1-(3-Aminomethyl-4-hydroxyphenyl)-3-pyridinyl-2-propen-1-ones: A novel group of tumour-selective cytotoxins

Novel Mannich bases with strong carbonic anhydrases and acetylcholinesterase inhibition effects: 3-(aminomethyl)-6-{3-[4-(trifluoromethyl)phenyl]acryloyl}-2(3H)-benzoxazolones

In this study, a new series of Mannich bases, 3-(aminomethyl)-6-{3-[4-(trifluoromethyl)phenyl]acryloyl}-2( 3H )-benzoxazolones ( 1a-g ), were synthesized by the Mannich reaction. Inhibitory effects of the newly synthesized compounds towards carbonic anhydrases (CAs) and acetylcholinesterase (AChE) enzymes were evaluated to find out new potential drug candidate compounds. According to the inhibitory activity results, Ki values of the compounds 1 and 1a-g were in the range of 12.3 ± 1.2 to 154.0 ± 9.3 nM against hCA I, and they were in the range of 8.6 ± 1.9 to 41.0 ± 5.5 nM against hCA II. Ki values of acetazolamide (AZA) that was used as a reference compound were 84.4 ± 8.4 nM towards hCA I and 59.2 ± 4.8 nM towards hCA II. Ki values of the compounds 1 and 1a-g were in the range of 35.2 ± 2.0 to 158.9 ± 33.5 nM towards AChE. Ki value of Tacrine (TAC), the reference compound, was 68.6 ± 3.8 nM towards AChE. Furthermore, docking studies were done with the most potent compounds 1d , 1g , and 1f (in terms of hCA I, hCA II, and AChE inhibition effects, respectively) to determine the binding profiles of the series with these enzymes. Additionally, the prediction of ADME profiles of the compounds pointed out that the newly synthesized compounds had desirable physicochemical properties as lead compounds for further studies.

Synthesis and biological evaluation of some new mono Mannich bases with piperazines as possible anticancer agents and carbonic anhydrase inhibitors

New mono Mannich bases, (2-(4-hydroxy-3-((4-substituephenylpiperazin-1-yl)methyl)benzylidene)-2,3-dihydro-1H-inden-1-one), were prepared to evaluate their cytotoxic/anticancer properties and also their inhibitory effects on human carbonic anhydrase I and II isoenzymes (hCA I and II). Amine part was changed as [N-phenylpiperazine (1), N-benzylpiperazine (2), 1-(2-fluorophenyl)piperazine (3), 1-(4-fluorophenyl)piperazine (4), 1-(2-methoxyphenyl)piperazine (5)]. The structure of the synthesized compounds was characterized by ¹H NMR, ¹³C NMR and HRMS spectra. Cytotoxicity results of the series pointed out that the compound 4 had the highest tumor selectivity value (TS: 59.4) possibly by inducing necrotic cell death in series. Additionally, all compounds synthesized showed a good inhibition profile towards hCA I and II isoenzymes with the Ki values between 29.6 and 58.4 nM and 38.1-69.7 nM, respectively. These values were lower than the reference compound AZA. However, it seems that the compounds 4 and 2 can be considered as lead compounds of CA studies with the lowest Ki values in series for further designs.

New azafluorenones with cytotoxic and carbonic anhydrase inhibitory properties: 2-Aryl-4-(4-hydroxyphenyl)-5H-indeno[1,2-b]pyridin-5-ones

New azafluorenones, 2-aryl-4-(4-hydroxyphenyl)-5H-indeno[1,2-b]pyridin-5-ones, were prepared to evaluate their cytotoxic/anticancer properties, also their inhibitory effects on hCA I and II isoenzymes. Aryl part was changed as [phenyl (H1), 4-methylphenyl (H2), 4-methoxyphenyl (H3), 4-fluorophenyl (H4), 4-bromophenyl (H5), 4-chlorophenyl (H6), 3-hydroxyphenyl (H7), and 4-hydroxyphenyl (H8)]. The structure of the synthesized compounds was characterized by ¹H NMR, ¹³C NMR and HRMS spectra. Cytotoxicity results of the series pointed out that the compounds H6 (PSE: 28.0) and H5 (PSE: 27.3), with the highest potency selectivity expression (PSE) value, can be considered as leader compounds of the study in designing novel anticancer agents. Additionally, all azafluorenones synthesized showed a good inhibition profile towards hCA I and II isoenzymes in the range of 54.14-73.72 nM and 67.28-76.15 nM, respectively. The compounds H5 and H6 can be considered for further designs with their cytotoxic and CA inhibitory profiles.

Crystal structure and theoretical study of (2E)-1-[4-hy-droxy-3-(morpholin-4-ylmeth-yl)phen-yl]-3-(thio-phen-2-yl)prop-2-en-1-one

In the title compound, C18H19NO3S, the morpholine ring adopts a chair conformation. The thio-phene ring forms dihedral angles of 26.04 (9) and 74.07 (10)° with the benzene ring and the mean plane of the morpholine ring, respectively. The mol-ecular conformation is stabilized by an O-H⋯N hydrogen bond. In the crystal, mol-ecules are connected through C-H⋯O hydrogen bonds, forming wave-like layers parallel to the ab plane, which are further linked into a three-dimensional network by C-H⋯π inter-actions involving the benzene rings and the methyl-ene H atoms of the morpholine rings.

New anticancer drug candidates sulfonamides as selective hCA IX or hCA XII inhibitors

In this study, new 4-[3-(aryl)-5-substitutedphenyl-4,5-dihydro-1H-pyrazole-1-yl]benzensulfonamides (19-36) were synthesized and evaluated their cytotoxic/anticancer and CA inhibitory effects. According to results obtained, the compounds 34 (4-[5-(2,3,4-trimethoxyphenyl)-3-(thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-yl] benzensulfonamide, Potency-Selectivity Expression (PSE) = 141) and 36 (4-[5-(3,4,5-trimethoxyphenyl)-3-(thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-yl]benzensulfonamide, PSE = 54.5) were found the leader anticancer compounds with the highest PSE values. In CA inhibitory studies, the compounds 36 and 24 (4-[5-(3,4,5-trimethoxyphenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazole-1-yl]benzensulfonamide) were found the leader CA inhibitors depending on selectivity ratios. The compound 36 was a selective inhibitor of hCA XII isoenzyme (hCA I/hCA XII = 1250 and hCA II/hCA XII = 224) while the compound 24 was a selective inhibitor of hCA IX isoenzyme (hCA I/hCA IX = 161 and hCA II/hCA IX = 177). The compounds 24, 34, and 36 can be considered to develop new anticancer drug candidates.

Designing, synthesis and bioactivities of 4-[3-(4-hydroxyphenyl)-5-aryl-4,5-dihydro-pyrazol-1-yl]benzenesulfonamides

In this study, 4-[3-(4-hydroxyphenyl)-5-aryl-4,5-dihydro-pyrazol-1-yl]benzenesulfonamide (1-9) types compounds were synthesized and their chemical structures were confirmed by 1H NMR, 13C NMR and HRMS spectra. Cytotoxic and carbonic anhydrase (CA) inhibitory effects of the compounds were investigated. Cytotoxicity experiments pointed out that compound 4, (4-[5-(4-chlorophenyl)-3-(4-hydroxyphenyl)-4,5-dihydro-pyrazol-1-yl]benzenesulfonamide), exerting the highest tumor selectivity (TS) and potency selectivity expression (PSE) values, can be considered as a lead compound of this study in terms of development of novel anticancer agents. All synthesized sulfonamides showed a good inhibition profile on hCA IX and XII in the range of 53.5-923 nM and 6.2-95 nM, respectively. These compounds were 2.5-13.4 times more selective for the inhibition of hCA XII versus hCA IX, except compound 2 which had similar inhibitory action towards both isoenzymes.

Microwave-assisted synthesis and bioevaluation of new sulfonamides

In this study, 4-[5-(4-hydroxyphenyl)-3-aryl-4,5-dihydro-1H-pyrazol-1-yl]benzenesulfonamide derivatives (8-14) were synthesized for the first time by microwave irradiation and their chemical structures were confirmed by ¹H NMR, ¹³C NMR and HRMS. Cytotoxic activities and inhibitory effects on carbonic anhydrase I and II isoenzymes of the compounds were investigated. The compounds 9 (PSE = 4.2), 12 (PSE = 4.1) and 13 (PSE = 3.9) with the highest potency selectivity expression (PSE) values in cytotoxicity experiments and the compounds 13 (Ki = 3.73 ± 0.91 nM toward hCA I) and 14 (Ki = 3.85 ± 0.57 nM toward hCA II) with the lowest Ki values in CA inhibition studies can be considered as leader compounds for further studies.

Crystal structure of (E)-2-({4-hydroxy-5-methoxy-3-[(4-methyl-1-piperazinyl)methyl]phenyl} methylidene)-1-indanone, C23H26N2O3

C23H26N2O3, triclinic, P1̅ (No. 2), a = 10.6646(19) Å, b = 10.7784(17) Å, c = 11.150(2) Å, α = 67.787(7)°, β = 64.309(7)°, γ = 64.271(7)°, V = 1011.6(3) Å3, Z = 2, R gt(F) = 0.0502, wR ref(F 2) = 0.1481, T = 293 K.

Synthesis and bioactivity studies on new 4-(3-(4-Substitutedphenyl)-3a,4-dihydro-3H-indeno[1,2-c]pyrazol-2-yl) benzenesulfonamides

A series of new 4-(3-(4-substitutedphenyl)-3a,4-dihydro-3H-indeno[1,2-c]pyrazol-2-yl) benzenesulfonamides (7-12) was synthesized starting from 2-(4-substitutedbenzylidene)-2,3-dihydro-1H-inden-1-one (1-6) and 4-hydrazinobenzenesulfonamide. The substituted benzaldehydes from which the key intermediate was prepared by introducing 2- or 4-substituents such as fluorine, hydroxy, methoxy, or the 3,4,5-trimethoxy moieties. The compounds were tested for their cytotoxicity, tumor-specificity and potential as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. The 3,4,5-trimethoxy and the 4-hydroxy derivatives showed interesting cytotoxic activities, which may be crucial for further anti-tumor activity studies, whereas some of these sulfonamides strongly inhibited both human (h) cytosolic isoforms hCA I and II.

Synthesis, cytotoxicity and carbonic anhydrase inhibitory activities of new pyrazolines

A series of polymethoxylated-pyrazoline benzene sulfonamides were synthesized, investigated for their cytotoxic activities on tumor and non-tumor cell lines and inhibitory effects on carbonic anhydrase isoenzymes (hCA I and hCA II). Although tumor selectivity (TS) of the compounds were less than the reference compounds 5-Fluorouracil and Melphalan, trimethoxy derivatives 4, 5, and 6 were more selective than dimethoxy derivatives 2 and 3 as judged by the cytotoxicity assay with the cells both types originated from the gingival tissue. The compound 6 (4-[3-(4-methoxyphenyl)-5-(3,4,5-trimethoxyphenyl)-4,5-dihydro-1H-pyrazol-1-yl] benzene sulfonamide) showed the highest TS values and can be considered as a lead molecule of the series for further investigations. All compounds synthesized showed superior CA inhibitory activity than the reference compound acetazolamide on hCA I, and II isoenzymes, with inhibition constants in the range of 26.5-55.5 nM against hCA I and of 18.9-28.8 nM against hCA II, respectively.

Crystal structure of 1-{4-hy-droxy-3-[(pyrrolidin-1-yl)meth-yl]phen-yl}-3-phenyl-prop-2-en-1-one

In the title compound, C20H21NO2, the pyrrolidine ring adopts an envelope conformation with the N atom at the flap position. The central benzene ring makes dihedral angles of 21.39 (10) and 80.10 (15)° with the phenyl ring and the mean plane of the pyrrolidine ring, respectively. The mol-ecular conformation is stabilized by an intra-molecular O-H⋯N hydrogen bond, which closes an S(6) ring. A weak C-H⋯π inter-action is observed in the crystal.

Synthesis of mono Mannich bases of 2-(4-hydroxybenzylidene)-2,3-dihydroinden-1-one and evaluation of their cytotoxicities

Chalcones and Mannich bases are a group of compounds known for their cytotoxicities. In this study restricted chalcone analogue, compound 2-(4-hydroxybenzylidene)-2,3-dihydroinden-1-one MT1, was used as a starting compound to synthesize new mono Mannich bases since Mannich bases may induce more cytotoxicity than chalcone analogue that they are derived from by producing additional alkylating center for cellular thiols. In this study, cyclic and acyclic amines were used to synthesize Mannich bases. All compounds were tested against Ca9-22 (gingival carcinoma), HSC-2, HSC-3 and HSC-4 (oral squamous cell carcinoma) as tumour cell lines and HGF (gingival fibroblasts), HPC (pulp cells) and HPLF (periodontal ligament fibroblasts) human normal oral cells as non tumour cell lines. Cytotoxicity, selectivity index (SI) values and potency selectivity expression (PSE) values expressed as a percentage were determined for the compounds. According to data obtained, the compound MT8 with the highest PSE value bearing N-methylpiperazine moiety seems to be a good candidate to develop new cytotoxic compounds and is suited for further investigation.

Mannich bases in medicinal chemistry and drug design

The biological activity of Mannich bases, a structurally heterogeneous class of chemical compounds that are generated from various substrates through the introduction of an aminomethyl function by means of the Mannich reaction, is surveyed, with emphasis on the relationship between structure and biological activity. The review covers extensively the literature reports that have disclosed Mannich bases as anticancer and cytotoxic agents, or compounds with potential antibacterial and antifungal activity in the last decade. The most relevant studies on the activity of Mannich bases as antimycobacterial agents, antimalarials, or antiviral candidates have been included as well. The review contains also a thorough coverage of anticonvulsant, anti-inflammatory, analgesic and antioxidant activities of Mannich bases. In addition, several minor biological activities of Mannich bases, such as their ability to regulate blood pressure or inhibit platelet aggregation, their antiparasitic and anti-ulcer effects, as well as their use as agents for the treatment of mental disorders have been presented. The review gives in the end a brief overview of the potential of Mannich bases as inhibitors of various enzymes or ligands for several receptors.