Synthesis of 4,5,6,7-tetrahydrothieno[3,2-c]pyridines and comparison with their isosteric 1,2,3,4-tetrahydroisoquinolines as inhibitors of phenylethanolamine N-methyltransferase

Crystal-structure determination and Hirshfeld surface analysis of two new thio-phene derivatives: (E)-N-{2-[2-(benzo[b]thio-phen-2-yl)ethen-yl]-5-fluoro-phen-yl}benzene-sulfonamide and (E)-N-{2-[2-(benzo[b]thio-phen-2-yl)ethen-yl]-5-fluoro-phen-yl}-N-(but-2-yn-1-yl)benzene-sulfonamide

In the title compounds, C22H16FNO2S2 (I) and C26H20FNO2S2 (II), the benzo-thio-phene rings are essentially planar with maximum deviations of 0.009 (1) and 0.001 (1) Å for the carbon and sulfur atom in compounds I and II, respectively. In I, the thio-phene ring system is almost orthogonal to the phenyl ring attached to the sulfonyl group, with a dihedral angle of 77.7 (1)°. In compound I, the mol-ecular structure is stabilized by weak C-H⋯O intra-molecular inter-actions formed by the sulfone oxygen atoms, which generate two S(5) ring motifs. In the crystal of I, N-H⋯O hydrogen bonds link the mol-ecules into R 2 2(8) rings, which are connected into a C(10) chain via C-H⋯F hydrogen bonds. Inter-molecular C-H⋯π inter-actions are also observed. In compound II, the mol-ecules are linked via C-H⋯O and C-H⋯F hydrogen bonding, generating infinite C(11) and C(13) chains running parallel to [010].

The synthesis, crystal structure and Hirshfeld surface analysis of the thio-phene derivatives 5-(phenyl-sulfon-yl)-5,6-di-hydro-benzo[4,5]thieno[3,2-j]phenanthridine and (E)-N-{2-[2-(benzo[b]thiophen-2-yl)ethenyl]phen-yl}-N-(prop-2-yn-1-yl)benzene-sulfonamide

In both of the title compounds, C₂₆H₁₉NO₂S₂, (I), and C₂₅H₁₉NO₂S₂, (II), the benzo-thio-phene rings are essentially planar with maximum deviations of 0.026 (1) and -0.016 (1) Å for the carbon and sulfur atoms in compounds (I) and (II), respectively. In (I), the thio-phene ring system is almost orthogonal to the phenyl ring attached to the sulfonyl group, subtending a dihedral angle of 88.1 (1)°, and the di-hydro-pyridine ring adopts a screw-boat conformation. In both compounds, the mol-ecular structure is consolidated by weak C-H⋯O intra-molecular inter-actions formed by the sulfone oxygen atoms, which generate S(5) ring motifs. In the crystal of II, mol-ecules are linked via C-H⋯O hydrogen bonds, generating C(7) chains running along the [100] direction. No significant inter-molecular inter-actions are observed in I.

Design, Synthesis, Molecular Docking and Biological Studies of New Heterocyclic Compounds Derived from -Diketonesas Novel EGFR and Pim-1 Inhibitors Endowed with Antitumor Activity

BACKGROUND

Cancer is a disease illustrated by a shift in the controlled mechanisms that control both cell proliferation and differentiation. It is regarded as a prime health problem worldwide, leading cause of human death-rate exceeded only by cardiovascular diseases. Many reported work was concerned with the discovery of new antitumor compounds this encourage us to synthesis new anticancer agents.

OBJECTIVE

In this work, we are aiming to synthesize target molecules from 1,3-dicarbonyl compounds through many heterocyclization reactions.

METHOD

The reaction of either 4-methylaniline (1a) or 1-naphthylamine (1b) with diethyl malonate (2) gave the anilide derivatives 3a and 3b, respectively. The latter products underwent a series of heterocyclization reactions to give the pyridine, pyran andthiazole derivatives which confirmed with the required spectral data.

RESULTS

Thein-vitro antitumor evaluations of the newly synthesized products against four cancer cell lines MCF-7, NCI-H460, SF-268 and WI 38 as normal cell line were screened and the data revealed that compounds 11a, 18b, 18c and 20d showed high antitumor activity and 20dindividualize with potential antitumor activity towards cell lines with lowest cytotoxicity effect. Both EGFR and PIM-1 enzyme inhibition were investigated for the compound 20d and his inhibition effect was promising for each enzyme showing IC50=45.67 ng and 553.3 ng for EGFR and PIM-1, respectively.

CONCLUSION

Molecular docking results of compound 20d showed a strong binding interactions on both enzymes, where, good binding modes obtained on case of EGFR, which closely similar to the binding mode of standard Erlotinib. While, 20d showed complete superimposition binding interactions with VRV-cocrystallized ligand of PIM-1 that may expounds the in-vitro antitumor activity.

Synthetic Approaches for Piperidone-Based Templates as Scaffolds to Access Chirally Enriched Donepezil Analogues

A concise and high-yielding double aza-Michael reaction is presented as an atom-efficient method to access chiral 2-substituted 4-piperidone building blocks from divinyl ketones. The piperidones were further converted into analogues of donepezil, an acetylcholinesterase inhibiting drug used in the treatment of Alzheimer's disease. The donepezil analogues were obtained as inseparable diastereomeric mixtures with resolved stereochemistry in position 2 of the piperidine ring. Biological evaluation of the acetylcholinesterase inhibition by these analogues provides a new insight into structure-activity relationship studies with regard to donepezil's piperidine moiety toward stereochemical enhancement.

Late stage trifluoromethylthiolation strategies for organic compounds

Substitution by the CF3S group allows for an increase in lipophilicity and electron-withdrawing properties along with an improvement in the bioavailability of medicinal targets; consequently, the late stage introduction of CF3S moieties into medicinal scaffolds is a sought-after strategy in synthetic organic chemistry. Different newly-developed electrophilic and nucleophilic reagents are used to effect the trifluoromethylthiolation of (hetero)aromatic compounds, aliphatic compounds (alkyl, alkenyl, alkynyl substrates), the trifluoromethylthiolation at the α- and β-carbonyl positions, and heteroatoms (N- and S-). Such reactions can involve homolytic substitutions, or functional-group substitutions (ipso). Addition reactions of electrophilic reagents to double and triple bonds followed by ring-cyclizations will be shown to yield relevant CF3S-substituted heteroaromatic compounds with relevant pharmacological action.

Crystal structure of (4-meth-oxy-phen-yl)[(4-meth-oxy-phen-yl)phospho-nato]dioxidophosphate(1-) 2-amino-6-benzyl-3-eth-oxy-carbon-yl-4,5,6,7-tetra-hydro-thieno[2,3-c]pyridin-6-ium

The asymmetric unit of the title mol-ecular salt, C17H21N2O2S(+)·C14H15O7P2 (-), comprises two cations and two anions. Each cation features an intra-molecular N-H⋯O hydrogen bond, which closes an S(6) ring; in each case the hydro-pyridine ring adopts a half-chair conformation. In the anions, the dihedral angles between the aromatic rings are 64.1 (2) and 54.9 (2)°. In each case, the diphosphate groups are close to eclipsed [C-P⋯P-C pseudo-torsion angles = 11.6 (2) and -19.3 (2)°]. One of the meth-oxy groups in each anion is disordered over two orientations in a 0.539 (18):0.461 (18) ratio in one anion and 0.82 (2):0.18 (2) in the other. In the crystal, O-H⋯O and N-H⋯O hydrogen bonds link the components into [100] chains. Numerous C-H⋯O inter-actions cross-link the chains into a three-dimensional network.

Synthetic studies of centromere-associated protein-E (CENP-E) inhibitors: 1.Exploration of fused bicyclic core scaffolds using electrostatic potential map

Centromere-associated protein-E (CENP-E), a mitotic kinesin that plays an important role in mitotic progression, is an attractive target for cancer therapeutic drugs. For the purpose of developing novel CENP-E inhibitors as cancer therapeutics, we investigated a fused bicyclic compound identified by high throughput screening, 4-oxo-4,5-dihydrothieno[3,4-c]pyridine-6-carboxamide 1a. Based on this scaffold, we designed inhibitors for efficient binding at the L5 site in CENP-E utilizing homology modeling as well as electrostatic potential map (EPM) analysis to enhance CENP-E inhibitory activity. This resulted in a new lead, 5-bromoimidazo[1,2-a]pyridine 7, which showed potent CENP-E enzyme inhibition (IC50: 50nM) and cellular activity with accumulation of phosphorylated histone H3 in HeLa cells. Our homology model and EPM analysis proved to be useful tools for the rational design of CENP-E inhibitors.

Comparison of enveloping distribution sampling and thermodynamic integration to calculate binding free energies of phenylethanolamine N-methyltransferase inhibitors

The relative binding free energy between two ligands to a specific protein can be obtained using various computational methods. The more accurate and also computationally more demanding techniques are the so-called free energy methods which use conformational sampling from molecular dynamics or Monte Carlo simulations to generate thermodynamic averages. Two such widely applied methods are the thermodynamic integration (TI) and the recently introduced enveloping distribution sampling (EDS) methods. In both cases relative binding free energies are obtained through the alchemical perturbations of one ligand into another in water and inside the binding pocket of the protein. TI requires many separate simulations and the specification of a pathway along which the system is perturbed from one ligand to another. Using the EDS approach, only a single automatically derived reference state enveloping both end states needs to be sampled. In addition, the choice of an optimal pathway in TI calculations is not trivial and a poor choice may lead to poor convergence along the pathway. Given this, EDS is expected to be a valuable and computationally efficient alternative to TI. In this study, the performances of these two methods are compared using the binding of ten tetrahydroisoquinoline derivatives to phenylethanolamine N-transferase as an example. The ligands involve a diverse set of functional groups leading to a wide range of free energy differences. In addition, two different schemes to determine automatically the EDS reference state parameters and two different topology approaches are compared.

Discovery of novel human phenylethanolamine N-methyltransferase (hPNMT) inhibitors using 3D pharmacophore-based in silico, biophysical screening and enzymatic activity assays

With the aid of receptor-oriented pharmacophore-based in silico screening, we established three pharmacophore maps explaining the binding model of hPNMT and a known inhibitor, SK&F 29661 (Martin et al., 2001). The compound library was searched using these maps. Nineteen selected candidate inhibitors of hPNMT were screened using STD-NMR and fluorescence experiments. An enzymatic activity assay based on HPLC was additionally performed. Consequently, three potential hPNMT inhibitors were identified, specifically, 4-oxo-1,4-dihydroquinoline-3,7-dicarboxylic acid, 4-(benzo[d][1,3]dioxol-5-ylamino)-4-oxobutanoic acid, and 1,4-diaminonaphthalene-2,6-disulfonic acid. These novel inhibitors were retrieved using Map II comprising one hydrogen bond acceptor, one hydrogen bond donor, one lipophilic feature, and shape constraints, including a hydrogen bond between Lys57 of hPNMT and a hydrogen bond donor of the inhibitor, and stacked hydrophobic interactions between the side-chain of Phe182 and an aromatic region of the inhibitor. Water-mediated interactions between Asn267 and Asn39 of hPNMT and the amide or amine group of three potent inhibitors were additional important features for hPNMT activity. The binding model presented here may be applied to identify inhibitors with higher potency. Moreover, our novel compounds are valuable candidates for further lead optimization of PNMT inhibitors.