Carbonic anhydrase and acetylcholinesterase inhibitory effects of carbamates and sulfamoylcarbamates

Design, synthesis, and biological evaluation of 3-benzenesulfonamide-linked 3-hydrazinoisatin derivatives as carbonic anhydrase inhibitors

A new series of isatin-linked benzenesulfonamide derivatives (9a-w) were synthesized using the tail approach and assayed for their inhibitory potency against four different human carbonic anhydrase (hCA) isoforms, hCA I, II, IX, and XII. Most of these synthesized compounds exhibited interesting inhibition potency against isoforms hCA I, IX, and XII in the nanomolar range and by taking the standard drug acetazolamide. The most potent compounds in the case of hCA I were 9c (435.8 nM) and 9s (956.4 nM), for hCA IX, 9a (60.5 nM), 9d (95.6 nM), 9g (92.1 nM), and 9k (75.4 nM), and for hCA XII, 9p (84.5 nM). However, these compounds showed more selectivity toward hCA IX over hCA I, II, and XII. Thus, these compounds can be further developed as potential lead molecules for the development of isoform-selective hCA IX inhibitors with further structural modifications.

Design, synthesis and in vitro evaluation of novel thiazole-coumarin hybrids as selective and potent human carbonic anhydrase IX and XII inhibitors

The coumarin is one of the most promising classes of non-classical carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. In continuation of our ongoing work on search of coumarin based selective carbonic anhydrase inhibitors, a new series of 6-aminocoumarin based 16 novel analogues of coumarin incorporating thiazole (4a-p) have been synthesized and studied for their hCA inhibitory activity against a panel of human carbonic anhydrases (hCAs). Most of these newly synthesized compounds exhibited interesting inhibition constants in the nanomolar range. Among the tested compounds, the compounds 4f having 4-methoxy substitution exhibited activity at 90.9 nM against hCA XII isoform. It is noteworthy to see that all compounds were specifically and selectively active against isoforms hCA IX and hCA XII, with Ki under 1000 nM range. It is anticipated that these newly synthesized coumarin-thiazole hybrids (4a-p) may emerge as potential leads candidates against hCA IX and hCA XII as selective inhibitors compared to hCA I and hCA II.

Design, synthesis and anticholinergic properties of novel α-benzyl dopamine, tyramine, and phenethylamine derivatives

Due to the important biological properties of dopamine, phenethylamine, and tyramine derivatives in the central nervous system, herein the synthesis of novel α-benzyl dopamine, phenethylamine, and tyramine derivatives is described. The title compounds were synthesized starting from 3-phenylpropanoic acids and methoxybenzenes in six or seven steps. Firstly, 3-(2,3-dimethoxyphenyl)propanoic acid (11) and 3-(3,4-dimethoxyphenyl)propanoic acid (12) were selectively brominated with N-bromosuccinimide (NBS). The Friedel-Crafts acylation of methoxylated benzenes with these brominated acids or commercially available 3-phenylpropanoic acid in polyphosphoric acid gave the desired dihydrochalcones. α-Carboxylation of dihydrochalcones, reduction of benzylic carbonyl groups, hydrolysis of esters to acid derivatives, and the Curtius rearrangement reaction of acids followed by in situ synthesis of carbamates from alkyl isocyanates and hydrogenolysis of the carbamates afforded the title compounds in good total yields. Alzheimer's disease (AD) and Parkinson's disease (PD) are chronic neurodegenerative diseases that become serious over time. However, the exact pathophysiology of both diseases has not been revealed yet. There have been many different approaches to the treatment of patients for many years, especially studies on the cholinergic system cover a wide area. Within the scope of this study, the inhibition effects of dopamine-derived carbamates and amine salts on the cholinergic enzymes AChE and BChE were examined. Dopamine-derived carbamate 24a-i showed inhibition in the micro-nanomolar range; compound 24d showed a Ki value of 26.79 nM against AChE and 3.33 nM against BChE, while another molecule, 24i, showed a Ki range of 27.24 nM and 0.92 nM against AChE and BChE, respectively. AChE and BChE were effectively inhibited by dopamine-derived amine salts 25j-s, with Ki values in the range of 17.70 to 468.57 µM and 0.76-211.23 µM, respectively. Additionally, 24c, 24e and 25m were determined to be 60, 276 and 90 times more selective against BChE than AChE, respectively.

Selenocarbamates as a novel prodrug-based approach towards Carbonic Anhydrase inhibition

A study on the activity of selenocarbamates as a novel chemotype acting as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors is reported. Undergoing CA‐mediated hydrolysis, selenocarbamates release selenolates behaving as zinc binding groups and effectively inhibiting CAs. A series of selenocarbamates characterised by high molecular diversity and complexity have been studied against different human CA isoforms such as hCA I, II, IX and XII. Selenocarbamates behave as masked selenols with potential biological applications as prodrugs for CAs inhibition‐based strategies. X‐ray studies provided insights into the binding mode of this novel class of CA inhibitors.

Determination of radioprotective and genotoxic properties of sulfamide derivatives

Some potential drug active substances with the ability to reduce the effects of radiation on human tissues and cells were investigated. For this purpose, eight different types of sulfamide derivatives were synthesized and nuclear radiation protection parameters were determined. Neutron radiation reduction parameters such as the half-value layer effective removal cross-sections, mean free path, and the number of particles passing through the sample were determined with GEANT4 code. Additionally, the gamma radiation attenuation parameters of the materials examined were determined using Phy-X/PSD software in the energy area of 0.015–15 MeV. These parameters are the half-value layer, mass attenuation coefficient, mean free path, exposure buildup factor and effective atomic number. Neutron radiation absorption experiments were applied using an 241Am-Be fast neutron source. All results obtained for neutron radiation were compared with paraffin and water. It has been found that the ability of sulfamide derivatives to absorb these radiations is superior to reference materials. To determine whether these derivatives could have adverse effects on human health, their genotoxic potential was determined using the Ames/Salmonella bacterial reversion test. The results showed that these derivatives can be considered genotoxically safe in tests at concentrations up to 5 mM. Thus, it is suggested that the derivative materials examined in this study can be used as active substances for a drug to be made for protection against both neutron and gamma radiation.

Design and development of novel series of indole-3-sulfonamide ureido derivatives as selective carbonic anhydrase II inhibitors

Indole is a privileged moiety with a wide range of bioactivities, making it a popular scaffold in drug design and development studies as well as in synthetic chemistry. Here, novel urea derivatives of indole, containing sulfonamide at position-3 of indole, were synthesized using a well-known tail approach, as carbonic anhydrases (CAs; EC 4.2.1.1) inhibitors. All the newly synthesized molecules were screened for their CA-inhibitory activity against four clinically relevant isoforms of human-origin carbonic anhydrase (hCA), that is, hCA I, hCA II, hCA IX, and hCA XII. These compounds were specifically active against hCA II, more than against hCA I, hCA IX, and hCA XII. Derivative 6l was found to be most active, with a K_i value of 7.7 µM against hCA II.

Benzenesulfonamide derivatives as potent acetylcholinesterase, α-glycosidase, and glutathione S-transferase inhibitors: biological evaluation and molecular docking studies

Sulfonamide derivatives exhibit a wide biological activity and can function as potential medical molecules in the development of a drug. Studies have reported that the compounds have an effect on many enzymes. In this study, the derivatives of amine sulfonamide (1i-11i) were prepared with reduced imine compounds (1-11) with NaBH4 in methanol. The synthesized compounds were fully characterized by spectral data and analytical. The effect of the synthesized derivatives on acetylcholinesterase (AChE), glutathione S-transferase (GST) and α-glycosidase (α-GLY) enzymes were determined. For the AChE and α-GLY, the most powerful inhibition was observed on 10 and 10i series with KI value in the range 2.26 ± 0.45-3.57 ± 0.97 and 95.73 ± 13.67-102.45 ± 11.72 µM, respectively. KI values of the series for GST were found in the range of 22.76 ± 1.23-49.29 ± 4.49. Finally, the compounds have a stronger inhibitor in lower concentrations by the attachment of functional electronegative groups such as two halogens (-Br and -CI), -OH to the benzene ring and -SO2NH2. The crystal structures of AChE, α-GLY, and GST in complex with selected derivatives 4 and 10 show the importance of the functional moieties in the binding modes within the receptors.Communicated by Ramaswamy H. Sarma.

Synthesis, molecular docking and molecular dynamics studies of novel tacrine-carbamate derivatives as potent cholinesterase inhibitors

In the present study, new tacrine derivatives containing carbamate group were synthesized and their acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibition activities were evaluated. All synthesized compounds inhibited both cholinesterases at nanomolar level. Among them, ((1,2,3,4-tetrahydroacridin-9-yl)amino)ethyl(3-nitrophenyl) carbamate (6k) showed the best inhibitor activity against AChE and BuChE with IC₅₀ value of 22.15 nM and 16.96 nM, respectively. The calculated selectivity index revealed that the synthesized compounds (exclude 6l) have stronger inhibitory activity against BuChE than AChE. The most selective compound was 2-((1,2,3,4-tetrahydroacridin-9-yl)amino)ethyl(4-methoxyphenyl)-carbamate (6b) with the selectivity index of 0.12. Molecular modeling approaches were employed to understand the interaction between the synthesized compounds and proteins. As carbamate derivatives can act as pseudo-irreversible inhibitors of AChE and BuChE, covalent docking approaches was applied to determine the binding modes of novel compounds at binding sites of cholinesterase enzymes.

ADME properties, bioactivity and molecular docking studies of 4-amino-chalcone derivatives: new analogues for the treatment of Alzheimer, glaucoma and epileptic diseases

In this study, in vitro inhibition effects of (E)-1-(4-aminophenyl)-3-(aryl) prop-2-en-1-one (4-amino-chalcones) derivatives (3a-o) on acetylcholinesterase (AChE) enzyme and human erythrocyte carbonic anhydrase I and II isoenzymes (hCA I- II) were investigated. And also, the biological activities of 4-amino-chalcone derivatives against enzymes which names are acetylcholinesterase (PDB ID: 1OCE), human Carbonic Anhydrase I (PDB ID: 2CAB), human carbonic anhydrase II (PDB ID: 3DC3), were compared. After the results obtained, ADME/T analysis was performed in order to use 4-amino-chalcone derivatives as a drug in the future. Effective inhibitors of carbonic anhydrase I and II isozymes (hCAI and II) and acetylcholinesterase (AChE) enzymes with Ki values in the range of 2.55 ± 0.35-11.75 ± 3.57 nM for hCA I, 4.31 ± 0.78-17.55 ± 5.86 nM for hCA II and 96.01 ± 25.34-1411.41 ± 32.88 nM for AChE, respectively, were the 4-amino-chalcone derivatives (3a-o) molecules.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-021-00094-x.

Synthesis of novel tris-chalcones and determination of their inhibition profiles against some metabolic enzymes

In this study, we report the synthesis of novel tris-chalcones and testing of human carbonic anhydrase I, and II isoenzymes (hCA I, and hCA II), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α-glycosidase (α-Gly) inhibitors for the development of novel chalcone structures towards for treatment of some diseases. The compounds demonstrated K_i values between 13.6 ± 1.1 and 50.0 ± 17.1 nM on hCA I, 9.9 ± 0.8 and 39.5 ± 15.1 nM on hCA II, 3.1 ± 0.2 and 20.1 ± 1.9 nM on AChE, 4.9 ± 0.4 and 14.7 ± 5.2 nM on BChE and 3.9 ± 0.2 and 22.4 ± 10.7 nM on α-Gly enzymes. The results revealed that novel tris-chalcones can have promising drug potential for glaucoma, leukaemia, epilepsy; Alzheimer's disease that was associated with the high enzymatic activity of hCA I, hCA II, AChE, and BChE enzymes.

Discovery of a novel series of indolylchalcone-benzenesulfonamide hybrids acting as selective carbonic anhydrase II inhibitors

The primary sulfonamide group is one of the most efficient zinc binding group (ZBG) for designing carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. In the present study primary sulfonamide linked with indolylchalcone were designed. The newly synthesized molecules (5a-r) were examined against four human (h) CA isoforms (hCA I, hCA II, hCA IX and hCA XIII). These sulfonamides showed good inhibition activity against isoforms hCA I, hCA II and hCA XIII. Compound 5i (2.3 nM), 5m (2.4 nM), 5o (3.6 nM) and 5q (7.0 nM) were more potent than standard drug AAZ (12.1 nM) against isoform hCA II, respectively. Most of the other compounds in the present series inhibited hCA XIII and hCA IX in the range of 50 nM - 100 nM.

Synthesis of calix[4]azacrown substituted sulphonamides with antioxidant, acetylcholinesterase, butyrylcholinesterase, tyrosinase and carbonic anhydrase inhibitory action

A series of novel calix[4]azacrown substituted sulphonamide Schiff bases was synthesised by the reaction of calix[4]azacrown aldehydes with different substituted primary and secondary sulphonamides. The obtained novel compounds were investigated as inhibitors of six human (h) isoforms of carbonic anhydrases (CA, EC 4.2.1.1). Their antioxidant profile was assayed by various bioanalytical methods. The calix[4]azacrown substituted sulphonamide Schiff bases were also investigated as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase enzymes, associated with several diseases such as Alzheimer, Parkinson, and pigmentation disorders. The new sulphonamides showed low to moderate inhibition against hCAs, AChE, BChE, and tyrosinase enzymes. However, some of them possessed relevant antioxidant activity, comparable with standard antioxidants used in the study.

Potent Acetylcholinesterase Inhibitors: Potential Drugs for Alzheimer's Disease

Alzheimer's disease (AD) is one of the cognitive or memory-related impairments occurring with advancing age. Since its exact mechanism is not known, the full therapy has still not been found. Acetylcholinesterase (AChE) has been reported to be a viable therapeutic target for the treatment of AD and other dementias. To this end, acetylcholinesterase inhibitors (AChEIs) are commonly used. AChE is a member of the hydrolase enzyme family. A hydrolase is an enzyme that catalyzes the hydrolysis of a chemical bond. AChE is useful for the development of novel and mechanism-based inhibitors. It has a role in the breakdown of acetylcholine (ACh) neurotransmitters, such as acetylcholinemediated neurotransmission. AChEIs are the most effective approaches to treat AD. AChE hydrolyzes ACh to acetate and choline, as an important neurotransmitter substance. Recently, Gülçin and his group explored new AChEIs. The most suggested mechanism for AD is the deficiency of ACh, which is an important neurotransmitter. In this regard, AChEIs are commonly used for the symptomatic treatment of AD. They act in different ways, such as by inhibiting AChE, protecting cells from free radical toxicity and β-amyloid-induced injury or inhibiting the release of cytokines from microglia and monocytes. This review focuses on the role of AChEIs in AD using commonly available drugs. Also, the aim of this review is to research and discuss the role of AChEIs in AD using commonly available drugs. Therefore, in our review, related topics like AD and AChEIs are highlighted. Also, the latest work related to AChEIs is compiled. In recent research studies, novel natural and synthetic AChEIs, used for AD, are quite noteworthy. These studies can be very promising in detecting potent drugs against AD.

Molecular docking and inhibition profiles of some antibiotics on lactoperoxidase enzyme purified from bovine milk

Antibiotics are generally used for human and veterinary applications to preserve and to control microbial diseases. Milk has a biologically significant enzyme known as lactoperoxidase (LPO) that is a member of peroxidase family. In metabolism, LPO has ability to catalyze the transformation of thiocyanate (SCN^-) to hypothiocyanite (OSCN^-) that is an antibacterial agent and the reaction occurs with hydrogen peroxide. In this work, LPO inhibition effects of some antibiotics including cefazolin, oxytetracycline, flunixin meglumine, cefuroxime, tylosin, vancomycin, chloramphenicol and lincomycin were tested. Among the antibiotics cefazolin was indicated the strongest inhibitory efficacy. The half maximal inhibitory concentration (IC₅₀) and the inhibition constant (K_i) values of cefazolin were found as 8.19 and 34.66 µM, respectively. It was shown competitive inhibition. 5-Methyl-1,3,4-thiadiazol-2-yl moiety activity plays a key role in the inhibition mechanism of cefazolin.Communicated by Ramaswamy H. Sarma.

Synthesis of nitrogen, phosphorus, selenium and sulfur-containing heterocyclic compounds - Determination of their carbonic anhydrase, acetylcholinesterase, butyrylcholinesterase and α-glycosidase inhibition properties

Sulfur-containing pyrroles (1-3), tris(2-pyridyl)phosphine(selenide) sulfide (4-5) and 4-benzyl-6-(thiophen-2-yl)pyrimidin-2-amine (6) were synthesized and characterized by elemental analysis, IR and NMR spectra. In this study, the synthesized compounds of nitrogen, phosphorus, selenium and sulfur-containing heterocyclic compounds (1-6) were evaluated against the human erythrocyte carbonic anhydrase I, and II isoenzymes, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and α-glycosidase enzymes. The synthesized heterocyclic compounds showed IC₅₀ values in range of 33.32-60.79 nM against hCA I, and 37.05-66.64 nM against hCA II closely associated with various physiological and pathological processes. On the other hand, IC₅₀ values were found in range of 13.13-22.21 nM against AChE, 0.54-31.22 nM against BChE, and 13.51-26.55 nM against α-glycosidase as a hydrolytic enzyme. As a result, nitrogen, phosphorus, selenium and sulfur-containing heterocyclic compounds (1-6) demonstrated potent inhibition profiles against indicated metabolic enzymes. Therefore, we believe that these results may contribute to the development of new drugs particularly in the treatment of some global disorders including glaucoma, Alzheimer's disease and diabetes.

Sulphonamides incorporating 1,3,5-triazine structural motifs show antioxidant, acetylcholinesterase, butyrylcholinesterase, and tyrosinase inhibitory profile

A series of 16 novel benzenesulfonamides incorporating 1,3,5-triazine moieties substituted with aromatic amines, dimethylamine, morpholine and piperidine were investigated. These compounds were assayed for antioxidant properties by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, 2,2`-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical decolarisation assay and metal chelating methods. They were also investigated as inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase, which are associated with several diseases such as Alzheimer, Parkinson and pigmentation disorders. These benzenesulfonamides showed moderate DPPH radical scavenging and metal chelating activity, and low ABTS cation radical scavenging activity. Compounds 2 b, 3d and 3 h showed inhibitory potency against AChE with % inhibition values of >90. BChE was also effectively inhibited by most of the synthesised compounds with >90% inhibition potency. Tyrosinase was less inhibited by these compounds.

Design, synthesis, in vitro and in vivo evaluation of benzylpiperidine-linked 1,3-dimethylbenzimidazolinones as cholinesterase inhibitors against Alzheimer's disease

Cholinesterase inhibitor plays an important role in the treatment of patients with Alzheimer's disease (AD). Herein, we report the medicinal chemistry efforts leading to a new series of 1,3-dimethylbenzimidazolinone derivatives. Among the synthesised compounds, 15b and 15j showed submicromolar IC₅₀ values (15b, eeAChE IC₅₀ = 0.39 ± 0.11 µM; 15j, eqBChE IC₅₀ = 0.16 ± 0.04 µM) towards acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Kinetic and molecular modelling studies revealed that 15b and 15j act in a competitive manner. 15b and 15j showed neuroprotective effect against H₂O₂-induced oxidative damage on PC12 cells. This effect was further supported by their antioxidant activity determined in a DPPH assay in vitro. Morris water maze test confirmed the memory amelioration effect of the two compounds in a scopolamine-induced mouse model. Moreover, the hepatotoxicity of 15b and 15j was lower than tacrine. In summary, these data suggest 15b and 15j are promising multifunctional agents against AD.

Synthesis of a new series of 3-functionalised-1-phenyl-1,2,3-triazole sulfamoylbenzamides as carbonic anhydrase I, II, IV and IX inhibitors

The synthesis of a novel series of 3-functionalised benzenesulfonamides incorporating phenyl-1,2,3-triazole with an amide linker was achieved by using the "click-tail" approach. The new compounds, including the intermediates, were assayed as inhibitors of human carbonic anhydrase (CA, EC 4.2.1.1) isoforms hCA I and II (cytosolic isoforms) and also for hCA IV and IX (transmembrane isoforms) taking acetazolamide as standard drug. Most of these compounds exhibited excellent activity against all these isoforms. hCA I was inhibited with Kis in the range of 50.8-966.8 nM, while the glaucoma associated hCA II was inhibited with Kis in the range of 6.5-760.0 nM. Isoform hCA IV was inhibited with Kis in the range of 65.3-957.5 nM, whereas the tumor associated hypoxia induced hCA IX was inhibited with Kis in the range of 30.8-815.9 nM. The structure activity relationship study for the 3-functionalised-1-phenyl-1,2,3-triazole sulfamoylbenzamides against these isoforms was also inferred from the results.

Novel 2-aminopyridine liganded Pd(II) N-heterocyclic carbene complexes: Synthesis, characterization, crystal structure and bioactivity properties

In this work, the synthesis, crystal structure, characterization, and enzyme inhibition effects of the novel a series of 2-aminopyridine liganded Pd(II) N-heterocyclic carbene (NHC) complexes were examined. These complexes of the Pd-based were synthesized from PEPPSI complexes and 2-aminopyridine. The novel complexes were characterized by using ¹³C NMR, ¹H NMR, elemental analysis, and FTIR spectroscopy techniques. Also, crystal structures of the two compounds were recorded by using single-crystal X-ray diffraction assay. Also, these complexes were tested toward some metabolic enzymes like α-glycosidase, aldose reductase, butyrylcholinesterase, acetylcholinesterase enzymes, and carbonic anhydrase I, and II isoforms. The novel 2-aminopyridine liganded (NHC)PdI₂(2-aminopyridine) complexes (1a-i) showed Ki values of in range of 5.78 ± 0.33-22.51 ± 8.59 nM against hCA I, 13.77 ± 2.21-30.81 ± 4.87 nM against hCA II, 0.44 ± 0.08-1.87 ± 0.11 nM against AChE and 3.25 ± 0.34-12.89 ± 4.77 nM against BChE. Additionally, we studied the inhibition effect of these derivatives on aldose reductase and α-glycosidase enzymes. For these compounds, compound 1d showed maximum inhibition effect against AR with a Ki value of 360.37 ± 55.82 nM. Finally, all compounds were tested for the inhibition of α-glycosidase enzyme, which recorded efficient inhibition profiles with Ki values in the range of 4.44 ± 0.65-12.67 ± 2.50 nM against α-glycosidase.

The green synthesis and molecular docking of novel N-substituted rhodanines as effective inhibitors for carbonic anhydrase and acetylcholinesterase enzymes

Recently, inhibition effects of enzymes such as acetylcholinesterase (AChE) and carbonic anhydrase (CA) has appeared as a promising approach for pharmacological intervention in a variety of disorders such as epilepsy, Alzheimer's disease and obesity. For this purpose, novel N-substituted rhodanine derivatives (RhAs) were synthesized by a green synthetic approach over one-pot reaction. Following synthesis the novel compounds, RhAs derivatives were tested against AChE and cytosolic carbonic anhydrase I, and II (hCAs I, and II) isoforms. As a result of this study, inhibition constant (Ki) were found in the range of 66.35 ± 8.35 to 141.92 ± 12.63 nM for AChE, 43.55 ± 14.20 to 89.44 ± 24.77 nM for hCA I, and 16.97 ± 1.42 to 64.57 ± 13.27 nM for hCA II, respectively. Binding energies were calculated with docking studies as -5.969, -5.981, and -9.121 kcal/mol for hCA I, hCA II, and AChE, respectively.

Synthesis and biological evaluation of bromophenol derivatives with cyclopropyl moiety: Ring opening of cyclopropane with monoester

Trans-(1R*,2R*,3R*)-Ethyl 2-(3,4-dimethoxyphenyl)-3-methylcyclopropane-1-carboxylate (6) and its cis isomer 7 were obtained from the reaction of the methyl isoeugenol (5) with ethyl diazoacetate. The reduction and bromination reactions of the ester 6 and 7 together with the hydrolysis of all esters were carried out. Opening ring of cyclopropane was observed in the reaction of 7 with bromine. The opening of cyclopropane ring with COOR and synthesis of esters, alcohols and acids (6-26) are new. These obtained bromophenol derivatives (6-26) were effective inhibitors of the cytosolic carbonic anhydrase I and II isoforms (hCA I and II) and acetylcholinesterase (AChE) enzymes with Ki values in the range of 7.8 ± 0.9-58.3 ± 10.3 nM for hCA I, 43.1 ± 16.7-150.2 ± 24.1 nM for hCA II, and 159.6 ± 21.9-924.2 ± 104.8 nM for AChE, respectively. Acetylcholinesterase inhibitors are the most popular drugs applied in the treatment of diseases such as Alzheimer's disease, Parkinson's disease, senile dementia, and ataxia, among others.

Synthesis of oxazolidinone from enantiomerically enriched allylic alcohols and determination of their molecular docking and biologic activities

Enantioselective synthesis of functionalized cyclic allylic alcohols via kinetic resolution in transesterifcation with different lipase enzymes has been developed. The influence of the enzymes and temperature activity was studied. By determination of ideal reaction conditions, byproduct formation is minimized; this made it possible to prepare enantiomerically enriched allylic alcohols in high ee's and good yields. Enantiomerically enriched allylic alcohols were used for enantiomerically enriched oxazolidinone synthesis. Using benzoate as a leaving group means that 1 mol % of potassium osmate is necessary and can be obtained high yields 98%. Inhibitory activities of enantiomerically enriched oxazolidinones (8, 10 and 12) were tested against human carbonic anhydrase I and II isoenzymes (hCA I and hCA II), acetylcholinesterase (AChE), and α-glycosidase (α-Gly) enzymes. These enantiomerically enriched oxazolidinones derivatives had K_i values in the range of 11.6 ± 2.1-66.4 ± 22.7 nM for hCA I, 34.1 ± 6.7-45.2 ± 12.9 nM for hCA II, 16.5 ± 2.9 to 35.6 ± 13.9 for AChE, and 22.3 ± 6.0-70.9 ± 9.9 nM for α-glycosidase enzyme. Moreover, they had high binding affinity with -5.767, -6.568, -9.014, and -8.563 kcal/mol for hCA I, hCA II, AChE and α-glycosidase enzyme, respectively. These results strongly supported the promising nature of the enantiomerically enriched oxazolidinones as selective hCA, AChE, and α-glycosidase inhibitors. Overall, due to these derivatives' inhibitory potential on the tested enzymes, they are promising drug candidates for the treatment of diseases like glaucoma, leukemia, epilepsy; Alzheimer's disease; type-2 diabetes mellitus that are associated with high enzymatic activity of CA, AChE, and α-glycosidase.

Characterization of the Propham Biodegradation Pathway in Starkeya sp. Strain YW6 and Cloning of a Novel Amidase Gene mmH

We previously isolated a monocrotophos-degrading strain Starkeya sp. YW6, which could also degrade propham. Here, we show that strain YW6 metabolizes propham via a pathway in which propham is initially hydrolyzed to aniline and then converted to catechol, which is then oxidized via an ortho-cleavage pathway. The novel amidase gene mmH was cloned from strain YW6 and expressed in Escherichia coli BL21(DE3). MmH, which exhibits aryl acylamidase activity, was purified for enzymatic analysis. Bioinformatic analysis confirmed that MmH belongs to the amidase signature (AS) enzyme family and shares 26-50% identity with several AS family members. MmH (molecular mass of 53 kDa) was most active at 40 °C and pH 8.0 and showed high activity toward propham, with K_cat and K_m values of 33.4 s^-1 and 16.9 μM, respectively. These characteristics make MmH suitable for novel amide biosynthesis and environmental remediation.

Chiral AuI - and AuIII -Isothiourea Complexes: Synthesis, Characterization and Application

During an investigation into the potential union of Lewis basic isothiourea organocatalysis and gold catalysis, the formation of gold-isothiourea complexes was observed. These novel gold complexes were formed in high yield and were found to be air- and moisture stable. A series of neutral and cationic chiral gold(I) and gold(III) complexes bearing enantiopure isothiourea ligands was therefore synthesized and fully characterized. The steric and electronic properties of the isothiourea ligands was assessed through calculation of their percent buried volume and the synthesis and analysis of novel iridium(I)-isothiourea carbonyl complexes. The novel gold(I)- and gold(III)-isothiourea complexes have been applied in preliminary catalytic and biological studies, and display promising preliminary levels of catalytic activity and potency towards cancerous cell lines and clinically relevant enzymes.

Synthesis and Biological Evaluation of 4-Sulfamoylphenyl/Sulfocoumarin Carboxamides as Selective Inhibitors of Carbonic Anhydrase Isoforms hCA II, IX, and XII

With the aim to develop potent and selective human carbonic anhydrase inhibitors (hCAIs), we synthesized 4-sulfamoylphenyl/sulfocoumarin benzamides (series 5 a-r and series 7 a-q) and evaluated their inhibition profiles against five isoforms of the zinc-containing human carbonic anhydrase (hCA, EC 4.2.1.1): cytosolic hCA I and II, and the transmembrane isozymes hCA IV, IX, and XII. Compounds 5 a-r were found to selectively inhibit hCA II in the nanomolar range, while being less effective against the other hCA isoforms. As noted from the literature, sulfocoumarin (1,2-benzoxathiine 2,2-dioxide) acts as a "prodrug" inhibitor and is hydrolyzed by the esterase activity of hCA to form 2-hydroxyphenylvinylsulfonic acid, which thereafter binds to the enzyme in a manner similar to that of coumarins and sulfoxocoumarins. All these sulfocoumarins (compounds 7 a-q) were found to be very weak or ineffective as inhibitors of the housekeeping off-target hCA isoforms I and II, and effectively inhibited the transmembrane tumor-associated isoforms IX and XII in the high nanomolar to micromolar ranges. Further structural modifications of these molecules could be useful for the development of effective hCA inhibitors used for the treatment of glaucoma, epilepsy, and cancer.

Iodine-mediated one-pot intramolecular decarboxylation domino reaction for accessing functionalised 2-(1,3,4-oxadiazol-2-yl)anilines with carbonic anhydrase inhibitory action

A practical and transition metal-free one-pot domino synthesis of diversified (1,3,4-oxadiazol-2-yl)anilines has been developed employing isatins and hydrazides as the starting materials, in the presence of molecular iodine. The prominent feature of this domino process involves consecutive condensation, hydrolytic ring cleavage, and an intramolecular decarboxylation, in a one-pot process that leads to the oxidative formation of a C–O bond. Fluorescence properties of some of the representative molecules obtained in this way were studied. The synthesised 2-(1,3,4-oxadiazolo-2-yl)aniline-benzene sulphonamides (8a–o) were screened for their carbonic anhydrase (CA, EC 4.2.1.1) inhibitory activity. Most of the compounds exhibited low micromolar to nanomolar activity against human (h) isoforms hCA I, hCA II, hCA IV, and XII, with some compounds displaying selective CA inhibitory activity towards hCA II with K_Is of 6.4–17.6 nM.

Synthesis, pharmacology and molecular docking on multifunctional tacrine-ferulic acid hybrids as cholinesterase inhibitors against Alzheimer's disease

The cholinergic hypothesis has long been a “polar star” in drug discovery for Alzheimer’s disease (AD), resulting in many small molecules and biological drug candidates. Most of the drugs marketed for AD are cholinergic. Herein, we report our efforts in the discovery of cholinesterases inhibitors (ChEIs) as multi-target-directed ligands. A series of tacrine-ferulic acid hybrids have been designed and synthesised. All these compounds showed potent acetyl-(AChE) and butyryl cholinesterase(BuChE) inhibition. Among them, the optimal compound 10g, was the most potent inhibitor against AChE (electrophorus electricus (eeAChE) half maximal inhibitory concentration (IC₅₀) = 37.02 nM), it was also a strong inhibitor against BuChE (equine serum (eqBuChE) IC₅₀ = 101.40 nM). Besides, it inhibited amyloid β-protein self-aggregation by 65.49% at 25 μM. In subsequent in vivo scopolamine-induced AD models, compound 10g obviously ameliorated the cognition impairment and showed preliminary safety in hepatotoxicity evaluation. These data suggest compound 10g as a promising multifunctional agent in the drug discovery process against AD.