Novel benzoxazole-based thiosemicarbazide derivatives as new inhibitors of urease and β-Glucuronidase: Synthesis,in vivo anti-nematodal activity and ADMET prediction along with in silico study

Here, we discuss the synthesis of thiosemicarbazide derivatives based on benzoxazole. These compounds were obtained via sequence of reactions. The targeted products were confirmed using a number of spectroscopic methods, including NMR (1H and 13C) and EI-MS. After spectral confirmation all the synthesized compounds were evaluated for urease and β-Glucuronidase inhibitory activity in order to explore their biological significances in the presence of standard drug thiourea (IC₅₀ = 21.86 ± 0.40) and D-saccharic acid 1,4-lactone (IC50 value 22.00 ± 1.10 µM) respectively. Among the evaluated series, compounds 14 and 15 (1.10 and 0.01 and 2.20 and 0.60) were shown to have slightly greater potential than standard drugs. Anti-nematodal activity was also employed to explore the cytotoxic nature of synthesized analogs. In order to establish the binding relationship with enzyme active sites, molecular docking experiments were done and directions for compound modification based on SAR features were addressed. In addition, ADMET prediction study also investigated to found drug like properties of the potential analogs.     

New benzoxazole-based sulphonamide hybrids analogs as potent inhibitors of α-amylase and α-glucosidase: Synthesis and in vitro evaluation along with in silico study

The development of drugs resistance in diabetes mellitus is a growing clinical problem, creates many challenges for patient. To overcome these problems, there is a serious deficiency of anti-diabetic agents, may be synthesized that inhibit alpha amylase and alpha glucosidase activity. Here, we have design and synthesized benzoxazole based sulphonamide derivatives and evaluated for their anti-diabetic activity. Twenty-two benzoxazole based sulphonamide derivatives were synthesized by reacting 2-aminophenol with carbon disulphide in the presence of base (Et3N) to obtained 2-marcapto benzoxazole which was further dissolved in ethanol by slow addition of different substituted phenacyl bromide in the presence of triethylamine, afforded varied S-substituted benzoxazole products. These products were dissolved in ethanol and hydrazine hydrate was added an excess in the presence of acetic acid to gives Schiff base. This Schiff base products were further dissolved in THF along with different substituted benzene sulphonyl chloride followed by addition of few drops of Et3N, yielded benzoxazole based sulphonamide derivatives (1–22). Moreover, SAR was established for the synthesized compounds and molecular docking studies were conducted for the potent moieties in order to explore the binding modalities of analogs. Among the tested series few analogues were found few folds better potential than standard drug but analog 1 (IC₅₀ = 1.10 ± 0.20 µM, 1.20 ± 0.30 µM), showed promising anti-diabetic activity against α-amylase and α-glucosidase (11.12 ± 0.15 µM and 11.29 ± 0.07 µM respectively).     

Identification of novel oxadiazole-based benzothiazole derivatives as potent inhibitors of α-glucosidase and urease: Synthesis,in vitro bio-evaluation and their in silico molecular docking study

This research work represents a synthetic approach for the development of hybrids derivatives of oxadiazole-based benzothiazole (1–17) and diversity in derivatives was achieved using variety of aryl ring of S-substituted benzothiazole to see the effect on the biological activities. All the synthesized derivatives were evaluated for their in vitro α-glucosidase and urease inhibitory potential. The α-glucosidase and urease inhibition profile of the new derivatives represents moderate to good inhibitory potential with IC₅₀ values ranging from 4.60 ± 1.20 µM to 48.40 ± 7.70 µM (α-glucosidase) and 8.90 ± 2.80 to 57.30 ± 7.70 µM (urease) respectively. The results were compared to standard acarbose (38.60 ± 4.50 µM) and thiourea (58.70 ± 6.80 µM) drugs respectively. Among the synthesized series, the analogs 1 having IC₅₀ values of and 4.60 ± 1.20 (α-glucosidase), 8.90 ± 2.80 (urease) and 2 with IC₅₀ values of 5.60 ± 1.60 (α-glucosidase) and 10.90 ± 2.10(urease) were found to be significantly active against targeted α-glucosidase and urease enzymes. The structure of all the newly synthetics scaffolds were confirmed by using different types of spectroscopic techniques such as HREI-MS, ¹H- and ¹³C- NMR spectroscopy. The molecular docking studies of the synthesized derivatives showed good correlations with the experimental findings. The binding modes of active compounds and their interactions with active site residues revealed them as possible anti-diabetics and anti-urease leads. The degree of activity and docking studies displayed by the novel innovative structural hybrids of oxadiazole-based benzothiazole moieties make these compounds new active leads and promising candidates for the development of anti-diabetics and anti-urease agents.     

N-Benzylgalactonoamidines as potent β-galactosidase inhibitors

A series of N-benzylgalactonoamidines was synthesized to probe their inhibitory ability during the hydrolysis of o-nitrophenyl-β-d-galactopyranoside by β-galactosidase (Aspergillus oryzae). All compounds are characterized as potent competitive inhibitors with inhibition constants (K_i) in the low nanomolar range (12–48 nM). The structure of the inhibitors mimics the bond-lengthening during the hydrolysis and the aromatic aglycon of the substrate. The electronic nature of the substituent in p-position of the aglycon influences the overall inhibitory ability most when compared to the unsubstituted parent compound.     

Novel sulfonamide-functionalized arylidene indolones as potent α-glucosidase inhibitors: Synthesis,characterization, and in vitro and in silico studies

3-Arylidene-1-(2,6-dichlorophenyl)indolones and in particular their 5-methylaminosulfonyl derivatives efficiently inhibit α-glucosidase enzyme. The results are corroborated by in silico docking studies which show the binding of aminosulfonyl derivatives to be more favorable due to additional hydrogen bonding. The most active compound of the series shows the IC₅₀ of 6.19 μm.     

Synthesis of potent inhibitors of β-ketoacyl-acyl carrier protein synthase III as potential antimicrobial agents

Mycobacterium tuberculosis FabH, an essential enzyme in the mycolic acid biosynthetic pathway, is an attractive target for novel anti-tubercolosis agents. Structure-based design and synthesis of 1-(4-carboxybutyl)-4-(4-(substituted benzyloxy)phenyl)-1H-pyrrole-2-carboxylic acid derivatives 7a-h, a subset of eight potential FabH inhibitors, is described in this paper. The Vilsmeier-Haack reaction was employed as a key step. The structures of all the newly synthesized compounds were identified by IR, 1H-NMR, 13C-NMR, ESI-MS and HRMS. The alamarBlue? microassay was employed to evaluate the compounds 7a-h against Mycobacterium tuberculosis H??Rv. The results demonstrate that the compound 7d possesses good in vitro antimycobacterial activity against Mycobacterium tuberculosis H??Rv (Minimum Inhibitory Concentration value [MIC], 12.5 μg/mL).These compounds may prove useful in the discovery and development of new anti-tuberculosis drugs.     

Synthesis of new 1,4- and 1,5-disubstituted N-ethyl acetate and N-α-butyro-γ-lactone alkylimidazole derivatives as N-acylhomoserine lactone analogs

New alkylimidazoles functionalized with a homoserine lactone or an alkyloxycarbonyl moiety have been synthesized as N-acylhomoserine lactones (AHLs) analogs. The 1,4-disubstituted imidazole derivatives were prepared by alkylation of 4(5)-alkylimidazoles with α-bromo-γ-butyrolactone or ethyl α-bromoacetate. An alternative route was preferred for the synthesis of their 1,5-disubstituted counterparts based on the use of a N₁-protected alkylimidazole, its alkylation to an N₃-imidazolyl-α-acetate and deprotection to the desired 1,5-disubstituted esters and subsequent alkylation of the acetate moiety with cyclic ethylene sulfate followed by acid-catalyzed cyclization. The ability to modulate bacterial quorum sensing of all new compounds was compared to that of previously reported AHL analogs in which the amide bond is replaced by a heterocyclic group.     

Synthesis characterization and evaluation of novel triazole based analogs as a acetylcholinesterase and α-glucosidase inhibitors

A series of novel triazole analogs (10a-k) bearing piperidine were synthesized in an aprotic solvent on the most effective pharmacophore with acetylcholinesterase (AChE) and α-glucosidase inhibitory activity. Triazole analogs (10a-k) were obtained in excellent yields (75–90 %) and characterized by EI-MS, IR, ¹³C NMR and ¹H NMR. The newly synthesized triazole analogs (10a-k) showed potent AChE inhibitory activity in the range of K_i = 0.0155 ± 1.25 µM to 0.557 ± 0.50 µM, IC₅₀ = 0.031 ± 0.85 to 0.537 ± 0.76 µM than Eserine (0.04 ± 0.001 µM) having strong electron-withdrawing fluorine group on the pyridine ring was recorded as a most potent inhibitor of AChE while (%) inhibition against α-glucosidase was ranging between 52.36 ± 1.67 to 85.35 ± 1.39. The kinetic study predicted that triazole analogs (10a-k) followed the un-competitive and mixed type of inhibition against AChE. In silico molecular docking was performed at the active site of the AChE co-crystal structure (PDB ID:1NEN). The results of molecular docking corelate will with the experimental findings.     

Synthesis and biological investigation of the β-thiolactone and β-lactam analogs of tetrahydrolipstatin

The synthesis of β-thiolactone and β-lactam analogs of tetrahydrolipstatin is described from a common late-stage β-lactone derivative. These analogs, and a cis-disubstituted β-lactone analog of tetrahydrolipstatin, were screened for activity against porcine pancreatic lipase and for inhibition of cell growth of a panel of four human cancer lines.     

Synthesis and biological evaluation of new dipicolylamine zinc chelators as metallo-β-lactamase inhibitors

Antibiotics are key drugs in modern healthcare, especially in hospitals, where multiresistant bacteria resides and is a potential threat to human health. In the present work, a new series of adjuvants working synergistically with the carbapenem meropenem, in which a selective zinc-chelating agent was covalently linked to the small bacterial peptide D-Ala-D-Ala, was synthesized and tested against VIM-2 and NDM-1 metallo-β-lactamases (MBLs). The nature of the linker was modified in a structure-activity relationship study. Compound 1i, having an ethyl piperidine linker, lowered the MIC of meropenem from 32 to 64?mg/L to 2 and 1–2?mg/L against VIM-2- and NDM-1-producing clinical isolates, respectively. The IC₅₀ value of 1i against VIM-2 was 9.8 and 2.2?μM after 5 and 20?min, respectively. Compound 1i also showed intrinsic toxicity against three eukaryotic human tumoral cell lines between 50 and 120?μM.     

Identification of indoline-2-thione analogs as novel potent inhibitors of α-melanocyte stimulating hormone induced melanogenesis

Based on the hits, 3,4-dihydroquinazoline-2-thione (1) and benzimidazole-2-thione (2), a series of indole-2-thione (3) and indole-2-thiol inhibitors (4) of melanogenesis were designed, synthesized and evaluated in melanoma B16 cells under the stimulant of α-melanocyte stimulating hormone (α-MSH). The indole-2-thione compounds (3a-g) exhibited an effective inhibitory activity on melanin synthesis. The Structure-Activity Relationship (SAR) studies of 2 have revealed that in potent inhibitor 3a (>100% inhibition at 30 μM, IC50=1.40 μM) the role of nitrogen (3-N) at 3-position is insignificance. In addition, the hydrophobic substituents of 3 were better than the hydrophilic one. However, conversion of thione (-C=S, 3) to thiol (-C-SH, 4) led to decrease in the potency.     

Synthesis,in silico and in vitro Evaluation of Novel Oxazolopyrimidines as Promising Anticancer Agents

New potential bioactive oxazolopyrimidines have been synthesized using two main approaches: the pyrimidine ring annulation on a functionalized oxazole and the benzoyl bromide trimerization followed by rearrangement and formation of the oxazolo[5,4-d]pyrimidine scaffold. The docking analyzes have shown that 7-piperazine substituted oxazolo[4,5-d]pyrimidines 8a – 8c could be potential VEGFR2 inhibitors with high free energy of ligand–protein complex formation (ΔG: −10.1, −9.6, −9.8 kcal/mol, respectively). In vitro antitumor assays confirmed theoretical predictions that oxazolo[4,5-d]pyrimidines 8a – 8c containing positively charged piperazine moiety should demonstrate significantly higher cytotoxic effects. 4-[5-(4-Chlorophenyl)-2-phenyl[1,3]oxazolo[4,5-d]pyrimidin-7-yl]piperazin-1-ium trifluoroacetate ( 8c ) exhibited a slightly higher antiproliferative effect (IC₅₀=0.21 μm ) than doxorubicin (IC₅₀=0.36 μm ) on MDA-MB-231 cell line and has relatively good results on OVCAR-3 (IC₅₀=1.7 μm ) and HCT-116 (IC₅₀=0.24 μm ) cells.     

Synthesis of new β- and γ-benzyloxy-S-glutamic acid derivatives and evaluation of their activity as inhibitors of excitatory amino acid transporters

An efficient stereoselective preparation of the two enantiomerically pure diasteroisomers of γ-benzyloxy-S-glutamic acid was performed using trans-4-hydroxy-l-proline as a source of chirality, while the erythro and threo isomers of β-benzyloxy-S-glutamic acid were prepared starting from (R)-Garner's aldehyde. All new derivatives were tested for their inhibitory activity against excitatory amino acid transporters in a rat synaptosomal preparation and their IC₅₀ values were compared to that of TBOA, a one carbon lower homologue commonly used as the reference blocker of glutamate transporters.     

Synthesis of a new class of bis(thiourea)hydrazide pseudopeptides as potential inhibitors of β-sheet aggregation

The modular synthesis of a novel pseudopeptide scaffold based on a bis(thiourea)hydrazide motif is reported. This compound class is designed to display "amphifinity", i.e. association with a peptide strand on one but not the other face of the scaffold, and hence could potentially inhibit β-sheet aggregation.     

Synthesis and evaluation of new phosphonated δ-lactam and glutarimide derivatives as angiotensin converting enzyme inhibitors

An efficient synthesis of new γ,δ-insaturated δ-lactam and glutarimide derivatives bearing a phosphonomethyl group from a common allylphosphonate precursor is described. Our approach is based on a two-step procedure involving the preparation of phosphonated-1,5-ketoester and −1,5-diester followed by an amidation–heterocyclization sequence. The first step proceeds via Michael's addition of ethyl acetoacetate and diethyl malonate on an allylphosphonate starting material. The second step consists of a base-promoted intramolecular amidation-cyclization sequence with primary amines, which accounts for the construction of δ-lactams and glutarimide skeletons. We performed the evaluation of angiotensin I-converting enzyme (ACE) inhibition using an in vitro enzyme assay on six new compounds. Five compounds showed potent ACE inhibitory activity, with IC₅₀ values ranging from 0.02 to 0.27 mg/ml. Compared with Captopril, used as a reference drug, two new glutarimide derivatives exhibited higher efficiency ACE inhibition activity.     

Synthesis and study of N,N′-disubstituted derivatives of pyromellitic diimide

Russian Chemical Bulletin - New N, N′-bis(4,6-dimethylpyrimidin-2-yl)- and N, N′-bis(2,3,5,6-tetrafluorophenyl)-substituted pyromellitic diimides were synthesized. Their properties were...     

Synthesis and acid-base properties of new β-diaminophosphoryl compounds

Russian Journal of Organic Chemistry -     

Synthesis of uronic-noeurostegine--a potent bacterial β-glucuronidase inhibitor

Inhibition of β-glucuronidases has recently been shown to be useful in alleviating drug toxicity for common colon cancer chemotherapeutic CPT-11 (also called Irinotecan). We have prepared a new compound of the nortropane-type, uronic-Noeurostegine, and demonstrated that this is a competitive and potent E. coli β-glucuronidase inhibitor, while inhibition of the mammalian β-glucuronidase from bovine liver was found to be less significant. Although not intended, two other compounds having N-ethyl and N-(4-hydroxybutyl) substituents were also prepared in this study due to the sluggish debenzylation in the final step. The N-substituents are believed to come from reaction with the solvents used being ethanol and THF, respectively. These compounds also inhibited the two β-glucuronidases albeit to a lesser extent compared to the parent compound. Noeurostegine and the three uronic-noeurostegines were additionally evaluated as inhibitors against a wide panel of glycosidases with the former showing potent inhibition of rat intestinal lactase and trehalase, whereas the latter was found to be inactive.     

Dicyanoanilines as potential and dual inhibitors of α-amylase and α-glucosidase enzymes: Synthesis,characterization, in vitro,in silico,and kinetics studies

The present study comprised of the synthesis of dicyanoaniline derivatives of pyridine, thiophene, furan, and substituted phenyl 1–29. All synthetic derivatives were evaluated for their potential to inhibit α-amylase and α-glucosidase enzymes. The synthesized compounds are classified into three categories A, B, and C based on variable substituents at R₁ and R_2, and the structure–activity relationship was discussed accordingly. Amongst twenty-nine derivatives, 1–29, five compounds 2, 9, 18, 23, and 24 displayed excellent inhibition against α-amylase and α-glucosidase enzymes with the IC₅₀ values ranging between 20.33 ± 0.02–25.50 ± 0.06 µM and 21.01 ± 0.12–27.75 ± 0.17 µM, respectively, while other compounds showed moderate to weak inhibition against both enzymes. Acarbose was used as the positive control in this study. The enzyme kinetic studies showed non-competitive and un-competitive types of inhibition mechanism against α-amylase and α-glucosidase enzymes, respectively. In silico studies have demonstrated the involvement of these molecules in numerous binding interactions within the active site of the enzyme.     

Design,synthesis, in vitro and in silico studies of naproxen derivatives as dual lipoxygenase and α-glucosidase inhibitors

A series of 28 novel naproxen derivatives (4a-f, 5a-f, 6a-d, 7a-f, and 8a-f) have been designed, synthesized, and characterized. The synthesized derivatives were assessed as dual inhibitors for 15-lipoxygenase (LOX) and α-glucosidase enzymes and checked for cytotoxicity and ADME studies. The inhibitory potential of naproxen derivatives for 15- LOX was checked through two different methods, the UV absorbance method and the Chemiluminescence method. The biological activities result revealed that through the UV absorbance method, compound 4f (IC₅₀ 21.31 ± 0.32 µM) was found potent among the series followed by compounds 4e (IC₅₀ 36.53 ± 0.51 µM) and 4d (IC₅₀ 49.62 ± 0.12 µM) against standard drug baicalein (IC₅₀ 22.46 ± 1.32 µM) and quercetin (IC₅₀ 2.34 ± 0.35 µM), while through chemiluminescence method tested compounds showed significant 15-LOX inhibition at the range of IC₅₀ 1.13 ± 0.62 µM ?123.47 ± 0.37 µM. Among these compounds, 4e (IC₅₀ 1.13 ± 0.62 µM), 5b (IC₅₀ 1.19 ± 0.43 µM), 8c (IC₅₀ 1.23 ± 0.35 µM) were found most potent inhibitors against quercetin (IC₅₀ 4.86 ± 0.14 µM), and baicalein (IC₅₀ 2.24 ± 0.13 µM). The chemiluminescence method was found more sensitive than the UV method to identify 15-LOX inhibitors. Interestingly all synthesized compounds showed significant α-glucosidase inhibitory activity (IC₅₀ 1.0 ± 1.13 µM ? 367.2 ± 1.23 µM) even better than the standard drug acarbose (IC₅₀ 375.82 ± 1.76 µM), while compound 6c (IC₅₀ 1.0 ± 1.13 µM) and 7c (IC₅₀ 1.1 ± 1.17 µM) were found most potent compounds among the series even many folds better than the standard drug. The cell viability results showed that all compounds were less toxic, maintained cellular viability at the range of 99.8 ± 1.3% to 63.7 ± 1.5%. ADME and molecular docking studies supported drug-likeness and binding interactions of compounds with the targeted enzymes.