Synthesis and characterization of new inhibitors of cholinesterases based on N-phenylcarbamates: In vitro study of inhibitory effect,type of inhibition,lipophilicity and molecular docking

Based on current treatment of Alzheimer's disease, where the carbamate inhibitor Rivastigmine is used, two series of carbamate derivatives were prepared: (i) N-phenylcarbamates with additional carbamate group (1–12) and (ii) N-phenylcarbamates with monosaccharide moiety (13–24). All compounds were tested for the inhibitory effect on both of the cholinesterases, electric eel acetylcholinesterase (eeAChE) and butyrylcholinesterase from equine serum (eqBChE) and the inhibitory activity (expressed as IC₅₀ values) was compared with that of the established drugs Galanthamine and Rivastigmine. The compounds with two carbamate groups 1–12 revealed higher inhibitory efficiency on both cholinesterases in compared with monosaccharide derived carbamates 13–24 and with Rivastigmine. The significant decrease of inhibitory efficiency on eqBChE (also for eeAChE but in less manner) was observed after deacetalization of monosaccharide. Moreover, the type of inhibitory mechanism of five chosen compounds was studied. It was found, that compounds with two carbamate groups act presumably via a mixed inhibitory mechanism and the compounds with monosaccharide moiety act as non-competitive inhibitors. The lipophilicity of tested compounds was determined using partition coefficient. Specific positions of the inhibitors in the binding sites of cholinesterases were determined using molecular modeling and the results indicate the importance of phenylcarbamate orientation in the catalytic gorges of both enzymes.     

New coumarin derivatives: Design,synthesis and use as inhibitors of hMAO

A series new 2H-chromene-3-carboxamides (4a–4i) and S-2H-chromene-3-carbothioates (5j–5t) were synthesized and evaluated as monoamine oxidase A and B inhibitors. Among them, compound 5k (IC₅₀ = 0.21 μM, IC_{50 iproniazid} = 7.65 μM) showed the most activity and higher MAO-B selectivity (189.2-fold vs 1-fold) with respect to the MAO-A isoform. The need to clarify at a 3D level some important molecular aspects of discussed SAR, we undertaked a number of docking simulations to better assess. The steric effect was analyzed interms of both posing and scoring by investigating the nature of the binding interactions. The docking results of active compound 5k with hMAO-B complex indicated that conserved residue ILE 199 was important for ligand binding via Sigma–Pi interaction.     

Design,synthesis and optimization of bis-amide derivatives as CSF1R inhibitors

Signaling via the receptor tyrosine kinase CSF1R is thought to play an important role in recruitment and differentiation of tumor-associated macrophages (TAMs). TAMs play pro-tumorigenic roles, including the suppression of anti-tumor immune response, promotion of angiogenesis and tumor cell metastasis. Because of the role of this signaling pathway in the tumor microenvironment, several small molecule CSF1R kinase inhibitors are undergoing clinical evaluation for cancer therapy, either as a single agent or in combination with other cancer therapies, including immune checkpoint inhibitors. Herein we describe our lead optimization effort that resulted in the identification of a potent, cellular active and orally bioavailable bis-amide CSF1R inhibitor. Docking and biochemical analysis allowed the removal of a metabolically labile and poorly permeable methyl piperazine group from an early lead compound. Optimization led to improved metabolic stability and Caco2 permeability, which in turn resulted in good oral bioavailability in mice.     

Design,synthesis, and biological evaluation of pyrazole derivatives containing acetamide bond as potential BRAFV600E inhibitors

With the increasingly acquired resistance, relapse and side effects of known marketed BRAF^V600E inhibitors, it’s significant to design the more effective and novel drugs. In this study, a series of novel pyrazole derivatives containing acetamide bond had been designed and synthesized on the basis of analysis of the endogenous ligands extracted from the known B-Raf co-crystals in the PDB database. Then, the compounds were evaluated for biological activities as potential BRAF^V600E inhibitors. The bioassay results in vitro against three human tumor cell lines revealed that some of the compounds showed very impressed antiproliferative property. Among them, the compound 5r with IC₅₀ values of 0.10?±?0.01?μM against BRAF^V600E and 0.96?±?0.10?μM against A375 cell line, showed the most potent inhibitory effect, compared with the positive-controlled agents vemurafenib (IC₅₀?=?0.04?±?0.004?μM for BRAF^V600E, IC₅₀?=?1.05?±?0.10?μM against A375). Further investigation confirmed that the compound 5r could induce A375 cell apoptosis, induce A375 cell death through changing mitochondrial membrane potential, and result in A375 cell arrest at the G1 phase of the cell cycle. Docking simulations results indicated that the compound 5r could bind tightly at the BRAF^V600E active site. Meanwhile, 3D-QSAR model suggested that these compounds may be potential anticancer inhibitors. Overall, the article provided some new molecular scaffolds for the further BRAF^V600E inhibitors.     

Five-membered heteroaromatic ring fused-pyrimidine derivatives: Design,synthesis, and hedgehog signaling pathway inhibition study

A series of novel five-membered heteroaromatic ring fused-pyrimidine derivatives including purines, pyrrolo[2,3-d]pyrimidines, pyrrolo[3,2-d]pyrimidines, thieno[2,3-d]pyrimidines, thieno[3,2-d]pyrimidines and furo[3,2-d]pyrimidines have been identified to be potent inhibitors of hedgehog signaling pathway. The synthesis and SAR of these compounds are described. Among this new series of hedgehog signaling pathway inhibitors, most compounds exhibited significant inhibitory activity compared to vismodegib, indicating that the five-membered heteroaromatic ring fused-pyrimidines stand out as encouraging scaffolds among the currently reported structural skeletons for hedgehog signaling pathway inhibitors, deserving more exploration and further investigation.     

Design,synthesis and biological evaluation of lazabemide derivatives as inhibitors of monoamine oxidase

In the studied a series novel of lazabemide derivatives were designed, synthesized and evaluated as inhibitors of monoamine oxidase (MAO-A or MAO-B). These compounds used lazabemide as the lead compound, and the chemistry structures were modified by used the bioisostere and modification of compound with alkyl principle. The two types of inhibitors (inhibition of MAO-A and inhibition of MAO-B) were screened by inhibition activity of MAO. In vitro experiments showed that compounds 3a, 3d and 3f had intensity inhibition the biological activity of MAO-A, while compounds 3i and 3m had intensity inhibition the biological activity of MAO-B. It could be seen from the data of inhibition activity experiments in vitro, that the compound 3d was IC₅₀?=?3.12?±?0.05?μmol/mL of MAO-A and compound 3m was IC₅₀?=?5.04?±?0.06?μmol/mL. In vivo inhibition activity experiments were conducted to evaluate the inhibitory activity of compounds 3a, 3d, 3f, 3i and 3m by detecting the contents of 5-HT, NE, DA and activity of MAO-A and MAO-B in plasma and brain tissue. In vivo inhibition activity evaluation results showed that the compounds 3a, 3d, 3f, 3i and 3m had increased the contents of 5-HT, NE and DA in plasma and brain tissues. Meanwhile, the determination results activity of MAO in plasma and brain tissue showed that the compounds 3a, 3d, and 3f had a significant inhibitory effect on the activity of MAO-A, while the compounds 3i and 3m showed inhibitory effect on the activity of MAO-B. This study provided a new inhibitors for inhibiting of MAO activity.     

Design,synthesis, cholinesterase inhibition and molecular modelling study of novel tacrine hybrids with carbohydrate derivatives

A series of hybrids containing tacrine linked to carbohydrate-based moieties, such as d-xylose, d-ribose, and d-galactose derivatives, were synthesized by the nucleophilic substitution between 9-aminoalkylamino-1,2,3,4-tetrahydroacridines and the corresponding sugar-based tosylates. All compounds were found to be potent inhibitors of both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in the nanomolar IC₅₀ scale. Most of the d-xylose derivatives (6a-e) were selective for AChE and the compound 6e (IC₅₀?=?2.2?nM for AChE and 4.93?nM for BuChE) was the most active compound for both enzymes. The d-galactose derivative 8a was the most selective for AChE exhibiting an IC₅₀ ratio of 7.6 for AChE over BuChE. Only two compounds showed a preference for BuChE, namely 7a (d-ribose derivative) and 6b (d-xylose derivative). Molecular docking studies indicated that the inhibitors are capable of interacting with the entire binding cavity and the main contribution of the linker is to enable the most favorable positioning of the two moieties with CAS, PAS, and hydrophobic pocket to provide optimal interactions with the binding cavity. This finding is reinforced by the fact that there is no linear correlation between the linker size and the observed binding affinities. The majority of the new hybrids synthesized in this work do not violate the Lipinski's rule-of-five according to FAF-Drugs4, and do not demonstrated predicted hepatotoxicity according ProTox-II.     

Design,synthesis and preliminary biological evaluation of 4-aminopyrazole derivatives as novel and potent JAKs inhibitors

JAKs inhibitors were widely applied in the treatment of immunodeficiency diseases, inflammation and cancers. We designed and synthesized a novel series of 4-aminopyrazole derivatives, which showed inhibitory potency against various JAKs. The in vitro protein kinase inhibition experiment indicated that compounds 17k, 17l, 17m and 17n could inhibit JAKs effectively. Among them, compound 17m possessed the highest protein kinase inhibitory rates (%) at 10 μM, which were 97, 96 and 100 to JAK1, JAK2 and JAK3, respectively. Further evaluation revealed that the IC₅₀ values of 17m against JAK1, JAK2 and JAK3 were 0.67 μM, 0.098 μM and 0.039 μM, respectively. Moreover, western blotting results showed compound 17m could inhibit the phosphorylation of JAK2 in Hela cells effectively. The data supports the further investigation of these compounds as novel JAKs inhibitors.     

Design,synthesis and biological evaluation of benzyloxyphenyl-methylaminophenol derivatives as STAT3 signaling pathway inhibitors

STAT3 signaling pathway has been validated as a vital therapeutic target for cancer therapy. Based on the novel STAT3 inhibitor of a benzyloxyphenyl-methylaminophenol scaffold hit (1) discovered through virtual screening, a series of analogues had been designed and synthesized for more potent inhibitors. The preliminary SAR had been discussed and the unique binding site in SH2 domain was predicted by molecular docking. Among them, compounds 4a and 4b exhibited superior activities than hit compound (1) against IL-6/STAT3 signaling pathway with IC₅₀ values as low as 7.71 μM and 1.38 μM, respectively. Compound 4a also displayed potent antiproliferative activity against MDA-MB-468 cell line with an IC₅₀ value of 9.61 μM. We believe that these benzyloxyphenyl-methylaminophenol derivatives represent a unique mechanism for interrogating STAT3 as well as a potential structure type for further exploration.     

Design,synthesis, and evaluation of pyrrolo[2,1-f][1,2,4]triazine derivatives as novel hedgehog signaling pathway inhibitors

A novel series of Hh signaling pathway inhibitors were designed by replacing the pyrimidine skeleton of our earlier reported lead compound 1 with pyrrolo[2,1-f][1,2,4]triazine scaffold. Starting from this new scaffold, SAR exploration was investigated based on structural modification on A-ring, C-ring and D-ring. And several much potent compounds were studies in vivo to profile their pharmacokinetic properties. Finally, optimization leads to the identification of compound 19a, a potent Hh signaling pathway inhibitor with superior potency in vitro and satisfactory pharmacokinetic properties in vivo.     

Synthesis,biological evaluation and docking studies of 2,3-dihydroquinazolin-4(1H)-one derivatives as inhibitors of cholinesterases

In search of potent inhibitors of cholinesterases, we have synthesized and evaluate a number of 2,3-dihydroquinazolin-4(1H)-one derivatives. The synthetic approach provided an efficient synthesis of the target molecules with excellent yield. All the tested compounds showed activity against both the enzymes in micromolar range. In many case, the inhibition of both enzymes are higher than or comparable to the standard drug galatamine. With the selectivity index of 2.3 for AChE, compound 5f can be considered as a potential lead compound with a feature of dual AChE/BChE inhibition with IC₅₀ = 1.6 ± 0.10 μM (AChE) and 3.7 ± 0.18 μM (BChE). Binding modes of the synthesized compounds were explored by using GOLD (Genetic Optimization for Ligand Docking) suit v5.4.1. The computed binding modes of these compounds in the active site of AChE and BChE provide an insight into the mechanism of inhibition of these two enzyme.     

Design,synthesis and biological evaluation of 4-aryl-5-aminoalkyl-thiazole-2-amines derivatives as ROCK II inhibitors

A series of 4-aryl-5-aminoalkyl-thiazole-2-amines were designed and synthesized, and their inhibitory activity on ROCK II was screened by enzyme-linked immunosorbent assay (ELISA). The results showed that 4-aryl-5-aminomethyl-thiazole-2-amines derivatives had certain ROCK II inhibitory activities. Compound 10l showed ROCK II inhibitory activity with IC₅₀ value of 20 nM.     

Design, synthesis, and activity of caffeoyl pyrrolidine derivatives as potential gelatinase inhibitors

The synthesis and biological evaluation of caffonyl pyrrolidine derivatives as MMPs inhibitors are reported in this paper. Inhibiting activities of synthesized compounds on gelatinase (MMP-2 and -9) were tested by using succinylated gelatin as substrate. Structure-activity relationship results from these tested compounds demonstrated that longer and more flexible side chain linked to the pyrrolidine ring at C(4) produced higher activity at gelatinase. Furthermore, aromatic heterocycle and sulfamide in the same position could enhance the activities. Compounds with free phenol hydroxyl group showed higher activity compared to methylated derivatives (or counterparts), which confirms the importance of phenol hydroxyl functionality in the interaction with gelatinase. The anti-metastasis model of mice bearing H(22) tumor cell was used to evaluate their in vivo inhibiting activities. All tested compounds were orally administered at a dose of 50 or 100mg/kg, 6days/week for two weeks. The test results demonstrated that most of these inhibitors showed significant anti-cancer activities (inhibitory rate>35%) and were devoid of toxic effects. Compound 29 showed the highest inhibitory rate at 69.25%, indicating that it might be a promising lead compound.     

Design, synthesis, and biological evaluation of novel water-soluble N-mustards as potential anticancer agents

A series of novel water-soluble N-mustard-benzene conjugates bearing a urea linker were synthesized. The benzene moiety contains various hydrophilic side chains are linked to the meta- or para-position of the urea linker via a carboxamide or an ether linkage. The preliminary antitumor studies revealed that these agents exhibited potent cytotoxicity in vitro and therapeutic efficacy against human tumor xenografts in vivo. Remarkably, complete tumor remission in nude mice bearing human breast carcinoma MX-1 xenograft and significant suppression against prostate adenocarcinoma PC3 xenograft were achieved by treating with compound 9aa′ at the maximum tolerable dose with relatively low toxicity. We also demonstrate that the newly synthesized compounds are able to induce DNA cross-linking through alkaline agarose gel shift assay. A pharmacokinetic profile of the representative 9aa′ in rats was also investigated. The current studies suggest that this agent is a promising candidate for preclinical studies.     

Synthesis,crystal structure determination,biological screening and docking studies of N1-substituted derivatives of 2,3-dihydroquinazolin-4(1H)-one as inhibitors of cholinesterases

Pursuing the strategy of developing potent AChE inhibitors, we attempted to carry out the N¹-substitution of 2,3-dihydroquinazolin-4(1H)-one core. A set of 32 N-alkylated/benzylated quinazoline derivatives were synthesized, characterized and evaluated for their inhibition against cholinesterases. N-alkylation of the series of the compounds reported previously (N-unsubstituted) resulted in improved activity. All the compounds showed inhibition of both enzymes in the micromolar to submicromolar range. Structure activity relationship (SAR) of the 32 derivatives showed that N-benzylated compounds possess good activity than N-alkylated compounds. N-benzylated compounds 2ad and 2af were found very active with their IC₅₀ values toward AChE in submicromolar range (0.8 µM and 0.6 µM respectively). Binding modes of the synthesized compounds were explored by using GOLD (Genetic Optimization for Ligand Docking) suit v5.4.1. Computational predictions of ADMET studies reveal that all the compounds have good pharmacokinetic properties with no AMES toxicity and carcinogenicity. Moreover, all the compounds are predicted to be absorbed in human intestine and also have the ability to cross blood brain barrier. Overall, the synthesized compounds have established a structural foundation for the design of new inhibitors of cholinesterase.     

Design, synthesis, and biological evaluation of substituted hydrazone and pyrazole derivatives as selective COX-2 inhibitors: Molecular docking study

New arylhydrazone derivatives and a series of 1,5-diphenyl pyrazoles were designed and synthesized from 1-(4-chlorophenyl)-4,4,4-trifuorobutane-1,3-dione 1. The newly synthesized compounds were investigated in vivo for their anti-inflammatory activities using carrageenan-induced rat paw oedema model. Moreover, they were tested for their inhibitory activity against ovine COX-1 and COX-2 using an in vitro cyclooxygenase (COX) inhibition assay. Some of the new compounds (2f, 6a and 6d) showed a reasonable in vitro COX-2 inhibitory activity, with IC?? value of 0.45 μM and selectivity index of 111.1. A virtual screening was carried out through docking the designed compounds into the COX-2 binding site to predict if these compounds have analogous binding mode to the COX-2 inhibitors. Docking study of the synthesized compounds 2f, 6a and 6d into the active site of COX-2 revealed a similar binding mode to SC-558, a selective COX-2 inhibitor.     

Design,synthesis and in vitro evaluation of novel derivatives as serotonin N-acetyltransferase inhibitors

Serotonin N-acetyltransferase (arylalkylamine N-acetyl-transferase, AANAT) is an enzyme that catalyses the first rate limiting step in the biosynthesis of melatonin (5-methoxy-N-acetyltryptamine). Different physiopathological disorders in human may be due to abnormal secretion of melatonin leading to an inappropriate exposure of melatonin receptors to melatonin. For that reason, we have designed, synthesized and evaluated as inhibitors of human serotonin N-acetyltransferase, a series of compounds that were able to react with coenzyme A to give a bisubstrate analog inhibitor. Compound 12d was found to be a potent AANAT inhibitor (IC50 = 0.18 microM).     

Design,synthesis and biological activity of novel substituted 3-benzoic acid derivatives as MtDHFR inhibitors

The enzyme dihydrofolate reductase from M. tuberculosis (MtDHFR) has a high unexploited potential to be a target for new drugs against tuberculosis (TB), due to its importance for pathogen survival. Preliminary studies have obtained fragment-like molecules with low affinity to MtDHFR which can potentially become lead compounds. Taking this into account, the fragment MB872 was used as a prototype for analogue development by bioisosterism/retro-bioisosterism, which resulted in 20 new substituted 3-benzoic acid derivatives. Compounds were active against MtDHFR, with IC₅₀ values ranging from 7 to 40 μM, where compound 4e not only had the best inhibitory activity (IC₅₀ = 7 μM), but also was 71-fold more active than the original fragment MB872. The 4e inhibition kinetics indicated an uncompetitive mechanism, which was supported by molecular modeling which suggested that the compounds can access an independent backpocket from the substrate and competitive inhibitors. Thus, based on these results, substituted 3-benzoic acid derivatives have strong potential to be developed as novel MtDHFR inhibitors and also anti-TB agents.     

Design,synthesis and biological evaluation of new Myo-inositol derivatives as potential RAS inhibitors

Ras is a small family of GTPases that control numerous cellular functions like cell proliferation, growth, survival, gene expression, and is closely engaged in cancer pathogenesis. The ras-targeted methodology entails a holy grail in oncology. Nevertheless, there are no specific molecules reported targeting the same, although it is a known oncogene for more than three decades. In this study, we have designed and synthesized new phosphate derivatives of Myo-inositol to inhibit the oncogenic KRAS pathway in breast cancer cells, which has been validated by cellular and theoretical studies. The synthesized compound 1b (C2-O-phosphate derivative of Myo-inositol 1,3,5-orthobenzoate) inhibited the downstream signaling pathway of oncogenic KRAS, RAF/MEK/ERK. Furthermore, we also found that this compound induced necrosis/apoptosis and causes cell cycle arrest. This class of molecules may work as a potential inhibitor of breast cancer caused by a mutation in KRAS and its downstream proteins. Though the efficacy of the molecules is in the micromolar scale, they have not been explored previously for RAS inhibition. Impressive preliminary results are presented in this article which could be further explored for its detailed biological studies to get better candidates as RAS inhibitors.     

Xanthone derivatives as phosphoglycerate mutase 1 inhibitors: Design,synthesis, and biological evaluation

Phosphoglycerate mutase 1 (PGAM1) is a glycolytic enzyme that dynamically converts 3-phosphoglycerate (3PG) to 2-phosphoglycerate (2PG), which was upregulated to coordinate glycolysis, pentose phosphate pathway (PPP) and serine biosynthesis to promote cancer cell proliferation and tumor growth in a variety of cancers. However, only a few inhibitors of PGAM1 have been reported with poor molecular or cellular efficacy. In this paper, a series of xanthone derivatives were discovered as novel PGAM1 inhibitors through scaffold hopping and sulfonamide reversal strategy based on the lead compound PGMI-004A. Most xanthone derivatives showed higher potency against PGAM1 than PGMI-004A and exhibited moderate anti-proliferation activity on different cancer cell lines.