Design and synthesis of new (E)-cinnamic N-acylhydrazones as potent antitrypanosomal agents

Synthesis and pharmacological evaluation of novel N-aryl-cinnamoyl-hydrazone hybrids designed as neuroprotective agents for the treatment of Parkinson's disease

Molecular hybridization between structural fragments from the structures of curcumin (1) and resveratrol (2) was used as a designing tool to generate a new N-acyl-cinnamoyl-hydrazone hybrid molecular architecture. Twenty-eight new compounds were synthesized and evaluated for multifunctional activities related to Parkinson's disease (PD), including neuroprotection, antioxidant, metal chelating ability, and Keap1/Nrf2 pathway activation. Compounds 3b (PQM-161) and 3e (PQM-164) were highlighted for their significant antioxidant profile, acting directly as induced free radical stabilizers by DPPH and indirectly by modulating intracellular inhibition of t-BOOH-induced ROS formation in neuronal cells. The mechanism of action was determined as a result of Keap1/Nrf2 pathway activation by both compounds and confirmed by different experiments. Furthermore, compound 3e (PQM-164) exhibited a significant effect on the accumulation of α-synuclein and anti-inflammatory activity, leading to an expressive decrease in gene expression of iNOS, IL-1β, and TNF-α. Overall, these results highlighted compound 3e as a promising and innovative multifunctional drug prototype candidate for PD treatment.

Integrated Computational Approaches for Drug Design Targeting Cruzipain

Cruzipain inhibitors are required after medications to treat Chagas disease because of the need for safer, more effective treatments. Trypanosoma cruzi is the source of cruzipain, a crucial cysteine protease that has driven interest in using computational methods to create more effective inhibitors. We employed a 3D-QSAR model, using a dataset of 36 known inhibitors, and a pharmacophore model to identify potential inhibitors for cruzipain. We also built a deep learning model using the Deep purpose library, trained on 204 active compounds, and validated it with a specific test set. During a comprehensive screening of the Drug Bank database of 8533 molecules, pharmacophore and deep learning models identified 1012 and 340 drug-like molecules, respectively. These molecules were further evaluated through molecular docking, followed by induced-fit docking. Ultimately, molecular dynamics simulation was performed for the final potent inhibitors that exhibited strong binding interactions. These results present four novel cruzipain inhibitors that can inhibit the cruzipain protein of T. cruzi.

Structural optimization based on 4,5-dihydropyrazolo[1,5-a]quinazoline scaffold for improved insecticidal activities

The long-term and irrational application of insecticides has increased the rate of development of pest resistance and caused numerous environmental issues. To address these problems, our previous work reported that 4,5-dihydropyrazolo[1,5-a]quinazoline (DPQ) is a class of gelled heterocyclic compounds that act on insect γ-aminobutyric acid receptors (GABAR). DPQ scaffold has no cross-resistance to existing insecticides, so the development of this scaffold is an interesting task for integrated pest management. In the present study, a novel series of 4,5-dihydropyrazolo[1,5-a]quinazolines (DPQs) were designed and synthesized based on pyraquinil, a highly insecticidal compound discovered in our previous work. Insecticidal activities of the target compounds against diamondback moth (Plutella xylostella), beet armyworm (Spodoptera exigua), fall armyworm (Spodoptera frugiperda), and red imported fire ant (Solenopsis invicta Buren) were evaluated. Compounds 6 and 12 showed the best insecticidal activity against Plutella xylostella (P. xylostella) (LC50 = 1.49 and 0.97 mg/L), better than pyraquinil (LC50 = 1.76 mg/L), indoxacarb and fipronil (LC50 = 1.80 mg/L). Meanwhile, compound 12 showed slow toxicity to Solenopsis invicta Buren (S. invicta), with a 5 d mortality rate of 98.89% at 0.5 mg/L that is similar to fipronil. Moreover, Electrophysiological studies against the PxRDL1 GABAR heterologously expressed in Xenopus oocytes indicated that compound 12 could act as a potent GABA receptor antagonist (2 μΜ, inhibition rate, 68.25%). Molecular docking results showed that Ser285 (chain A) and Thr289 (chain D) of P. xylostella GABAR participated in hydrogen bonding interactions with compound 12, and density functional theory (DFT) calculations suggested the importance of pyrazolo[1,5-a]quinazoline core in potency. This systematic study provides valuable clues for the development of DPQ scaffold in the field of agrochemicals, and compound 12 can be further developed as an insecticide and bait candidate.

Synthesis, X-ray Structure, Hirshfeld, DFT Conformational, Cytotoxic, and Anti-Toxoplasma Studies of New Indole-Hydrazone Derivatives

The hydrazones 3a-c, were synthesized from the reaction of indole-3-carbaldehyde and nicotinic acid hydrazide, isonicotinic acid hydrazide, and benzoic acid hydrazide, respectively. Their structures were confirmed using FTIR, 1HNMR, and 13CNMR spectroscopic techniques. Exclusively, hydrazones 3b and 3c were confirmed using single crystal X-ray crystallography to exist in the Eanti form. With the aid of DFT calculations, the most stable configuration of the hydrazones 3a-c in gas phase and in nonpolar solvents (CCl4 and cyclohexane) is the ESyn form. Interestingly, the DFT calculations indicated the extrastability of the EAnti in polar aprotic (DMSO) and polar protic (ethanol) solvents. Hirshfeld topology analysis revealed the importance of the N…H, O…H, H…C, and π…π intermolecular interactions in the molecular packing of the studied systems. Distribution of the atomic charges for the hydrazones 3a-c was presented. The hydrazones 3a-c showed a polar character where 3b has the highest polarity of 5.7234 Debye compared to the 3a (4.0533 Debye) and 3c (5.3099 Debye). Regarding the anti-toxoplasma activity, all the detected results verified that 3c had a powerful activity against chronic toxoplasma infection. Compound 3c showed a considerable significant reduction percent of cyst burden in brain homogenates of toxoplasma infected mice representing 49%.

I2/DMSO-Promoted Synthesis of Diaryl Sulfide- and Selenide-Embedded Arylhydrazones

Functionalization and derivatization of arylhydrazones are important in pharmaceutical, medicinal, material, and coordination chemistry. In this regard, a facile I₂/DMSO-promoted cross-dehydrogenative coupling (CDC) for direct sulfenylation and selenylation of arylhydrazones has been accomplished utilizing arylthiols/arylselenols at 80 °C. This method provides a metal-free benign route for the synthesis of a variety of arylhydrazones embedded with diverse diaryl sulfide and selenide moieties in good to excellent yield. In this reaction, molecular I₂ acts as a catalyst, and DMSO is utilized as a mild oxidant as well as solvent to produce several sulfenyl and selenyl arylhydrazones through a CDC-mediated catalytic cycle.

Ultrasound-Assisted Synthesis of Piperidinyl-Quinoline Acylhydrazones as New Anti-Alzheimer's Agents: Assessment of Cholinesterase Inhibitory Profile, Molecular Docking Analysis, and Drug-like Properties

Alzheimer's disease (AD) is one of the progressive neurological disorders and the main cause of dementia all over the world. The multifactorial nature of Alzheimer's disease is a reason for the lack of effective drugs as well as a basis for the development of new structural leads. In addition, the appalling side effects such as nausea, vomiting, loss of appetite, muscle cramps, and headaches associated with the marketed treatment modalities and many failed clinical trials significantly limit the use of drugs and alarm for a detailed understanding of disease heterogeneity and the development of preventive and multifaceted remedial approach desperately. With this motivation, we herein report a diverse series of piperidinyl-quinoline acylhydrazone therapeutics as selective as well as potent inhibitors of cholinesterase enzymes. Ultrasound-assisted conjugation of 6/8-methyl-2-(piperidin-1-yl)quinoline-3-carbaldehydes (4a,b) and (un)substituted aromatic acid hydrazides (7a-m) provided facile access to target compounds (8a-m and 9a-j) in 4-6 min in excellent yields. The structures were fully established using spectroscopic techniques such as FTIR, ¹H- and ¹³C NMR, and purity was estimated using elemental analysis. The synthesized compounds were investigated for their cholinesterase inhibitory potential. In vitro enzymatic studies revealed potent and selective inhibitors of AChE and BuChE. Compound 8c showed remarkable results and emerged as a lead candidate for the inhibition of AChE with an IC₅₀ value of 5.3 ± 0.51 µM. The inhibitory strength of the optimal compound was 3-fold higher compared to neostigmine (IC₅₀ = 16.3 ± 1.12 µM). Compound 8g exhibited the highest potency and inhibited the BuChE selectively with an IC₅₀ value of 1.31 ± 0.05 µM. Several compounds, such as 8a-c, also displayed dual inhibitory strength, and acquired data were superior to the standard drugs. In vitro results were further supported by molecular docking analysis, where potent compounds revealed various important interactions with the key amino acid residues in the active site of both enzymes. Molecular dynamics simulation data, as well as physicochemical properties of the lead compounds, supported the identified class of hybrid compounds as a promising avenue for the discovery and development of new molecules for multifactorial diseases, such as Alzheimer's disease (AD).

Piperine-Chlorogenic Acid Hybrid Inhibits the Proliferation of the SK-MEL-147 Melanoma Cells by Modulating Mitotic Kinases

Melanoma is considered the most aggressive form of skin cancer, showing high metastatic potential and persistent high mortality rates despite the introduction of immunotherapy and targeted therapies. Thus, it is important to identify new drug candidates for melanoma. The design of hybrid molecules, with different pharmacophore fragments combined in the same scaffold, is an interesting strategy for obtaining new multi-target and more effective anticancer drugs. We designed nine hybrid compounds bearing piperine and chlorogenic acid pharmacophoric groups and evaluated their antitumoral potential on melanoma cells with distinct mutational profiles SK-MEL-147, CHL-1 and WM1366. We identified the compound named PQM-277 (3a) to be the most cytotoxic one, inhibiting mitosis progression and promoting an accumulation of cells in pro-metaphase and metaphase by altering the expression of genes that govern G2/M transition and mitosis onset. Compound 3a downregulated FOXM1, CCNB1, CDK1, AURKA, AURKB, and PLK1, and upregulated CDKN1A. Molecular docking showed that 3a could interact with the CUL1-RBX1 complex, which activity is necessary to trigger molecular events essential for FOXM1 transactivation and, in turn, G2/M gene expression. In addition, compound 3a effectively induced apoptosis by increasing BAX/BCL2 ratio. Our findings demonstrate that 3a is an important antitumor candidate prototype and support further investigations to evaluate its potential for melanoma treatment, especially for refractory cases to BRAF/MEK inhibitors.

A Novel Protocol for the Synthesis of 1,2,4-Oxadiazoles Active against Trypanosomatids and Drug-Resistant Leukemia Cell Lines

Cancer and parasitic diseases, such as leishmaniasis and Chagas disease, share similarities that allow the co-development of new antiproliferative agents as a strategy to quickly track the discovery of new drugs. This strategy is especially interesting regarding tropical neglected diseases, for which chemotherapeutic alternatives are extremely outdated. We designed a series of (E)-3-aryl-5-(2-aryl-vinyl)-1,2,4-oxadiazoles based on the reported antiparasitic and anticancer activities of structurally related compounds. The synthesis of such compounds led to the development of a new, fast, and efficient strategy for the construction of a 1,2,4-oxadiazole ring on a silica-supported system under microwave irradiation. One hit compound (23) was identified during the in vitro evaluation against drug-sensitive and drug-resistant chronic myeloid leukemia cell lines (EC₅₀ values ranging from 5.5 to 13.2 µM), Trypanosoma cruzi amastigotes (EC₅₀ = 2.9 µM) and Leishmania amazonensis promastigotes (EC₅₀ = 12.2 µM) and amastigotes (EC₅₀ = 13.5 µM). In silico studies indicate a correlation between the in vitro activity and the interaction with tubulin at the colchicine binding site. Furthermore, ADMET in silico predictions indicate that the compounds possess a high druggability potential due to their physicochemical, pharmacokinetic, and toxicity profiles, and for hit 23, it was identified by multiple spectroscopic approaches that this compound binds with human serum albumin (HSA) via a spontaneous ground-state association with a moderate affinity driven by entropically and enthalpically energies into subdomain IIA (site I) without significantly perturbing the secondary content of the protein.

Identification of Novel Functionalized Carbohydrazonamides Designed as Chagas Disease Drug Candidates

BACKGROUND

Although several research efforts have been made worldwide to discover novel drug candidates for the treatment of Chagas disease, the nitroimidazole drug benznidazol remains the only therapeutic alternative in the control of this disease. However, this drug presents reduced efficacy in the chronic form of the disease and limited safety after long periods of administration, making it necessary to search for new, more potent and safe prototypes.

OBJECTIVE

We described herein the synthesis and the trypanocidalaction of new functionalized carbohydrazonamides (2-10) against trypomastigote forms of Trypanosoma cruzi.

METHODS

These compounds were designed through the application of molecular hybridization concept between two potent anti-T. cruzi prototypes, the nitroimidazole derivative megazol (1) and the cinnamyl N-acylhydrazone derivative (14) which have been shown to be twice as potent in vitro as benznidazole.

RESULTS

The most active compounds were the (Z)-N'-((E)-3-(4-nitrophenyl)-acryloyl)-1-methyl-5- nitro-1H-imidazol-2-carbohydrazonamide (6) (IC50=9.50 μM) and the (Z)-N'-((E)-3-(4- hydroxyphe-nyl)-acryloyl)-1-methyl-5-nitro-1H-imidazol-2-carbohydrazonamide (8) (IC50=12.85 μM), which were almost equipotent to benznidazole (IC50=10.26 μM) used as standard drug. The removal of the amine group attached to the imine subunit in the corresponding N-acylhydrazone derivatives (11-13) resulted in less potent or inactive compounds. The para-hydroxyphenyl derivative (8) presented also a good selectivity index (SI = 32.94) when tested against mammalian cells from Swiss mice.

CONCLUSION

The promising trypanocidal profile of new carbohydrazonamide derivatives (6) and (8) was characterized. These compounds have proved to be a good starting point for the design of more effective trypanocidal drug candidates.

Evaluation of trypanocidal properties of ferrocenyl and cyrhetrenyl N-acylhydrazones with pendant 5-nitrofuryl group

Four N-acylhydrazones of general formulae [R¹-C(O)-NH-N=C(R²)(5-nitrofuryl)] with (R¹ = ferrocenyl or cyrhetrenyl and R² = H or Me) are synthesized and characterized in solution and in the solid-state. Comparative studies of their stability in solution under different experimental conditions and their electrochemical properties are reported. NMR studies reveal that the four compounds are stable in DMSO‑d₆ and complementary UV-Vis studies confirm that they also exhibit high stability in mixtures DMSO:H₂O at 37 °C. Electrochemical studies show that the half-wave potential of the nitro group of the N-acylhydrazones is smaller than that of the standard drug nifurtimox and the reduction process follows a self-protonation mechanism. In vitro studies on the antiparasitic activities of the four complexes and the nifurtimox against Trypanosoma cruzi and Trypanosoma brucei reveal that: i) the N-acylhydrazones have a potent inhibitory growth activity against both parasites [EC₅₀ in the low micromolar (in T. cruzi) or even in the nanomolar (in T. brucei) range] and ii) cyrhetrenyl derivatives are more effective than their ferrocenyl analogs. Parallel studies on the L₆ rat skeletal myoblast cell line have also been conducted, and the selectivity indexes determined. Three of the four N-acylhydrazones showed higher selectivity towards T. brucei than the standard drug nifurtimox. Additional studies suggest that the organometallic compounds are bioactivated by type I nitroreductase enzymes.

Predictive Global Models of Cruzain Inhibitors with Large Chemical Coverage

Chagas disease affects 8-11 million people worldwide, most of them living in Latin America. Moreover, migratory phenomena have spread the infection beyond endemic areas. Efforts for the development of new pharmacological therapies are paramount as the pharmacological profile of the two marketed drugs currently available, nifurtimox and benznidazole, needs to be improved. Cruzain, a parasitic cysteine protease, is one of the most attractive biological targets due to its roles in parasite survival and immune evasion. In this work, we compiled and curated a database of diverse cruzain inhibitors previously reported in the literature. From this data set, quantitative structure-activity relationship (QSAR) models for the prediction of their pIC50 values were generated using k-nearest neighbors and random forest algorithms. Local and global models were calculated and compared. The statistical parameters for internal and external validation indicate a significant predictability, with q loo 2 values around 0.66 and 0.61 and external R 2 coefficients of 0.725 and 0.766. The applicability domain is quantitatively defined, according to QSAR good practices, using the leverage and similarity methods. The models described in this work are readily available in a Python script for the discovery of novel cruzain inhibitors.

The synthesis and antiproliferative activity of new N-allyl quinoxalinecarboxamides and their O-regioisomers

We have designed a series of quinoxalinepeptidomimetic derivatives based on our previously reported scaffold in an attempt to find a promising lead compound.

Synthesis and Biological Activity of Hydrazones and Derivatives: A Review

Hydrazones and their derivatives are very important compounds in medicinal chemistry due to their reported biological activity for the treatment of several diseases, like Alzheimer's, cancer, inflammation, and leishmaniasis. However, most of the investigations on hydrazones available in literature today are directed to the synthesis of these molecules with little discussion available on their biological activities. With the purpose of bringing lights into this issue, we performed a revision of the literature and wrote this review based on some of the most current research reports of hydrazones and derivatives, making it clear that the synthesis of these molecules can lead to new drug prototypes. Our goal is to encourage more studies focused on the synthesis and evaluation of new hydrazones, as a contribution to the development of potential new drugs for the treatment of various diseases.

Functionalized 3-(5-ar-yloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1-(4-substituted-phen-yl)prop-2-en-1-ones: synthetic pathway, and the structures of six examples

Five examples each of 3-(5-ar-yloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1-[4-(prop-2-yn-1-yl-oxy)phen-yl]prop-2-en-1-ones and the corresponding 1-(4-azido-phen-yl)-3-(5-ar-yloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)prop-2-en-1-ones have been synthesized in a highly efficient manner, starting from a common source precursor, and structures have been determined for three examples of each type. In each of 3-[5-(2-chloro-phen-oxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-yn-1-yl-oxy)phen-yl]prop-2-en-1-one, C28H21ClN2O3, (Ib), the isomeric 3-[5-(2-chloro-phen-oxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-yn-1-yl-oxy)phen-yl]prop-2-en-1-one, (Ic), and 3-[3-methyl-5-(naphthalen-2-yl-oxy)-1-phenyl-1H-pyrazol-4-yl]-1-[4-(prop-2-yn-yloxy)phen-yl]prop-2-en-1-one, C32H24N2O3, (Ie), the mol-ecules are linked into chains of rings, formed by two independent C-H⋯O hydrogen bonds in (Ib) and by a combination of C-H⋯O and C-H⋯π(arene) hydrogen bonds in each of (Ic) and (Ie). There are no direction-specific inter-molecular inter-actions in the structure of 1-(4-azido-phen-yl)-3-[3-methyl-5-(2-methyl-phen-oxy)-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C26H21N5O2, (IIa). In 1-(4-azido-phen-yl)-3-[5-(2,4-di-chloro-phen-oxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C25H17Cl2N5O2, (IId), the di-chloro-phenyl group is disordered over two sets of atomic sites having occupancies 0.55 (4) and 0.45 (4), and the mol-ecules are linked by a single C-H⋯O hydrogen bond to form cyclic, centrosymmetric R 2 2(20) dimers. Similar dimers are formed in 1-(4-azido-phen-yl)-3-[3-methyl-5-(naphthalen-2-yl-oxy)-1-phenyl-1H-pyrazol-4-yl]prop-2-en-1-one, C29H21N5O2, (IIe), but here the dimers are linked into a chain of rings by two independent C-H..π(arene) hydrogen bonds. Comparisons are made between the mol-ecular conformations within both series of compounds.

Synthesis, Antitrypanosomal and Antimycobacterial Activities of Coumarin N-acylhydrazonic Derivatives

BACKGROUND

Near to 5-7 million people are infected with T. cruzi in the world, and about 10,000 people per year die of problems associated with this disease.

METHODS

Herein, the synthesis, antitrypanosomal and antimycobacterial activities of seventeen coumarinic N-acylhydrazonic derivatives have been reported.

RESULTS

These compounds were synthesized using methodology with reactions global yields ranging from 46%-70%. T. cruzi in vitro effects were evaluated against trypomastigote and amastigote, forming M. tuberculosis activity towards H37Rv sensitive strain and resistant strains.

DISCUSSION

Against T. cruzi, the more active compounds revealed only moderate activity IC₅₀/96h~20 μM for both trypomastigotes and amastigotes intracellular forms. (E)-2-oxo-N'- (3,4,5-trimethoxybenzylidene)-2H-chromene-3-carbohydrazide showed meaningful activity in INH resistant/RIP resistant strain.

CONCLUSION

These compound acting as multitarget could be good leads for the development of new trypanocidal and bactericidal agents.

p-Methoxycinnamic Acid Diesters Lower Dyslipidemia, Liver Oxidative Stress and Toxicity in High-Fat Diet Fed Mice and Human Peripheral Blood Lymphocytes

The pursuit of cholesterol lowering natural products with less side effects is needed for controlling dyslipidemia and reducing the increasing toll of cardiovascular diseases that are associated with morbidity and mortality worldwide. The present study aimed at the examining effects of p-methoxycinnamic acid diesters (PCO-C) from carnauba (Copernicia prunifera)-derived wax on cytotoxic, genotoxic responses in vitro and on dyslipidemia and liver oxidative stress in vivo, utilizing high-fat diet (HFD) chronically fed Swiss mice. In addition, we evaluated the effect of PCO-C on the expression of key cholesterol metabolism-related genes, as well as the structural interactions between PCO-C and lecithin-cholesterol acyl transferase (LCAT) in silico. Oral treatment with PCO-C was able to reduce total serum cholesterol and low-density lipoprotein (LDL) levels following HFD. In addition, PCO-C reduced excessive weight gain and lipid peroxidation, and increased the gene expression of LCAT following HFD. Furthermore, the high affinity of the studied compound (ΔG: −8.78 Kcal/mol) towards the active sites of mutant LCAT owing to hydrophobic and van der Waals interactions was confirmed using bioinformatics. PCO-C showed no evidence of renal and hepatic toxicity, unlike simvastatin, that elevated aspartate aminotransferase (AST) levels, a marker of liver dysfunction. Finally, PCO-C showed no cytotoxicity or genotoxicity towards human peripheral blood lymphocytes in vitro. Our results suggest that PCO-C exerts hypocholesterolemic effects. The safety of PCO-C in the toxicological tests performed and the reports of its beneficial biological effects render this a promising compound for the development of new cholesterol-lowering therapeutics to control dyslipidemia. More work is needed for further elucidating PCO-C role on lipid metabolism to support future clinical studies.

(R)-2-Phenyl-4,5-Dihydrothiazole-4-Carboxamide Derivatives Containing a Diacylhydrazine Group: Synthesis, Biological Evaluation, and SARs

A series of (R)-2-phenyl-4,5-dihydrothiazole-4-carboxamide derivatives containing a diacylhydrazine moiety were designed and synthesized. Their structures were confirmed by melting points, ¹H NMR, ¹³C NMR, and elemental analysis (EA). Their antifungal and insecticidal activities were evaluated. The antifungal activity result indicated that most title compounds against Cercospora arachidicola, Alternaria solani, Phytophthora capsici, and Physalospora piricola exhibited apparent antifungal activities at 50 mg/L, and better than chlorothalonil or carbendazim. The EC₅₀ values of (R)-N’-benzoyl-2-(4-chlorophenyl)-4,5-dihydrothiazole-4-carbohydrazide (I-5) against six tested phytopathogenic fungi were comparable to those of chlorothalonil. The CoMSIA model showed that a proper hydrophilic group in the R¹ position, as well as a proper hydrophilic and electron-donating group in the R² position, could improve the antifungal activity against Physalospora piricola, which contributed to the further optimization of the structures. Meanwhile, most title compounds displayed good insecticidal activities, especially compound (R)-N’-(4-nitrobenzoyl)-2-(4-nitrophenyl)-4,5-dihydrothiazole-4-carbohydrazide (III-3). The insecticidal mechanism results indicated that compound III-3 can serve as effective insect Ca²⁺ level modulators by disrupting the cellular calcium homeostasis in Mythimna separata.

Cinnamamide: An insight into the pharmacological advances and structure-activity relationships

The cinnamamide (cinnamic acid amide and cinnamide) is a privileged scaffold present widely in a number of natural products. The scaffold acts as a useful template for designing and arriving at newly drug-like molecules with potential pharmacological activity. An attempt has been made to review the extensive occurrence of cinnamamide scaffold in many lead compounds reported for treating various diseases, their binding interactions with the therapeutic targets as well as mechanism of action and their structure-activity relationships. The discoveries of cinnamamide systems and some examples of unusual cinnamamides having an aromatic, aliphatic, and heterocyclic or other rings condensed to the basic cinnamamide structure also have been extensively covered in this review.

Chalcone derivatives and their antibacterial activities: Current development

The increase in antibiotic resistance due to various factors has encouraged the look for novel compounds which are active against multidrug-resistant pathogens. In this framework, chalcone-based compounds showed a diversity of pharmacological properties, and its derivatives possess a high degree of structural diversity, and it is helpful for the discovery of new therapeutic agents. The growing resistance to antibiotics worldwide has endangered their efficacy. This has led to a surging interest in the discovery of new antibacterial agents. Thus, there is an urgent need for new antibacterial drug candidates with increased strength, new targets, low cost, superior pharmacokinetic properties, and minimum side effects. The present review concluded and focuses on the recent developments in the area of medicinal chemistry to explore the diverse chemical structures of potent antibacterial agents and also describes its structure-activity relationships studies. The various synthetic structures leading to this class of neutral protective compound is common and additional structural optimization is promising for potential drug discovery and development.

Quantitative Structure-Activity Relationships for Structurally Diverse Chemotypes Having Anti-Trypanosoma cruzi Activity

Small-molecule compounds that have promising activity against macromolecular targets from Trypanosoma cruzi occasionally fail when tested in whole-cell phenotypic assays. This outcome can be attributed to many factors, including inadequate physicochemical and pharmacokinetic properties. Unsuitable physicochemical profiles usually result in molecules with a poor ability to cross cell membranes. Quantitative structure-activity relationship (QSAR) analysis is a valuable approach to the investigation of how physicochemical characteristics affect biological activity. In this study, artificial neural networks (ANNs) and kernel-based partial least squares regression (KPLS) were developed using anti-T. cruzi activity data for broadly diverse chemotypes. The models exhibited a good predictive ability for the test set compounds, yielding q² values of 0.81 and 0.84 for the ANN and KPLS models, respectively. The results of this investigation highlighted privileged molecular scaffolds and the optimum physicochemical space associated with high anti-T. cruzi activity, which provided important guidelines for the design of novel trypanocidal agents having drug-like properties.

Research progress in the biological activities of 3,4,5-trimethoxycinnamic acid (TMCA) derivatives

TMCA (3,4,5-trimethoxycinnamic acid) ester and amide are privileged structural scaffolds in drug discovery which are widely distributed in natural products and consequently produced diverse therapeutically relevant pharmacological functions. Owing to the potential of TMCA ester and amide analogues as therapeutic agents, researches on chemical syntheses and modifications have been carried out to drug-like candidates with broad range of medicinal properties such as antitumor, antiviral, CNS (central nervous system) agents, antimicrobial, anti-inflammatory and hematologic agents for a long time. At the same time, SAR (structure-activity relationship) studies have draw greater attention among medicinal chemists, and many of the lead compounds were derived for various disease targets. However, there is an urgent need for the medicinal chemists to further exploit the precursor in developing chemical entities with promising bioactivity and druggability. This review concisely summarizes the synthesis and biological activity for TMCA ester and amide analogues. It also comprehensively reveals the relationship of significant biological activities along with SAR studies.

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3,4,5-Trimethoxycinnamic acid (TMCA) derivatives show applications in different pathophysiological conditions due to its privileged structural scaffolds.

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Natural derived TMCA analogues and chemically modified TMCA ester and amide analogues and their bioactivities are focused in this review. Additionally, it also comprehensively summarized the relationship of significant biological activities along with SAR studies of synthetic TMCA derivatives.

Lanthanide–EDTA complexes covalently bonded on Fe3O4@SiO2 magnetic nanoparticles promote the green, stereoselective synthesis of N-acylhydrazones

Highly efficient stereoselective synthesis of E–N-acylhydrazones using magnetic nanoparticles-Ln³⁺ as heterogeneous catalysts.

Synthesis and characterization of new dialkylacylphosphonylhydrazones

The present work refers to the synthesis of novel dialkylacylphosphonylhydrazones that occurs in three reaction steps: the first one is the synthesis of different dialkyl acetate phosphonoacetates obtained by the reaction of ethyl bromoacetate with the trialkyl phosphite of interest. The second one is the synthesis of acetic diethoxyphosphonylhydrazines which is from the reaction between the synthesized dialkyl phosphonoacetates and hydrazine. The third and final steps is the condensation of acetic diethoxyphosphonylhydrazides with different heterocyclic aldehydes. In total, 17 unpublished compounds, namely 1 to 17 (Table 1) were obtained with a diastereoisomeric mixture of the preferential conformation E and all the compounds were characterized by 1-H and 13-C and 31-P NMR, infrared (IR) and mass spectroscopy (MS). This work presents the characterization data of these compounds.

Synthesis and insecticidal activity study of novel anthranilic diamides analogs containing a diacylhydrazine bridge as effective Ca2+ modulators

Anthranilic diamides is a class of insecticides target at ryanodine receptors (RyRs). To discover potent insecticides targeting at RyRs, a series of novel anthranilic diamides with a diacylhydrazine bridge were designed and synthesized. Their insecticidal activities were evaluated and a preliminary structure-activity relationship (SAR) was summarized. In particular, compound 5g exhibited good lethality against oriental armyworm (Mythimna separata) at a concentration of 5 mg/L. The calcium imaging experimental results indicated that the compound 5g can serve as effective insect Ca²⁺ level modulators by disrupting the cellular calcium homeostasis in Mythimna separata (Walker) and Spodoptera exigua (Hübner), which probably activated the RyRs on the ER membrane.

In Vitro Anti-Toxoplasma gondii and Antimicrobial Activity of Amides Derived from Cinnamic Acid

Most cinnamic acids, their esters, amides, aldehydes, and alcohols present several therapeutic actions through anti-inflammatory, antitumor, and inhibitory activity against a great variety of microorganisms. In this work, eight amines derived from cinnamic acid were synthesized and tested against host cells infected with Toxoplasma gondii and the bacteria Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and three strains of Staphylococcus aureus. Compounds 3 and 4 showed the best result against intracellular T. gondii, presenting antiparasitic activity at low concentrations (0.38 and 0.77 mM). The antibacterial activity of these compounds was also evaluated by the agar microdilution method, and amides 2 and 5 had a minimum inhibitory concentration of 250 µg mL⁻¹ against two strains of S. aureus (ATCC 25923 and bovine strain LSA 88). These also showed synergistic action along with a variety of antibiotics, demonstrating that amines derived from cinnamic acid have potential as pharmacological agents.

Rational modifications on a benzylidene-acrylohydrazide antiviral scaffold, synthesis and evaluation of bioactivity against Chikungunya virus

Chikungunya virus is a re-emerging arbovirus transmitted to humans by Aedes mosquitoes, responsible for an acute febrile illness associated with painful and debilitating arthralgia, which can persist for several months or become chronic. Over the past few years, infection with this virus has spread worldwide with a previously unknown virulence. No specific antiviral treatments nor vaccines are currently available against this important pathogen. Starting from the structure of a class of selective anti-CHIKV agents previously identified in our research group, different modifications to this scaffold were rationally designed, and 69 novel small-molecule derivatives were synthesised and evaluated for their inhibition of Chikungunya virus replication in Vero cells. Further structure-activity relationships associated with this class of antiviral agents were elucidated for the original scaffolds, and novel antiviral compounds with EC₅₀ values in the low micromolar range were identified. This work provides the foundation for further investigation of these new structures as antivirals against Chikungunya virus.

Design, synthesis and evaluation against Chikungunya virus of novel small-molecule antiviral agents

Chikungunya virus is a re-emerging arbovirus transmitted to humans by mosquitoes, responsible for an acute flu-like illness associated with debilitating arthralgia, which can persist for several months or become chronic. In recent years, this viral infection has spread worldwide with a previously unknown virulence. To date, no specific antivirals treatments nor vaccines are available against this important pathogen. Starting from the structures of two antiviral hits previously identified in our research group with in silico techniques, this work describes the design and preparation of 31 novel structural analogues, with which different pharmacophoric features of the two hits have been explored and correlated with the inhibition of Chikungunya virus replication in cells. Structure-activity relationships were elucidated for the original scaffolds, and different novel antiviral compounds with EC₅₀ values in the low micromolar range were identified. This work provides the foundation for further investigation of these promising novel structures as antiviral agents against Chikungunya virus.

Synthesis and Pharmacologic Evaluation of Some Benzimidazole Acetohydrazide Derivatives as EGFR Inhibitors

Objectives

In this study, some novel 2-(2-phenyl)-1H-benzo[d]imidazol-1-yl)-N'-(arylmethylene) acetohydrazide derivatives (1-12) were designed and synthesized.

Materials and Methods

Compounds 1-12 were obtained by condensing 2-(2-phenyl)-1H-benzo[d]imidazol-1-yl)acetohydrazide (III) with the corresponding aromatic aldehyde derivatives in the presence of catalytic amounts of hydrochloric acid in ethanol.

Results

Following the structure elucidation, epidermal growth factor receptor kinase inhibitor activity was measured. The ADP-Glo^TM kinase assay determines kinase activity based on the quantification of the amount of ADP produced during a kinase reaction.

Conclusion

Almost all of the compounds' kinase inhibitor activities were rather limited.

Desing and synthesis of potent anti-Trypanosoma cruzi agents new thiazoles derivatives which induce apoptotic parasite death

Chagas disease, caused by the kinetoplastid protozoan parasite Trypanosoma cruzi, remains a relevant cause of illness and premature death and it is estimated that 6 million to 7 million people are infected worldwide. Although chemotherapy options are limited presenting serious problems, such as low efficacy and high toxicity. T. cruzi is susceptible to thiazoles, making this class of compounds appealing for drug development. Previously, thiazoles resulted in an increase in anti-T. cruzi activity in comparison to thiosemicarbazones. Here, we report the structural planning, synthesis and anti-T. cruzi evaluation of new thiazoles derivatives (3a-m and 4a-m), designed from molecular hybridization associated with non-classical bioisosterism. By varying substituents attached to the phenyl and thiazole rings, substituents were observed to retain, enhance or greatly increase their anti-T. cruzi activity, in comparison to the corresponding thiosemicarbazones. In most cases, electron-withdrawing substituents, such as bromine, 3,4-dichloro and nitro groups, greatly increased antiparasitic activity. Specifically, new thiazoles were identified that inhibit the epimastigote proliferation and were toxic for trypomastigotes without affecting macrophages viability. These compounds were also evaluated against cruzain. However, inhibition of this enzyme was not observed, suggesting that the compounds work through another mechanism. In addition, examination of T. cruzi cell death showed that these molecules induce apoptosis. In conclusion, except for compounds 3h and 3k, all thiazoles derivatives evaluated exhibited higher cytotoxic activity against the trypomastigote forms than the reference medicament benznidazole, without affecting macrophages viability. Compounds 4d and 4k were highlights, CC50 = 1.2 e 1.6 μM, respectively. Mechanistically, these compounds do not inhibit the cruzain, but induce T. cruzi cell death by an apoptotic process, being considered a good starting point for the development of new anti-Chagas drug candidates.

Design and synthesis of a new series of 3,5-disubstituted isoxazoles active against Trypanosoma cruzi and Leishmania amazonensis

Chagas disease and leishmaniasis are neglected tropical diseases (NTDs) endemic in developing countries. Although there are drugs available for their treatment, efforts on finding new efficacious therapies are continuous. The natural lignans grandisin (1) and veraguensin (2) show activity against trypomastigote T. cruzi and their scaffold has been used as inspiration to design new derivatives with improved potency and chemical properties. We describe here the planning and microwave-irradiated synthesis of 26 isoxazole derivatives based on the structure of the lignans 1 and 2. In addition, the in vitro evaluation against culture trypomastigotes and intracellular amastigotes of T. cruzi and intracellular amastigotes of L. amazonensis and L. infantum is reported. Among the synthesized derivatives, compounds 17 (IC₅₀ = 5.26 μM for T. cruzi), 29 (IC₅₀ = 1.74 μM for T. cruzi) and 31 (IC₅₀ = 1.13 μM for T. cruzi and IC₅₀ = 5.08 μM for L. amazonensis) were the most active and were also evaluated against recombinant trypanothione reductase of T. cruzi in a preliminary study of their mechanism of action.

Biological and quantitative-SAR evaluations, and docking studies of (E)-N -benzylidenebenzohydrazide analogues as potential antibacterial agents

A series of 15 (E)-N'-benzylidenebenzohydrazide analogues were evaluated for their antimicrobial activities against eleven pathogenic and food-borne microbes, namely, S. aureus (G(+)), L. monocytogenes (G(+)), B. subtilis (G(+)), K. pneumonia (G¯), C. sakazakii (G¯), C. freundii (G¯), S. enterica (G¯), S. enteritidis (G¯), E. coli (G¯), Y. pestis (G¯), and P. aeruginosa (G¯). Most of the compounds exhibited selective activity against some Gram-negative bacterial strains. Of the compounds tested (3a-o), 3b and 3g were most active against C. freundii (MIC = ~19 µg mL(-1)). Whereas, compounds 3d, 3i, 3k and 3n exhibited MIC values ranging from 37.5 to 75 μg mL(-1) against C. freundii, and compounds 3e, 3l and 3n had MIC values of ~75 μg mL(-1) against K. pneumonia. Quantitative structure-antibacterial activity relationships were studied using physicochemical parameters and a good correlation was found between calculated octanol-water partition coefficients (clogP; a lipophilic parameter) and antibacterial activities. In silico screening was also performed by docking high (3b and 3g) and low (3n) activity compounds on the active site of E. coli FabH receptor, which is an important therapeutic target. The findings of these in silico screening studies provide a theoretical basis for the design and synthesis of novel benzylidenebenzohydrazide analogues that inhibit bacterial FabH.

Synthesis of newer 1,2,3-triazole linked chalcone and flavone hybrid compounds and evaluation of their antimicrobial and cytotoxic activities

The present study was carried out in an attempt to synthesize a new class of antimicrobial and antiplasmodial agents by copper catalyzed click chemistry to afford 25 compounds 10-14(a-e) of 1,4-disubstituted-1,2,3-triazole derivatives of chalcones and flavones. The structures of the newly synthesized compounds were established by elemental analysis, IR, (1)H NMR, (13)C NMR and Mass spectral data. The newly synthesized compounds were evaluated for their antibacterial activity against Gram positive bacteria (Staphylococcus aureus, Enterococcus faecalis), Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Shigella boydii, Klebsiella pneumoniae) and antifungal activity against (Candida albicans, Candida tropicalis, Candida parapsilosis, Cryptococcus neoformans, Dermatophyte) as well as molds (Aspergillus niger, Aspergillus fumigatus). The antiplasmodial and cytotoxic activities of these compounds were also evaluated against human malaria parasite Plasmodium falciparum strain 3D7 and human hepato-cellular carcinoma cells (Huh-7), respectively. Compounds 10a, 10c, 10d, 12c and 14e showed promising antibacterial activity while compounds 10e, 11d, 11e, 12c, 13a, 13b, 13e, 14a and 14d showed good antifungal activity as compared to the corresponding standard drugs. Compound 10b was found to be the most active against Plasmodium falciparum while the remaining compounds showed moderate to weak antiplasmodial activity. However, cytotoxic activities of all compounds were found ineffective against Huh-7 cells.

Crystal structures of 2-[5-nitrothien-2-yl)- CH=N–NR–CO(CH2)n]thiophene compounds (R = H or Me; n = 0 or 1)

The crystal structures of four acylhydrazonyl derivatives of thiophene, 2-(ArCH=N–NHCO)- thiophene, (1a), 2-(ArCH=N–NMeCO)-thiophene, (2a), 2-(ArCH=N–NHCOCH2)-thiophene, (3a) and 2-(ArCH= N–NMeCOCH2)-thiophene, (4a) [in each case Ar= 5-nitrothien-2-yl] are reported. The molecular conformations of 1a and 2a are near planar, while those of 3a and 4a exhibit bends at the methylene carbon. Methylations at the hydrazonyl groups in 1a and 3a, to give 2a and 4a, do not result in any significant changes in the molecular conformations. Each of the four molecular conformations possesses a Z C(O)NR/E (C = N) arrangement about the C(O)–NR–N=C(H, aryl) fragment (R=H or Me). The dominant intermolecular interactions in 1a and 3a are N–H···O(carbonyl) hydrogen bonds, with other intermolecular interactions being weaker interactions: C–H···O and N–O···π in 1a and C–H···X (X=O, S, π) and π–π interactions in 3a. In the N-methylated compounds, the intermolecular interactions are restricted to weaker C–H···O hydrogen bonds in 2a and C–H···X (X=O or π) interactions in 4a.