to its pathogenesis. Diverse environmental factors, cerebrovascular dysfunction, and epigenetic phenomena, together with structural and functional genomic dysfunctions, lead to amyloid deposition, neurofibrillary tangle formation, and premature neuronal death, the major neuropathological hallmarks of AD. Future perspectives for the global management of AD predict that genomics and proteomics may help in the search for reliable biomarkers. In practical terms, the therapeutic response to conventional drugs (cholinesterase inhibitors, multifactorial strategies) is genotype-specific. Genomic factors potentially involved in AD pharmacogenomics include at least five categories of gene clusters: (1) genes associated with disease pathogenesis; (2) genes associated with the mechanism of action of drugs; (3) genes associated with drug metabolism (phase I and II reactions); (4) genes associated with drug transporters; and (5) pleiotropic genes involved in multifaceted cascades and metabolic reactions. The implementation of pharmacogenomic strategies will contribute to optimize drug development and therapeutics in AD and related disorders.

Novel acetamidothiazole derivatives: synthesis and in vitro anticancer evaluation

A novel series of acetamide derivatives possessing both 2-imino-4-arylthiazoles and morpholine or different piperazines were synthesized and characterized by IR, (1)H NMR, (13)C NMR, elemental and mass spectral analyses. Twelve compounds were granted NSC codes at National Cancer Institute (NCI), USA for anticancer activity at a single high dose (10(-5) M) in full NCI 60 cell panel. Among the compounds tested, compounds 5a and 6b were found to be the most active candidates of the synthesized series. Assessment of toxicities, druglikeness, and drug score profiles of compounds 5a and 6b are promising. Some of the synthesized compounds showed a good docking score with potential anticancer targets, chosen based on pharmacophore mapping of the established derivatives.

Existence of dynamic tautomerism and divalent N(I) character in N-(pyridin-2-yl)thiazol-2-amine

N-(pyridin-2-yl)thiazol-2-amine is a versatile chemical functional unit present in many therapeutically important species. Quantum chemical analysis shows that there are six competitive isomeric structures possible for this class of compounds within a relative energy difference of ∼4 kcal/mol. Some of the isomeric structures possess divalent N(I) character. There appears to be a competition between the thiazole and pyridine groups to accommodate the tautomeric hydrogen, and consequently show electron donating property in the structure with R-N←L representation. Details of electron distribution, tautomeric preferences, protonation energy, and divalent N(I) character, and so on, of this class of compounds are presented in this article. Subsequently, upon protonation, (L→N←L)(⊕) character is clearly evident in these moieties as molecular orbital analysis clearly shows two lone pairs of electrons on the central nitrogen, in this system.

Substituted 2-[(2-Oxo-2H-[1,2,4]triazino [2,3-c]quinazolin-6-yl)thio]acetamides with Thiazole and Thiadiazole Fragments: Synthesis, Physicochemical Properties, Cytotoxicity, and Anticancer Activity

The series of novel N-R-2-[(3-R-2-oxo-2H-[1,2,4]triazino[2,3-c]quinazolin-6-yl)thio]acetamides with thiazole and thiadiazole fragments in a molecule were obtained by alkylation of potassium salts 1.1–1.4 by N-hetaryl-2-chloroacetamides and by aminolysis of activated acids 2.1–2.4 with N,N’-carbonyldiimidazole (CDI). The structures of compounds were determined by IR, ¹H NMR, MS, and EI-MS analysis. The results of cytotoxicity evaluated by the bioluminescence inhibition of bacterium Photobacterium leiognathi, Sh1 showed that the compounds have considerable cytotoxicity. The synthesized compounds were tested for anticancer activity in NCI against 60 cell lines. Among the highly active compounds 3.1, 3.2, and 6.5, 2-[(3-methyl-2-oxo-2H-[1,2,4]triazino[2,3-c]quinazolin-6-yl)thio]-N-(1,3-thiazol-2-yl)acetamide (3.1) was found to be the most active anticancer agent against the cell lines of colon cancer (GI₅₀ at 0.41–0.69 μM), melanoma (GI₅₀ 0.48–13.50 μM), and ovarian cancer (GI₅₀ 0.25–5.01 μM). The structure-activity relationship (SAR-analysis) was discussed.

Tau as a therapeutic target in neurodegenerative disease

Tau is a microtubule-associated protein thought to help modulate the stability of neuronal microtubules. In tauopathies, including Alzheimer's disease and several frontotemporal dementias, tau is abnormally modified and misfolded resulting in its disassociation from microtubules and the generation of pathological lesions characteristic for each disease. A recent surge in the population of people with neurodegenerative tauopathies has highlighted the immense need for disease-modifying therapies for these conditions, and new attention has focused on tau as a potential target for intervention. In the current work we summarize evidence linking tau to disease pathogenesis and review recent therapeutic approaches aimed at ameliorating tau dysfunction. The primary therapeutic tactics considered include kinase inhibitors and phosphatase activators, immunotherapies, small molecule inhibitors of protein aggregation, and microtubule-stabilizing agents. Although the evidence for tau-based treatments is encouraging, additional work is undoubtedly needed to optimize each treatment strategy for the successful development of safe and effective therapeutics.