Structure and activity relationship of 2-(substituted benzoyl)-hydroxyindoles as novel CaMKII inhibitors

A series of novel 2-substituted-5-hydroxyindoles were synthesized and evaluated for their inhibitory activity against CaMKII. Structure and activity relationship results indicated that potent inhibitory activity could be achieved by modification at the para-position of the phenyl ring of the high throughput screening hit compound 2. Among the prepared compounds, we identified 14 as a novel CaMKII inhibitor with an activity stronger than that of KN-93, a known CaMKII inhibitor.     

Synthesis and structure based optimization of 2-(4-phenoxybenzoyl)-5-hydroxyindole as a novel CaMKII inhibitor

Based on 2-(4-phenoxybenzoyl)-5-hydroxyindole (2), a novel structural class of CaMKII inhibitors were synthesized and further optimized. The strong acidity of the hydroxyl group and the lipophilic group at the 4 and 6-positions were found to be necessary for strong CaMKII inhibition. Compound 25 was identified as a promising compound with 50-fold more potent inhibitory activity for CaMKII than 2. Compound 25 also showed high selectivity for CaMKII over off-target kinases.     

Synthesis and evaluation of naphthoflavones as a new class of non purine xanthine oxidase inhibitors

In view of reported xanthine oxidase inhibitory potential of naphthopyrans and flavones, naphthoflavones as hybrids of the two were designed, synthesized and evaluated for in vitro xanthine oxidase inhibitory activity in the present study. The results of the assay revealed that the naphthoflavones possess promising inhibitory potential against the enzyme with IC₅₀ values ranging from 0.62 to 41.2 μM. Structure activity relationship indicated that the nature and placement of substituents on the phenyl ring at 2nd position remarkably influences the inhibitory activity. Substitution of halo and nitro groups at ortho and para position of the phenyl ring (2nd position) remarkably favored the activity. NF-4 with p-fluoro phenyl ring was the most potent inhibitor with IC₅₀ value of 0.62 μM. Enzyme kinetics study was also performed to investigate the inhibition mechanism and it was found that the naphthoflavones displayed mixed type inhibition. The basis of significant inhibition of xanthine oxidase by NF-4 was rationalized by molecular modeling studies.     

Selective cyclooxygenase inhibition and ulcerogenic liability of some newly prepared anti-inflammatory agents having thiazolo[4,5-d]pyrimidine scaffold

Novel candidates of thiazolo[4,5-d]pyrimidines (9a-l) were synthesized and their structures were elucidated by spectral and elemental analyses. All the novel derivatives were screened for their cyclooxygenase inhibitory effect, anti-inflammatory activity and ulcerogenic liability. All the new compounds exhibited anti-inflammatory activity, especially 1-(4-[7-(4-nitrophenyl)-5-thioxo-5,6-dihydro-3H-thiazolo[4,5-d]pyrimidin-2-ylideneamino]phenyl)ethanone (9g) was the most active derivative with 57%, 88% and 88% inhibition of inflammation after 1, 3 and 5h, respectively. Furthermore, this derivative 9g recorded higher anti-inflammatory activity than celecoxib which showed 43%, 43% and 54% inhibition after 1, 3 and 5h, sequentially. Moreover, the target derivatives 9a-l demonstrated moderate to high potent inhibitory action towards COX-2 (IC₅₀ = 0.87–3.78 µM), in particular, the derivatives 9e (IC₅₀ = 0.92 µM), 9g (IC₅₀ = 0.87 µM) and 9k (IC₅₀ = 1.02 µM) recorded higher COX-2 inhibitory effect than the selective COX-2 inhibitor drug celecoxib (IC₅₀ = 1.11 µM). The in vivo potent compounds (9e, 9g and 9k) caused variable ulceration effect (ulcer index = 5–12.25) in comparison to that of celecoxib (ulcer index = 3). Molecular docking was performed to the most potent COX-2 inhibitors (9e, 9g and 9k) to explore the binding mode of these derivatives with Cyclooxygenase-2 enzyme.     

Novel synthesized SLC-0111 thiazole and thiadiazole analogues: Determination of their carbonic anhydrase inhibitory activity and molecular modeling studies

In the presented work, we report the design and synthesis of novel SLC-0111 thiazole and thiadiazole analogues (11a–d, 12a–d, 16a–c and 17a–d). A bioisosteric replacement approach was adopted to replace the 4-fluorophenyl tail of SLC-0111 with thiazole and thiadiazole ones, which were thereafter extended with lipophilic un/substituted phenyl moieties. All the newly synthesized SLC-0111 analogues were evaluated in vitro for their inhibitory activity towards a panel of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) isoforms (hCA I, II, IX and XII), using a stopped-flow CO₂ hydrase assay. All the examined isoforms were inhibited by the primary sulfonamide derivatives (11a–d and 12a–d) in variable degrees with the following K_I ranges: 162.6–7136 nM for hCA I, 9.0–833.6 nM for hCA II, 7.9–153.0 nM for hCA IX, and 9.4–94.0 nM for hCA XII. In particular, compounds 12b and 12d displayed 5.5-fold more potent inhibitory activity (K_Is = 8.3 and 7.9 nM, respectively) than SLC-0111 (K_I = 45 nM) towards hCA IX. Molecular docking study was carried out for 12d within the hCA IX (PDB 3IAI) active site, to justify its inhibitory activity.     

Structure-Plant Phytotoxic Activity Relationship of 7,7′-epoxylignanes, (+)- and (−)-verrucosin: Simplification on the aromatic ring substituents

The synthesized 7-aryl derivatives of (7R,7′S,8S,8′S)-(+)-verrucosin were applied to growth inhibitory activity test against ryegrass at 1 mM. 7-(3-Ethoxy-4-hydroxyphenyl) derivative 12 and 7-(2-hydroxyphenyl) derivative 4 showed comparable activity to those of (+)-verrucosin against the root (−95%) and the shoot (−60%), respectively. The growth inhibitory activity test against lettuce using synthesized 7-aryl derivatives of (7S,7′R,8R,8′R)-(−)-verrucosin at 1 mM showed that the activities of 7-(3-hydroxyphenyl) derivative 20 and 7-(3-ethoxy-4-hydroxyphenyl) derivative 28 are similar to that of (−)-verrucosin against the root (−95%). Against the shoot, 7-(3-hydroxyphenyl) derivative 20 showed higher activity (−80%) than that of (−)-verrucosin (−60%). As the next step, (7S,7′R,8R,8′R)-7-(3-hydroxyphenyl)-7′-aryl-(−)-verrucosin derivatives, in which the most effective 3-hydroxyphenyl group is employed as 7-aromatic ring, were synthesized for the assay against lettuce. In this experiment, 7′-(2-hydroxyphenyl) derivative 37 and 7′-(3-hydroxyphenyl) derivative 38 showed similar activity to that of derivative 20. The effect of 7- and 7′-aryl structures of 7,7′-epoxylignanes on the plant growth inhibitory activity was clarified. The 7- and 7′-aryl structures were simplified to show comparable activity to or higher activity than that of (−)-verrucosin. The plant growth inhibitory activity of a nutmeg component, (+)-fragransin C_3b, was estimated as −80% inhibition at 1 mM against ryegrass roots.     

Synthesis of (benzimidazol-2-yl)aniline derivatives as glycogen phosphorylase inhibitors

A series of (benzimidazol-2-yl)-aniline (1) derivatives has been synthesized and evaluated as glycogen phosphorylase (GP) inhibitors. Kinetics studies revealed that compounds displaying a lateral heterocyclic residue with several heteroatoms (series 3 and 5) exhibited modest inhibitory properties with IC₅₀ values in the 400–600 μM range. Arylsulfonyl derivatives 7 (Ar: phenyl) and 9 (Ar: o-nitrophenyl) of 1 exhibited the highest activity (series 2) among the studied compounds (IC₅₀ 324 μM and 357 μM, respectively) with stronger effect than the p-tolyl analogue 8.     

Design,synthesis and biological evaluation of new 2,3-diarylquinoline derivatives as selective cyclooxygenase-2 inhibitors

A new group of 2,3-diarylquinoline derivatives possessing a methylsulfonyl COX-2 pharmacophore at the para-position of the C-2 phenyl ring were synthesized and evaluated as selective COX-2 inhibitors. In vitro COX-1/COX-2 structure–activity relationships were determined by varying the substituents on the C-4 quinoline ring. Among the 2,3-diarylquinolines, 2-(4-(methylsulfonyl) phenyl)-3-phenylquinoline-4-carboxylic acid (8) exhibited the highest potency and selectivity for COX-2 inhibitory activity (COX-2 IC₅₀ = 0.07 μM; selectivity index = 687.1) that was more selective than the reference drug celecoxib (COX-2 IC₅₀ = 0.06 μM; selectivity index = 405). A molecular modeling study where 8 was docked in the binding site of COX-2 indicated that the p-MeSO₂ COX-2 pharmacophore group on the C-2 phenyl ring is oriented in the vicinity of the COX-2 secondary pocket (Arg⁵¹³, Phe⁵¹⁸ and Val⁵²³) and the carboxylic acid substituent can interact with Ser⁵³⁰. The structure activity data acquired indicate that the size and nature of the C-4 quinoline substituent are important for COX-2 inhibitory activity.     

Synthesis of tricyclic fused coumarin sulfonates and their inhibitory effects on LPS-induced nitric oxide and PGE2 productions in RAW 264.7 macrophages

The regulations of NO and PGE₂ productions are research topics of interest in the field of antiinflammatory drug development. In the present study, a series of tricyclic fused coumarin sulfonate derivatives was synthesized and evaluated for their abilities to inhibit NO and PGE₂ productions in LPS-induced RAW 264.7 macrophages. Among all the target compounds, compound 1g possessing p-(trifluoromethyl)phenyl and fused cycloheptane moieties showed the highest inhibitory effects on NO and PGE₂ productions. Compound 1g not only inhibited COX-2 activity but also reduced expressions of COX-2 and iNOS. Furthermore, ADME profiling showed that compounds 1g, 1j, 1m, and 1n are estimated to be orally bioavailable.     

Synthesis and in vitro biological evaluation of novel coumarin derivatives containing isoxazole moieties on melanin synthesis in B16 cells and inhibition on bacteria

A novel series of coumarin derivatives 6a–o, bearing isoxazole moieties were designed and synthesized. After that, they were evaluated for melanin synthesis in murine B16 cells and inhibitory effect on the growth of CA (Candida albicans), EC (Escherichia coli), SA (Staphylococcus aureus). It was found that eleven compounds (6b–f, 6j–o) showed a better activity on melanin synthesis than positive control (8-MOP). Among them, compounds 6d (242%) and 6f (390%), with nearly 1.6 and 2.6-fold potency compared with 8-MOP (149%) respectively, were recognized as the most promising candidate hits for further pharmacological study of anti-vitiligo.Seven halogen substituted compounds exhibited moderate antimicrobial activity against CA. It is interesting that 6e–f and 6l–m, which had two halogens on the benzene showed a comparable activity with Amphotericin B against CA.The evaluation of melanin synthesis in B16 cells and inhibitory effect on bacteria of above structurally diverse derivatives had also led to an outline of structure-activity relationship.     

Synthesis and anti-Candidal activity of N-(4-aryl/cyclohexyl)-2-(pyridine-4-yl carbonyl) hydrazinecarbothioamide

Eighteen N-(4-aryl/cyclohexyl)-2-(pyridine-4-yl carbonyl) hydrazinecarbothioamide derivatives were synthesized, evaluated against ten clinical isolates of Candida spp. and compared with itraconazole. Introduction of p-chloro (2c), p-iodo (2q), m-chloro (2l) and o-nitro (2r) substitution at phenyl ring of thiosemicarbazide enhanced the anti-Candida activity. Compound (2c) bearing p-cholorophenyl ring was found to be the most effective against Candida albicans ATCC 66027, Candida spp. 12810 (blood) and Candida spp. 178 (HVS) with MIC value of 0.09–0.78 μg/mL, whereas itraconazole exhibits the inhibitory activity with MIC value of 0.04–1.56 μg/mL against all tested strains. There is a correlation between anti-Candidal activity and p-chloro substitution at phenyl ring of thiosemicarbazide. All synthesized compounds were investigated for their potential cytotoxicity against non cancer cell line MCF-10A. The active compounds 2c, 2r and 2a were further investigated for their cytotoxic effects on three cancer cell lines; HT1080 (skin), HepG2 (liver) and A549 (lung). The active compounds showed minimal cytotoxic activity against non cancer cell line and all three cancer cell lines. Moreover, compound 2c displaying better activity against C. albicans ATCC66027 and Candida spp. [blood] compared to reference drug (itraconazole), represents a good lead for the development of newer, potent and broad spectrum anti-Candidal agents.     

MAO inhibitory activity modulation: 3-Phenylcoumarins versus 3-benzoylcoumarins

With the aim of finding the structural features for the human MAO inhibitory activity and selectivity, in the present communication we report the synthesis, pharmacological evaluation and a comparative study of a new series of 3-phenylcoumarins (compounds 1-4) and 3-benzoylcoumarins (compounds 5-8). A bromo atom and a methoxy/hydroxy substituent were introduced in these scaffolds, at six and eight positions of the coumarin moiety, respectively. The synthesized compounds 1-8 were evaluated as MAO-A and B inhibitors using R-(−)-deprenyl and iproniazide as reference compounds. The presence or absence of a carbonyl group between the coumarin and the phenyl substituent in 3 position remarks, respectively, the MAO-A or MAO-B inhibitory activity. Some of the new compounds showed MAO-B inhibitory activities in the low nanomolar range. Compound 2 (IC₅₀ = 1.35 nM) showed higher inhibitory activity than the R-(−)-deprenyl (IC₅₀ = 19.60 nM) and higher MAO-B selectivity, with more than 74,074-fold inhibition level, respecting to the MAO-A isoform.     

Synthesis and biological evaluation of C-glucosides with azulene rings as selective SGLT2 inhibitors for the treatment of type 2 diabetes mellitus: Discovery of YM543

Here, a series of C-glucosides with azulene rings in the aglycon moiety was synthesized and the inhibitory activities toward hSGLT1 and hSGLT2 were evaluated. Starting from the azulene derivative 7 which had relatively good SGLT2 inhibitory activity, compound 8a which has a 3-[(azulen-2-yl)methyl]phenyl group was identified as a lead compound for further optimization. Introduction of a phenolic hydroxyl group onto the central benzene ring afforded a potent and selective SGLT2 inhibitor 8e, which reduced blood glucose levels in a dose-dependent manner in rodent diabetic models. A mono choline salt of 8e (YM543) was selected as a clinical candidate for use in treating type 2 diabetes mellitus.     

Synthesis and biological evaluation of a new series of N-ylides as protein farnesyltransferase inhibitors

A new family of 30 benzoylated N-ylides 4 and 5 was synthesized and evaluated for the inhibitory activity on human protein farnesyltransferase. Most of these novel compounds possessed in vitro inhibition potencies in the micromolar range. The nature of the substituents on the pyridine and phenyl units proved to be important in determining inhibitory activity and generally, the replacement of the cyanoacrylonitrile function by a cyanoethylacrylate group decreased the biological potential on farnesyltransferase. These results completed our SAR study on this original class of N-ylides.     

Design and synthesis of novel quinazolinone-1,2,3-triazole hybrids as new anti-diabetic agents: In vitro α-glucosidase inhibition,kinetic, and docking study

A novel series of quinazolinone-1,2,3-triazole hybrids 10a-p were designed, synthesized, and evaluated for their in vitro α-glucosidase inhibitory activity leading to efficient anti-diabetic agents. All synthesized compounds exhibited good inhibitory activity against yeast α-glucosidase (IC₅₀ values in the range of 181.0–474.5 µM) even much more potent than standard drug acarbose (IC₅₀ = 750.0). Among them, quinazolinone-1,2,3-triazoles possessing 4-bromobenzyl moiety connected to 1,2,3-triazole ring (10g and 10p) demonstrated the most potent inhibitory activity towards α-glucosidase. Compound 10g inhibited α-glucosidase in a competitive manner with K_i value of 117 µM. Furthermore, the binding modes of the most potent compounds 10g and 10p in the α-glucosidase active site was studied through in silico docking studies. Also, lack of cytotoxicity of compounds 10g and 10p was confirmed via MTT assay.     

Synthesis and DNase I inhibitory properties of some 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidines

A series of six novel and six known thieno[2,3-d]pyrimidin-4-amines 2–13 were synthesized, and further were used as a starting material for preparation of a small series of eight novel thieno[2,3-d]pyrimidin-4-phthalimides 14–21. Eight compounds, five amine and three phthalimide derivatives, inhibited bovine pancreatic DNase I with an IC₅₀ below 200 µM, being more effective than referent inhibitor crystal violet. Phthalimide derivatives 16, 18 and 19 exhibited higher DNase I inhibitory activity compared to their amine precursors 7, 10 and 11. Compound 19, as the most potent (IC₅₀ = 106 ± 16 µM), offers a good starting point for a design of new DNase I inhibitors. The Pharma RQSAR model showed a significant enhancement of thieno[2,3-d]pyrimidines activity using aryl substituents at R1 position. The E-State RQSAR model clarified the most important structural fragments relevant for DNase I inhibition. Molecular docking and Site Finder module defined the thieno[2,3-d]pyrimidines interactions with the most important catalytic residues of DNase I, including Glu 39, His 134, Asp 168 and His 252. We also found that steric effects and increase of molecular volume play a vital role in DNase I inhibition.     

Synthesis and biological evaluation of some N-(3-(1H-tetrazol-5-yl) phenyl)acetamide derivatives as novel non-carboxylic PTP1B inhibitors designed through bioisosteric modulation

Described herein is the synthesis and biological evaluation of a series of non-carboxylic inhibitors of Protein Tyrosine Phosphatase 1B designed using bioisosteric replacement strategy. Six N-(3-(1H-tetrazol-5-yl)phenyl)acetamide derivatives designed employing the aforementioned strategy were synthesized and screened for PTP1B inhibitory activity. Among the synthesized compounds, compound NM-03 exhibited the most potent inhibitory activity with IC₅₀ value of 4.48 µM. Docking studies with NM-03 revealed the key interactions with desired amino acids in the binding site of PTP1B. Furthermore, compound NM-03 also elicited good in vivo activity. Taken together, the results of this study establish N-(3-(1H-tetrazole-5-yl)phenyl)-2-(benzo[d]oxazol-2-ylthio)acetamide (NM-03) as a valuable lead molecule with great potential for PTP1B inhibitor development targeting diabetes.     

Tyrosine kinase inhibition effects of novel Pyrazolo[1,5-a]pyrimidines and Pyrido[2,3-d]pyrimidines ligand: Synthesis,biological screening and molecular modeling studies

Tyrosine kinases are one of the most critical mediators in the signaling path way. Late studies have proved the part of tyrosine kinases in the pathophysiology of cancer diseases. This current research paper has focused on investigating the novel Pyrazolo[1,5-a]pyrimidines and Pyrido[2,3-d]pyrimidines as a small molecules that can inhibit tyrosine kinase in cancer cells. NCI protocol was applied to test the antitumor activity of such compounds. Leukemia and renal cancer cell lines proved to be sensitive to some derivatives such as 6b–d, 9a and 11 with GI% values ranging from 30.4 to 41.3%. In addition, compound 11 proved to be the most active against MCF-7 with GI% 62.5. The synthesized compounds were also evaluated for their inhibitory effects against EGFR kinase enzyme. Compound 9b proved to be the most active one among the synthesized series with inhibition % value of 81.72 at 25 nM concentration and IC₅₀ 8.4 nM which is very close to the reference drug Sorafenib. In vitro cytotoxicity test was also performed using the MCF-7 breast cell line. Computer modeling using the active site of tyrosine kinase as a template and the most active tyrosine kinase inhibitors were calculated. Docking studies of the synthesized compounds into the active site of EGFR kinase domain showed good agreement with the obtained biological results.     

Design and synthesis of C10 modified and ring-truncated canthin-6-one analogues as effective membrane-active antibacterial agents

A series of canthin-6-one analogues were designed and synthesized in order to study their antibacterial activity and structure–activity relationships. Compound 22 showed a broad spectrum of antibacterial activity and exhibited better bactericidal effect (8-fold superiority against Staphylococcus aureus and 2-fold superiority against Ralstonia solanacearum) than fosfomycin sodium and propineb with a minimum inhibitory concentration value of 2?μg/mL. Moreover, it showed low cytotoxicity, stimulation on germination rates and good “drug-like” properties. Membrane-active mechanism was further studied by fluorescent microscopy, scanning electron microscopy, cytoplasmic β-galactosidase leakage assay and evaluation of the molecular docking. The results showed that 22 may exert its bactericidal effect by damaging bacterial cell membranes and influencing the membrane formation, both of which could lead to cell death. The in vivo antibacterial assay with a protective efficacy of 68% demonstrated the potential of C ring-truncated canthin-6-one 22 as a new bactericide.     

Evaluation of dihydropyrimidin-(2H)-one analogues and rhodanine derivatives as tyrosinase inhibitors

A series of dihydropyrimidin-(2H)-one analogues and rhodanine derivatives were synthesized and their inhibitory effects on the diphenolase activity of mushroom tyrosinase were evaluated. The results showed that some of the synthesized compounds exhibited significant inhibitory activities. Especially, compound 15 bearing a hydroxyethoxyl group at position-4 of phenyl ring exhibited most potent tyrosinase inhibitory activity with IC₅₀ value of 0.56 mM. The inhibition mechanism analysis of compound 15 demonstrated that the inhibitory effect of the compound on the tyrosinase was irreversible. These results suggested that such compounds might be served as lead compounds for further designing new potential tyrosinase inhibitors.