An efficient methodological approach for synthesis of selenopyridines: generation, reactions, anticancer activity, EGFR inhibitory activity and molecular docking studies.

In the present work, we successfully synthesized Se-alkyl selenopyridines 1 and 3, selenopheno[2,3-b]pyridine 2, and bis-selenopyridine 4 derivatives using an eco-friendly method by utilizing NaHSe instead of toxic hydrogen selenide. The effect of the temperature on the reaction was screening at various temperatures. The regiospecific reaction of selenopyridine 1 with bromine afforded an unexpected product 4,6-diamino-5-bromo-2-[(cyanomethyl)selenyl]-pyridine-3-carbonitrile (5), which was cyclized to selenopheno[2,3-b]pyridine (7) by refluxing in the presence of TEA. While its treatment with thiophenol and/or p-chlorothiophenol gave 8a, b. On the other hand, its reaction with aminothiophenol afforded 2-(benzo[d]-thiazol-2-yl)-5-bromoselenopheno[2,3-b]pyridine-3,4,6-triamine (9). Also, N-(2-cyano-4-methyl-5H-1-seleno-3,5,8-triazaacenaphthylen-7-yl)acetamide (11) and a novel series of selenoazo dyes 12a-d were synthesized by treatment of selenopheno[2,3-b]pyridine 2 with acetic anhydride and/or diazonium chlorides of aromatic amines, respectively. Then, we ascertained the potential activity of synthesized compounds against highly metastatic prostate cancer cells (PC-3) and osteosarcoma cells (MG-63) and found that 12a, 12b, 12c, and 12d were more cytotoxic than doxorubicin in both tested cell lines, showing nearly the same anticancer activity with IC50 values ranging from 2.59 ± 0.02 µM to 3.93 ± 0.23 µM. Mechanistically, the most potent compounds 12a and 12b proved to be potent EGFR inhibitors with IC50 values of 0.301 and 0.123 µM, respectively, compared to lapatinib as a positive reference (IC50 = 0.049 µM). Moreover, the docking results are in good agreement with the anticancer activity as well as the EGFR inhibitory activity, suggesting these two compounds as promising EGFR anticancer candidates.

Preparation, Agricultural Bioactivity Evaluation, Structure-Activity Relationships Estimation, and Molecular Docking of Some Quinazoline Compounds.

Quinazoline compounds have gained significant attention in the fields of agriculture and chemistry due to their diverse activities. In this study, we focused on a series of quinazoline derivatives (4a-l). The objectives involved multiple aspects, including preparation, evaluation of their agricultural bioactivity against the maize aphid (Rhopalosiphum maidis), estimation of the structure-activity relationships (SAR), and conducting molecular docking analysis. The results of the agricultural bioactivities revealed that compound (4b) possesses the highest insecticidal activity, and the other compounds have good potential as insecticidal agents. We conducted the SARs and also molecular docking investigation to elucidate the binding modes and interactions of these compounds with target proteins relevant to the agricultural bioactivity. The docking results provided valuable information on the binding affinities and molecular interactions, aiding in the rationalization of the observed bioactivity trends. The enzyme, acetylcholinesterase (AChE), was docked with the 12 synthetic compounds (4a-l). Among these compounds, (4b), (4i), and (4e)exhibited the highest binding affinity, with docking scores (S) of -7.96, -7.83, and -7.73 kcal/mol, respectively. They were followed by compounds (4d) (S = -7.57 kcal/mol), (4c) (S = -7.53 kcal/mol), (4g) (S = -7.34 kcal/mol), (4f) (S = -7.23 kcal/mol), (4h) (S = -7.14 kcal/mol), (4k) (S = -6.61 kcal/mol), (4j) (S = -6.57 kcal/mol), (4a) (S = -6.28 kcal/mol), and finally (4l) (S = -6.01 kcal/mol). These compounds were shown to have a variety of binding interactions within the 2ACE active site, as evidenced by protein-ligand docking configurations. This study gives evidence that those compounds have AChE-inhibitory capabilities and, hence, may be used for AChE-targeting development. Also, the findings in this study highlight the potential of these compounds as agricultural agents and provide valuable insights for the design and development of some quinazoline derivatives with enhanced bioactivity for crop protection.

XRD/DFT, Hirshfeld surface analysis and molecular modelling simulations for unfolding reactivity of newly synthesized vanillin derivatives: excellent optical, NLO and protein binding efficiency.

New vanillin derivatives, namely, ethyl (4-formyl-2-methoxyphenoxy)acetate (2a) and 2-(4-formyl-2-methoxyphenoxy)-N-phenylacetamide (2b), respectively, were synthesized and characterized by NMR (1H and 13C), IR, mass spectra and confirmed by single-crystal X-ray analysis. Hirshfeld surface (HS) analysis was performed to probe intra- and intermolecular interactions and surface reactivity. 2D fingerprint plots (FP) were used to study the nature and percentage contribution of intermolecular interactions leading to the formation of the crystal unit. Density functional theory (DFT) simulations were used to obtain the electronic structure and reactivity of the new molecules. Natural population analysis (NPA) and frontier molecular orbital (FMO) calculations reveal significant charge transfer and a reduced HOMO-LUMO gap up to 4.34 eV for 2b. Bader's quantum theory of atoms in molecules (QTAIM) study is utilized to understand the surface topological and bonding nature of 2a and 2b. The performed molecular electrostatic potential (MESP) and density of states (DOS) study further suggest sites likely to be attractive to incoming reagents. At the same time, hyperpolarizability (ßo) is used to characterize the nonlinear optical properties, and TD-DFT study shows the excitation energy and absorption behavior. In silico studies were performed, including docking, binding free energies (MMBGSA) and molecular dynamics simulations. Compounds 2a and 2b were docked with RdRp of SARS-Cov-2, and the MMBGSA for 2a and 2b were -30.70 and -28.47 kcal/mol, respectively, while MD simulation showed the stability of protein-ligand complexes.Communicated by Ramaswamy H. Sarma.

Utility of arylglyoxal hydrates in synthesis of 4-aroyl-[1,3,5]triazino[1,2-a]benzimidazol-2(1H)-imines and 5-aryl-2-phenyl-4H-imidazol-4-imines.

Nucleophilic substitution reaction for arylglyoxal hydrates (AGs-hydrate) was studied via their reaction with some mono- and multi-nucleophilic reagents in the presence of sodium ethoxide as basic catalyst. Thus, reaction of phenylglyoxal hydrate (1a) with hydrogen sulfide and/or ammonium acetate afforded the corresponding 2-hydroxy-2-mercapto-1-phenylethanone (2) and 2-oxo-2-phenylethanimidamide (3), respectively. Heterocyclization reaction of AGs-hydrate 1a-f with 1-(1H-benzimidazol-2-yl)guanidine (4) gave 4-aroyl-[1,3,5]triazino[1,2-a]benzimidazol-2(1H)-imines 5a-f. Also, a series of 5-aryl-2-phenyl-4H-imidazol-4-imines 7a-d was synthesized via one-pot multicomponent reaction of AGs-hydrate 1a-d, benzonitrile (6) and ammonium acetate. Imidazole-4-imines 7a-d can be also prepared using other route via multicomponent reaction of AGs-hydrate 1a-d, benzenecarboximidamide acetate (8) and ammonium acetate.

Crystal structure of N-[4-amino-5-cyano-6-(methyl-sulfan-yl)pyridin-2-yl]-2-chloro-acetamide.

In the title compound, C9H9ClN4OS, the dihedral angle between the acetamide moiety and the pyridine ring is 4.83 (12)°. The O=C-C-Cl torsion angle is 46.4 (3)° and an intra-molecular C-H⋯O inter-action generates an S(6) ring. In the crystal, mol-ecules are linked by N-H⋯O, N-H⋯N and C-H⋯N hydrogen bonds, generating sheets lying parallel to (120).

Crystal structure of N-[4-amino-5-cyano-6-(methyl-sulfan-yl)pyridin-2-yl]acetamide hemihydrate.

The title compound, C9H10N4OS·0.5H2O, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit, together with a water mol-ecule of crystallization. The acetamide moiety, which has an extended conformation, is inclined to the pyridine ring by 7.95 (16)° in mol-ecule A and by 1.77 (16)° in mol-ecule B. In the crystal, the A and B mol-ecules are linked by two N-H⋯Ocarbon-yl hydrogen bonds, forming a dimer. The dimers are linked via N-H⋯N hydrogen bonds, forming ribbons that are linked by N-H⋯Owater hydrogen bonds to form sheets parallel to (110). The sheets are linked by O-H⋯N hydrogen bonds, forming slabs, and between the slabs there are weak slipped parallel π-π inter-actions [inter-centroid distance = 3.734 (2) Å, inter-planar distance = 3.3505 (11) Šand slippage = 1.648 Å], forming a three-dimensional structure.

Crystal structure of 4,6-di-amino-2-(methyl-sulfan-yl)pyridine-3-carbo-nitrile.

The title pyrimidine derivative, C7H8N4S, is essentially planar, with a maximum deviation of 0.029 (2) Šfrom the mean plane of the non-H atoms. In the crystal, mol-ecules are linked by an inter-molecular bifurcated N-H⋯N hydrogen bond between the cyano N atom and the two amino groups, an N-H⋯N hydrogen bond between the two amino groups and a weak C-H⋯π inter-action, forming a three-dimensional network.

Crystal structure of N-[4-amino-5-cyano-6-(methyl-sulfan-yl)pyridin-2-yl]-2-(cyclo-hexyl-sulfan-yl)acetamide.

In the title mol-ecule, C15H20N4OS2, the acetamido fragment is nearly coplanar with the pyridyl ring [C-N-C-C torsion angle = -4.1 (2)°], while the cyclo-hexyl-sulfanyl portion protrudes from this plane [N-C-C-S torsion angle = -40.8 (6)°]. In the crystal, alternating pairwise N-H⋯O and N-H⋯N hydrogen bonds across inversion centres form chains along [101], which are associated into stepped layers via offset π-π stacking between pyridyl rings [centroid-centroid distance = 3.566 (1) Å]. The cyclo-hexyl group and the two atoms of the S-C bond attached to it are disordered over two sets of sites with site-occupancy factors of 0.8845 (18) and 0.1155 (18).

Crystal structure of 4,6-di-amino-2-sulfanyl-idene-1,2-di-hydro-pyridine-3-carbo-nitrile.

The title compound, C6H6N4S, crystallizes with two independent mol-ecules, A and B, in the asymmetric unit. Both independent mol-ecules are almost planar [maximum deviations of 0.068 (6) Šin mol-ecule A and 0.079 (6) Šin mol-ecule B]. In the crystal, mol-ecules A and B are linked by N-H⋯S, N-H⋯N and C-H⋯S hydrogen bonds, forming a three-dimensional network.

Ethyl 2-[({[4-amino-5-cyano-6-(methyl-sulfan-yl)pyridin-2-yl]carbamo-yl}meth-yl)sulfan-yl]acetate monohydrate.

The title compound, C13H16N4O3S2·H2O, crystallizes in a 'folded' conformation with the ester group lying over the carbamoyl moiety, with one solvent water mol-ecule. The mol-ecular conformation is stabilized by an intra-molecular C-H⋯O hydrogen bond, and an N-H⋯O hydrogen-bonding inter-action involving the lattice water mol-ecule. The packing involves N-H⋯N, N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds and consists of tilted layers running approximately parallel to the c axis, with the ester groups on the outer sides of the layers and with channels running parallel to (101).

3,4,6-Tri-amino-N-phenyl-thieno[2,3-b]pyridine-2-carboxamide.

In the title compound, C14H13N5OS, the dihedral angle between the fused ring system (r.m.s. deviation = 0.028 Å) and the phenyl ring is 48.24 (4)°. The mol-ecule features both an intra-molecular N-H⋯O and an N-H⋯N hydrogen bond. In the crystal, mol-ecules are linked by N-H⋯O and N-H⋯N hydrogen bonds, generating a three-dimensional network. A weak N-H⋯π inter-action is also observed.