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The crystal structure and topology analyses of a new bromo-Mn(II) complex with 2,4-bis(3,5dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (MBPT) were reported. Its structure was confirmed using single-crystal X-ray diffraction to create the formula [Mn(MBPT)Br(H2O)2]ClO4. Its crystal system was monoclinic and its space group was p21. The Mn(II) was coordinated with MBPT as a NNN-pincer ligand, with one bromide ion in the equatorial plane. The two axial terminals were occupied by two trans water molecules. H…H, N…H, Br…H, C…H and O…H were the predominant intermolecular contacts, while Br…H, O…H and C…O were the significant contacts based on Hirshfeld analysis. Moreover, anion–ᴨ interaction was found between C(s-triazine) and O(perchlorate). This complex had better antioxidant activity than the free ligand (MBPT). In addition, the cytotoxicity of the [Mn(MBPT)Br(H2O)2]ClO4 complex showed better results against HepG-2 and MCF-7 cells, recording IC50 values of 31.11 ± 2.04 and 50.05 ± 2.16 µM, respectively, compared to the free ligand (IC50 = 671.44 ± 21.41 and 1113.55 ± 29.77 µM). In comparison to cis-platin as a reference drug, the IC50 values were 63 and 80 μM, respectively, which indicated the promising anticancer activity of the studied compound against both cell lines. In terms of the safety of normal cells, the Mn(II) complex recorded a high IC50 value of 359.10 ± 8.72 µM against the WI-38 non-cancerous cell line. The complex showed better activity towards Staphylococcus aureus, Bacillus subtilis, and Proteus vulgaris relative to the free MBPT, but had low to moderate activity compared to Gentamycin as an antibacterial positive control.

The molecular and supramolecular structures of some M(II) complexes (M = Co, Mn, Cu, Ni, Zn) with a hydrazone-s-triazine ligand (BMPyTr) were discussed based on single crystal X-ray diffraction (SCXRD), Hirshfeld and DFT analyses. A new Co(II) complex of the same ligand was synthesized and its structure was confirmed to be [Co(BMPyTr)Cl2]·H2O based on FTIR and UV–Vis spectra, elemental analysis and SCXRD. The geometry around Co(II) was a distorted square pyramidal configuration (τ5 = 0.4), where Co(II) ion is coordinated to one NNN-tridentate ligand (BMPyTr) and two Cl- ions. A Hirshfeld analysis indicated all potential contacts within the crystal structure, where the percentages of O⋯H, N⋯H, C⋯H, and H⋯H contacts in one unit were 11.2, 9.3, 11.4, and 45.9%, respectively, while the respective values for the other complex unit were 10.3, 8.8, 10.6, and 48.0%. According to DFT calculations, the presence of strongly coordinating anions, such as Cl-, in addition to the large metal ion size, were found to be the main reasons for the small M-BMPyTr interaction energies in the cases of [Mn(BMPyTr)Cl2] (260.79 kcal/mol) and [Co(BMPyTr)Cl2]·H2O (307.46 kcal/mol) complexes. Interestingly, the Co(II) complex had potential activity against both Gram-positive (S. aureus and B. subtilis) and Gram-negative (E. coli and P. vulgaris) bacterial strains with inhibition zone diameters of 13, 15, 16, and 18 mm, respectively. Also, the new [Co(BMPyTr)Cl2]·H2O (IC50 = 131.2 ± 6.8 μM) complex had slightly better cytotoxic activity against HCT-116 cell line compared to BMPyTr (145.3 ± 7.1 μM).

A new series of spirooxindoles based on benzimidazole, triazole, and isatin moieties were synthesized via a [3+2] cycloaddition reaction protocol in one step. The single X-ray crystal structure of the intermediate triazole-benzimidazole 4 was solved. The new chemical structures of these spirooxindole molecules have been achieved for the first time. The final synthesized chemical architecture has differently characterized electronic effects. An MEDT study of the key 32CA reaction between in situ generated azomethine ylide (AY) and chalcones explained the low reaction rates and the total selectivities observed. The supernucleophilic character of AY and the strong electrophilicity of chalcones favor these reactions through a highly polar two-stage one-step mechanism in which bond formation at the β-conjugated carbon of the chalcones is more advanced. The present combined experimental and theoretical study reports the synthesis of new spirooxindoles with potential biological activities and fully characterizes the molecular mechanisms for their formation through the key 32CA reaction step.

Two novel silver(I) coordination polymers, [Ag(4BP)(SCN)]n (1) and {(4BPH)+[Ag(SCN)2]−}n (2) (4BP = 4-benzoyl pyridine), have been synthesized. The two complexes were prepared using almost the same reagents, which were AgNO3, 4BP and NH4SCN. The only difference was the presence of 1:1 (v/v) HNO3 in the synthesis of 2. In the two complexes, the Ag(I) has distorted tetrahedral coordination geometry. The structure of both complexes and the involvement of the thiocyanate anion as a linker between the Ag(I) centers were confirmed using single-crystal X-ray diffraction. 4BP participated as a monodentate ligand in the coordination sphere of complex 1, while in 2 it is found protonated (4BP-H)+ and acts as a counter ion, which balances the charge of the anionic [Ag(SCN)2]− moiety. The thiocyanate anion shows different coordination modes in the two complexes. In complex 1, the thiocyanate anion exhibits a µ1,1,3 bridging mode, which binds three Ag(I) ions to build a boat-like ten-membered ring structure leading to a two-dimensional coordination polymer. In 2, there are mixed µ1,1 and µ1,3 bridging thiocyanate groups, which form the one-dimensional polymeric chain running in the a-direction. Several interactions affected the stability of the crystal structure of the two complexes. These interactions were examined using Hirshfeld surface analysis. The coordination interactions (Ag-S and Ag-N) have a great impact on the stability of the polymeric structure of the two complexes. Additionally, the hydrogen-bonding interactions are crucial in the assembly of these coordination polymers. The O…H (10.7%) and C…H (34.2%) contacts in 1 as well as the N···H (15.3%) and S···H (14.9%) contacts in 2 are the most significant. Moreover, the argentophilic interaction (Ag…Ag = 3.378 Å) and π- π stacking play an important role in the assembly of complex 2.

The synthesis and X-ray crystal structure analyses of the azido complex [Zn(N3)(Arg)2](N3)·3H2O, where Arg is L-arginine, were presented. The molecular structure of the complex was further studied using FT-IR spectra as well as atoms in molecules (AIM) theory. An analysis of the crystal data indicated monoclinic crystal system and P21 space group with a = 13.0283(5) Å, b = 15.2032(7) Å, c = 13.3633(6) Å, β = 114.3580(10)°, V = 2411.28(18) Å3, and Z = 4. Two of the [Zn(N3)(Arg)2](N3)·3H2O formulae represent the asymmetric unit of this complex where the geometric parameters of both units are slightly different. In [Zn(N3)(Arg)2](N3)·3H2O, the central Zn(II) ion is penta-coordinated with two Arg molecules as a bidentate ligand and one terminally coordinated azide ion. Each of the two Arg molecules are located trans to one another and coordinated with the Zn(II) via the N and O atoms of the amino and carboxylate groups, respectively. Hence, Zn(II) is five-coordinated and has a distorted square pyramidal coordination geometry. The supramolecular structure of the [Zn(N3)(Arg)2](N3)·3H2O complex was inspected using the Hirshfeld analysis. The O···H (26.6–28.4%), H···H (32.3–35.3%), and N···H (30.4–34.0%) contacts are the most significant interactions in the crystal structure of the [Zn(N3)(Arg)2](N3)·3H2O complex. The Zn–N, and Zn–O bonds have slight covalent interactions based on the AIM study.

The complex [Co(L)(H2O)4](NO3)2 of (E)-4-(2-(3-methyl-5-oxo-1-(pyridin-2-yl)-1H-pyrazol-4(5H)-ylidene)hydrazinyl)-N-(pyrimidin-2-yl)benzenesulfonamide (L) was synthesized via the self-assembly technique. Its molecular and supramolecular structures were analyzed using FTIR, elemental analyses, and single-crystal X-ray diffraction, as well as Hirshfeld calculations. This complex crystallized in the triclinic space group P1¯ with Z = 2. The crystallographic asymmetric unit comprised one complex cation and two nitrate counter anions. This complex had distorted octahedral geometry around the Co(II) ion. Numerous intermolecular interactions affecting the molecular packing of this complex were conformed using Hirshfeld investigations. The most significant contacts for the cationic inner sphere [Co(L)(H2O)4]2+ were O···H (38.8%), H···H (27.8%), and N···H (9.9%). On the other hand, the main interactions for the counter NO3¯ ions were the O···H (79.6 and 77.8%), O···N (8.0%), and O···C (9.1%). A high propensity for making interactions for each atom pair in the contacts O…H, N…C, N…H, and C…C was revealed by enrichment ratio values greater than 1. The antibacterial efficacy of the complex and the free ligand were assessed. The free ligand had higher antibacterial activity (MIC = 62.5–125 µg/mL) than the [Co(L)(H2O)4](NO3)2 complex (MIC ≥ 250 µg/mL) versus all the studied bacteria.

The pandemic of COVID-19, caused by SARS-CoV-2, has globally affected the human health and economy. Since the emergence of the novel coronavirus SARS-CoV-2, the life-threatening virus continues to mutate and evolve. Irrespective of acquired natural immunity and vaccine-induced immunity, the emerging multiple variants are growing exponentially, crossing the territorial barriers of the modern world. The rapid emergence of SARS-CoV-2 multiple variants challenges global researchers regarding the efficacy of available vaccines and variant transmissibility. SARS-CoV-2 surface-anchored S-protein recognizes and interacts with the host-cell ACE2, facilitating viral adherence and entrance into the cell. Understanding the interfacial interactions between the spike protein of SARS-CoV-2 variants and human ACE2 receptor is important for the design and development of antiviral therapeutics against SARS-CoV-2 emerging variants. Despite extensive research, the crucial determinants related to the molecular interactions between the spike protein of SARS-CoV-2 variants and host receptors are poorly understood. Thus, in this study, we explore the comparative interfacial binding pattern of SARS-CoV-2 spike RBD of wild type, Delta, and Omicron with the human ACE2 receptor to determine the crucial determinants at the atomistic level, using MD simulation and MM/GBSA energy calculations. Based on our findings, the substitution of Q493R, G496S, Q498R, and Y505H induced internal conformational changes in Omicron spike RBD, which leads to higher binding affinity than Delta spike RBD with the human ACE2 receptor, eventually contributing to higher transmission and infectivity. Taken together, these results could be used for the structure-based design of effective antiviral therapeutics against SARS-CoV-2 variants.

5-(1H-Indol-2-yl)-4-phenyl-2,4-dihydro-3H-1,2,4-triazole-3-thione 1a and 4-(4-chlorophenyl)-5-(1H-indol-2-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione 1b were galactosylated in the presence of NaHCO3 in ethanol to produce S-galactosides 3,4, whereas, in the presence of K2CO3 in acetone they produced a mixture of S- and N-galactosides 3-6 with a higher yield of S-galactosides over the respective N-galactosides. Improvement in the yields of N-galactosides was produced by thermal migration of the galactosyl moiety from sulfur to nitrogen using fusion. β-Stereoselectivity of galactosylation was determined using the coupling constant value 3J1,2, which exceeded 9.0 Hz in all prepared galactosides. The precursors 1a and 1b alkylated with 3-bromopropan-1-ol 7 in K2CO3 and acetone produced the S-alkylated products 8 and 9, respectively. Structural determinations of new compounds 5 and 9 are presented. The phenyl and indole moieties were found to be twisted from the triazole ring mean in both compounds. For compound 5, the twist angles were 66.24° and 18.86°, respectively, while the corresponding values for 9 were in the ranges of 73.15–77.29° and 13.96–20.70°, respectively. Hence, the crystal system of 9 is triclinic while the space group is P-1. Detailed analysis of the intermolecular interactions in the crystal structure of 5 is presented using Hirshfeld calculations. The O…H, N…H, C…H, and S…H contacts appeared as red spots in the dnorm Hirshfeld surface indicating short distance intermolecular interactions. Their percentages were estimated based on the decomposition of the fingerprint plot to be 25.6, 2.4, 14.0, and 6.3%, respectively.

The present synthetic strategy involves the synthesis of indolyl-triazolo-thiadiazole heterocyclic ring systems 8–13 from the condensation of 4-amino-5-(1H-indol-2-yl)-3H-1,2,4-triazole-3-thione 1 with the aromatic carboxylic acid derivatives 2–7 in presence of POCl3 for 1 h. All compounds were obtained in very good yields and have been well-characterized using spectroscopic techniques. Exclusively, good quality crystals from the target organic hybrid 8-(1H-indol-2-yl)-5-(p-tolyl)-[1,2,4]triazolo [3,4-b][1,3,4]thiadiazole 9 were obtained and found suitable for X-ray single crystal diffraction measurement, which is used to confirm and analyze the molecular and supramolecular structure aspects of 9. The solid-state structure of the synthesized molecule 9 agrees very well with other characterizations. The packing of 9 is dominated by the N…H, S…H, C…C and S…C non-covalent interactions, which agree with the Hirshfeld surface analysis. The percentages of these contacts are calculated to be 20.3%, 5.4%, 9.4% and 4.3%, respectively.

Two new Co(II) and Cu(II) azido complexes with 4-picoline (4-Pic) and pyridine-2-carboxaldoxime (HAld) were synthesized by self-assembly of the organic ligand and the M(II) nitrate in the presence of azide as a co-ligand. Their structures were determined to be [Co(4-Pic)4(H2O)(N3)]NO3*H2O*4-Pic (1) and [Cu(HAld)(Ald)(N3)] (2) using X-ray single crystal diffraction. In complex 1, the coordination geometry is a slightly distorted octahedron with a water molecule and azide ion located trans to one another. On the other hand, complex 2 has a distorted square pyramid CuN5 coordination sphere with N-atoms of the organic ligand as a basal plane and azide ion as apical. All types of intermolecular contacts and their contributions in the molecular packing were analyzed using Hirshfeld analysis. The intermolecular contacts, H…H (53.9%), O…H (14.1%), N…H (11.0%) and H…C (18.8%) in 1, and H…H (27.4%), N…H (27.7%), O…H (14.7%) and H…C (13.6%) in 2 have the largest contributions. Of all the contacts, the O…H, N…H and C…C interactions in 2 and the O…H, N…H and H…C in 1 are apparently shorter than the van der Waals radii sum of the interacting atoms. Atoms in molecules (AIM) topological parameters explained the lower symmetry of the coordinated azide in 1 than 2.

The novel hydrazone-containing thieno[2,3-d]pyrimidine, namely, N′-(1,3-dioxo-1,3-dihydro-2H-inden-2-ylidene)-2-(4-oxo-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-3(4H)-yl)acetohydrazide 4 was synthesized in a very good yield from the reaction of the triketoester 1 or ninhydrin 2 with the exocyclic acetohydrazide 3 in methanol. Good-quality crystals of 4 were obtained by recrystallization of the compound from the DMF/MeOH solvent mixture. The target product 4 crystallized in the triclinic crystal system and P-1 space group. The topology analysis of molecular packing indicated that the H…H (30.4%), O…H (22.0%) and H…C (17.0%) contacts are the most dominant intermolecular interactions in the crystal of 4, while the O…H, N…H, H…C, N…C, O…C, C…C and O…O are the only contacts which have shorter interaction distances than the vdWs radii sum of the interacting atoms. The structure of 4 is optimized and the calculated structure showed good agreement with the experimental one. Additionally, MEP, HOMO, LUMO and the reactivity descriptors were calculated.

Aspects of the molecular and supramolecular structure of the new dinuclear [Ag(L)(NO3)]2 complex, where L is 2-((E)-(((E)-1-(thiazol-2-yl)ethylidene)hydrazono)methyl)phenol, were discussed. The complex was crystallized in the monoclinic crystal system and P21/n space group. The unit cell parameters are a = 10.3274(2) Å, b = 11.4504(3) Å, c = 12.7137(3) Å and β = 108.2560(10)°. The asymmetric unit comprised one [Ag(L)(NO3)] formula in which the azine and nitrate ligand groups act as NN- and OO-bidentate chelates, respectively. The coordination environment of the Ag(I) is completed by one weak Ag-O bond with another [Ag(L)(NO3)] unit, leading to the dinuclear formula [Ag(L)(NO3)]2. This was clearly revealed by Hirshfeld analysis. Additionally, the Ag…C, O…H and C…C intermolecular interactions played an important role in the molecular packing of the studied complex. The antimicrobial, antioxidant and cytotoxic activities of the [Ag(L)(NO3)]2 complex and the free ligand (L) were discussed. While the [Ag(L)(NO3)]2 complex showed very weak antioxidant activity, the results of the antifungal and cytotoxic activities were promising. The inhibition zone diameters (IZD) and the minimum inhibitory concentration (MIC) values were determined to be 31 mm and 20 μg/mL, respectively, against A. fumigatus, which is compared to 17 mm and 156 μg/mL, respectively, for the positive control Ketoconazole. Generally, the Ag(I) complex has better antimicrobial activities than the free ligand against all microbes except for S. aureus, where the free ligand has higher activity. Additionally, the IC50 value against colon carcinoma (HCT-116 cell line) was determined to be 12.53 ± 0.69 µg/mL, which is compared to 5.35 ± 0.49 µg/mL for cis-platin. Additionally, the Ag(I) complex displays better cytotoxicity than the free ligand (L) (242.92 ± 8.12 µg/mL).

An unexpected trinuclear Cu(II)–thiazolidine complex has been synthesized by mixing CuCl2·2H2O with the Schiff base ligand, 1-(((4,5-dihydrothiazol-2-yl)ethylidene)hydrazono)methyl)phenol L, in ethanol. Unexpectedly, the reaction proceeded via the hydrolysis of the Schiff base L, followed by cyclization to afford 3-methyl-5,6-dihydrothiazolo[3,2-c][1,2,3]triazole (La), then complexation with the Cu(II) salt, forming the trinuclear [Cu3(La)4(Cl)6] complex. The complex was characterized by means of FTIR spectra, elemental analysis, and X-ray crystallography. In the trinuclear [Cu3(La)4(Cl)6] complex, there are two crystallographically independent hexa- and penta-coordinated Cu(II) sites, where the thiazolidine ligand La units act as a monodentate ligand and a linker between the Cu(II) centers. The crystal packing of the [Cu3(La)4(Cl)6] complex is primarily affected by the weak non-covalent C-H∙∙∙Cl interactions. In accordance with Hirshfeld surface analysis, the Cl∙∙∙H, H∙∙∙H, S∙∙∙H, and N∙∙∙H percentages are 31.9%, 27.2%, 13.5%, and 9.9%, respectively. X-ray photoelectron spectroscopy confirmed the oxidation state of copper as Cu(II), as well as the presence of two different coordination environments around copper centers. The complex showed interesting antibacterial activity against the Gram-positive bacteria S. subtilis, with MIC = 9.7 µg/mL compared to MIC = 4.8 µg/mL for the control, gentamycin. Moreover, the Cu(II) complex showed an equal MIC (312.5 µg/mL) against C. albicans compared to ketoconazole. It also exhibits a very promising inhibitory activity against colon carcinoma (IC50 = 3.75 ± 0.43 µg/mL).

Sulphonamide motif is found extensively in numerous chemotherapeutic drug candidates, it acts by stopping the production of folate inside the bacterial cell. Current research has established the synthesis and characterization of new bioprecursor prodrugs of sulfadiazine. The first prodrug, 3, was synthesized via the coupling of diazonium salt of sulfadiazine with ethyl acetoacetate in AcONa at 0 °C. The second prodrug, sulfadiazine-pyrazole, 5, was furnished via cyclocondensation of the hydrazono derivative, 3, and 2-pyridyl hydrazine, 4. The generated data from the X-ray analysis is interpreted and refined to obtain the crystal structure of the target compound, 5. Density functional theory (DFT) method was used to calculate the optimized geometrical parameters, electronic state (HOMO–LUMO), and the electronic properties. Moreover, Hirshfeld analysis revealed that the most important contributions to the crystal packing of the prodrug 5 are H···H, O···H and H···C contacts.

In the present work, a novel heterocyclic hybrid of a spirooxindole system was synthesized via the attachment of ferrocene and triazole motifs into an azomethine ylide by [3 + 2] cycloaddition reaction protocol. The X-ray structure of the heterocyclic hybrid (1″R,2″S,3R)-2″-(1-(3-chloro-4-fluorophenyl)-5-methyl-1H-1,2,3-triazole-4-carbonyl)-5-methyl-1″-(ferrocin-2-yl)-1″,2″,5″,6″,7″,7a″-hexahydrospiro[indoline-3,3″-pyrrolizin]-2-one revealed very well the expected structure, by using different analytical tools (FTIR and NMR spectroscopy). It crystallized in the triclinic-crystal system and the P-1-space group. The unit cell parameters are a = 9.1442(2) Å, b = 12.0872(3) Å, c = 14.1223(4) Å, α = 102.1700(10)°, β = 97.4190(10)°, γ = 99.1600(10)°, and V = 1484.81(7) Å3. There are two molecules per unit cell and one formula unit per asymmetric unit. Hirshfeld analysis was used to study the molecular packing of the heterocyclic hybrid. H···H (50.8%), H···C (14.2%), Cl···H (8.9%), O···H (7.3%), and N···H (5.1%) are the most dominant intermolecular contacts in the crystal structure. O···H, N···H, H···C, F···H, F···C, and O···O are the only contacts that have the characteristic features of short and significant interactions. AIM study indicated predominant covalent characters for the Fe–C interactions. Also, the electron density (ρ(r)) at the bond critical point correlated inversely with the Fe–C distances.

Abstract This work deals with the synthesis and characterization of the novel 5-((5-chloro-1H-indol-2-yl)methylene)-1,3-diethyl-2-thioxodihydro-pyrimidine-4,6(1H,5H)-dione π-bridge (D–A–D) donor–acceptor–donor compound. Its exo-isomer structure has been proven by XRD-single-crystal analysis for the first time. The IR, UV–Vis., MS, CHN-, 1H and 13C NMR analysis were also carried out. The DFT-optimized structural-parameters were matched with the XRD-crystallographic data. The experimental-XRD-interactions in the lattice were compared to the computed Hirshfeld analysis (HSA), MEP map and Mulliken charge population. The DFT/6-311G(d) calculations like IR/B3LYP, TD-SCF, HOMO–LUMO, GRD and GIAO-NMR have been compared to their corresponding experimental parameters. Non-linear optical (NLO) crystal theoretical-analysis was carried out then compared to urea reference. The compound thermal activity was evaluated in an open-atmosphere by TG/DTG analysis.

The synthesis and crystal structures of three heteroleptic complexes of Zn(II) and Cd(II) with pyridine ligands (ethyl nicotinate (EtNic), N,N-diethylnicotinamide (DiEtNA), and 2-amino-5-picoline (2Ampic) are presented. The complex [Zn(EtNic)2Cl2] (1) showed a distorted tetrahedral coordination geometry with two EtNic ligand units and two chloride ions as monodentate ligands. Complexes [Zn(DiEtNA)(H2O)4(SO4)]·H2O (2) and [Cd(OAc)2(2Ampic)2] (3) had hexa-coordinated Zn(II) and Cd(II) centers. In the former, the Zn(II) was coordinated with three different monodentate ligands, which were DiEtNA, H2O, and SO42−. In 3, the Cd(II) ion was coordinated with two bidentate acetate ions and two monodentate 2Ampic ligand units. The supramolecular structures of the three complexes were elucidated using Hirshfeld analysis. In 1, the most important interactions that governed the molecular packing were O···H (15.5–15.6%), Cl···H (13.6–13.8%), Cl···C (6.3%), and C···H (10.3–10.6%) contacts. For complexes 2 and 3, the H···H, O···H, and C···H contacts dominated. Their percentages were 50.2%, 41.2%, and 7.1%, respectively, for 2 and 57.1%, 19.6%, and 15.2%, respectively, for 3. Only in complex 3, weak π-π stacking interactions between the stacked pyridines were found. The Zn(II) natural charges were calculated using the DFT method to be 0.8775, 1.0559, and 1.2193 for complexes 1–3, respectively. A predominant closed-shell character for the Zn–Cl, Zn–N, Zn–O, Cd–O, and Cd–N bonds was also concluded from an atoms in molecules (AIM) study.

The role of metalloenzymes in tumor progression had broadened their application in cancer therapy. Of these, MMPs and CAs are validated druggable targets that share some pivotal signaling pathways. The majority of MMPs or CAs inhibitors are designed as single-target agents. Despite their transient efficacy, these agents are often susceptible to resistance. This set the stage to introduce dual inhibitors of correlated MMPs and CAs. The next step is expected to target the common vital signaling nodes as well. In this regard, VEGFR-2 is central to various tumorigenesis events involving both families, especially MMP-2 and CA II. Herein, we report simultaneous inhibition of MMP-2, CA II, and VEGFR-2 via rationally designed hybrid 1,2,4-triazolo[4,3-a]pyrimidinone acyclo C-nucleosides. The promising derivatives were nanomolar inhibitors of VEGFR-2 (8; IC50 = 5.89 nM, 9; IC50 = 10.52 nM) and MMP-2 (8; IC50 = 17.44 nM, 9; IC50 = 30.93 nM) and submicromolar inhibitors of CA II (8; IC50 = 0.21 µM, 9; IC50 = 0.36 µM). Docking studies predicted their binding modes into the enzyme active sites and the structural determinants of activity regarding substitution and regioselectivity. MTT assay demonstrated that both compounds were 12 folds safer than doxorubicin with superior anticancer activities against three human cancers recording single-digit nanomolar IC50, thus echoing their enzymatic activities. Up to our knowledge, this study introduces the first in class triazolopyrimidinone acyclo C-nucleosides VEGFR-2/MMP-2/CA II inhibitors that deserve further investigation.

The reaction of PtCl2 with s-triazine-type ligand (HTriaz) (1:1) in acetone under heating afforded a new [Pt(Triaz)Cl] complex. Single-crystal X-ray diffraction analysis showed that the ligand (HTriaz) is an NNO tridentate chelate via two N-atoms from the s-triazine and hydrazone moieties and one oxygen from the deprotonated phenolic OH. The coordination environment of the Pt(II) is completed by one Cl−1 ion trans to the Pt-N(hydrazone). Hirshfeld surface analysis showed that the most dominant interactions are the H···H, H···C and O···H intermolecular contacts. These interactions contributed by 60.9, 11.2 and 8.3% from the whole fingerprint area, respectively. Other minor contributions from the Cl···H, C···N, N···H and C···C contacts were also detected. Among these interactions, the most significant contacts are the O···H, H···C and H···H interactions. The amounts of the electron transfer from the ligand groups to Pt(II) metal center were predicted using NBO calculations. Additionally, the electronic spectra were assigned based on the TD-DFT calculations.

A novel Ag(I) citrate complex with ethyl-3-quinolate (Et3qu) was synthesized. Its structure was confirmed using X-ray single crystal to be [Ag(Et3qu)2(citrate)]. It crystallized in the Triclinic crystal system and P-1 space group with unit cell parameters of a = 8.6475(2) Å, b = 11.4426(3) Å, c = 15.2256(3) Å, α = 73.636(2)°, β = 79.692(2)° and γ = 86.832(2)°, while the unit cell volume was 1422.19(6) Å3. In the unit cell, there are two [Ag(Et3qu)2(citrate)] molecules and one unit as the asymmetric formula. The molecular structure comprised one Ag(I) coordinated with two Et3qu molecules via two almost equidistant Ag-N bonds and one citrate ion acting as a mono-negative monodentate ligand via a short Ag-O bond (2.5401(14) Å). Hence, Ag(I) is tri-coordinated and has a highly distorted triangular planar coordination geometry which is more like to be described as a slightly distorted T-shape. The supramolecular structure of the [Ag(Et3qu)2(citrate)] complex was analyzed using Hirshfeld calculations. The H···H (39.3–40.1%), O···H (33.2-34.0%), C···C (9.1–9.5%) and C···H (7.2–7.4%) contacts shared significantly in the packing of the studied Ag(I) complex. The antimicrobial and anticancer activities of the Ag(I) complex were investigated. The [Ag(Et3qu)2(citrate)] complex has broad-spectrum antimicrobial activity specifically against the fungus A. fumigatus. In addition, the IC50 values of 1.87 ± 0.09 µg/mL and 0.95 ± 0.06 µg/mL against the breast MCF-7 and lung A-549 cell lines, respectively, revealed the potent anticancer activity of the [Ag(Et3qu)2(citrate)] complex compared to the free Et3qu (IC50 = 30.64 ± 1.98 and 22.89 ± 1.48 µg/mL, respectively).

Some new pyrimidine derivatives comprising arylsulfonylhydrazino, ethoxycarbonylhydrazino, thiocarbamoylhydrazino and substituted hydrazone and thiosemicarbazide functionalities were prepared from Biginelli-derived pyrimidine precursors. Heterocyclic ring systems such as pyrazole, pyrazolidinedione, thiazoline and thiazolidinone ring systems were also incorporated into the designed pyrimidine core. Furthermore, fused triazolopyrimidine and pyrimidotriazine ring systems were prepared. The synthesized compounds were evaluated for their calcium channel blocking activity as potential hypotensive agents. Compounds 2, 3a, 3b, 4, 11 and 13 showed the highest ex vivo calcium channel blocking activities compared with the reference drug nifedipine. Compounds 2 and 11 were selected for further biological evaluation. They revealed good hypotensive activities following intravenous administration in dogs. Furthermore, 2 and 11 displayed drug-like in silico ADME parameters. A ligand-based pharmacophore model was developed to provide adequate information about the binding mode of the newly synthesized active compounds 2, 3a, 3b, 4, 11 and 13. This may also serve as a reliable basis for designing new active pyrimidine-based calcium channel blockers.

The reaction of 4-hydroxyquinazoline (4HQZ) with aqueous solution of nitric acid afforded the corresponding quinazolinone-nitrate (4HQZN) complex in very good yield. The crystal structure of 4HQZN was determined and its structural and supramolecular structural aspects were analyzed. 4HQZN crystallized in the space group P21/c and monoclinic crystal system with one [4HQZ-H]+[NO3]− formula and Z = 4. Its supramolecular structure could be described as a 2D infinite layers in which the 4HQZN molecules are connected via N-H…O and C-H…O hydrogen bridges. Using DFT calculations, the relative stability of five suggested isomers of 4HQZN were predicted. It was found that the medium effects have strong impact not only on the isomers’ stability but also on the structure of the 4HQZN. It was found that the structure of 4HQZN in DMSO and methanol matched well with the reported X-ray structure which shed the light on the importance of the intermolecular interactions on the isomers’ stability. The structure of 4HQZN could be described as a proton transfer complex in which the nitrate anion acting as an e-donor whiles the protonated 4HQZ is an e-acceptor. In contrast, the structure of the isolated 4HQZN in gas phase and in cyclohexane could be described as a 4HQZ…HNO3 hydrogen bonded complex. Biological screening of the antioxidant, anticancer and antimicrobial activities of 4HQZ and 4HQZN was presented and compared. It was found that, 4HQZN has higher antioxidant activity (IC50 = 36.59 ± 1.23 µg/mL) than 4HQZ. Both of 4HQZ and 4HQZN showed cell growth inhibition against breast (MCF-7) and lung (A-549) carcinoma cell lines with different extents. The 4HQZ has better activity with IC50 of 178.08 ± 6.24 µg/mL and 119.84 ± 4.98 µg/mL, respectively. The corresponding values for 4HQZN are 249.87 ± 9.71 µg/mL and 237.02 ± 8.64 µg/mL, respectively. Also, the antibacterial and antifungal activities of 4HQZN are higher than 4HQZ against all studied microbes. The most promising result is for 4HQZN against A. fumigatus (MIC = 312.5 μg/mL).

Herein, we report a facile synthesis of ethyl-2-(4-aminophenoxy)acetate 4 as a building synthon for novel dual hypoglycemic agents. This building template was synthesized by alkylation of 4-nitrophenol with ethyl bromo-acetate followed by selective reduction of the nitro group. This reduction methoddoes not require nascent hydrogen or any reaction complexity; it goes easily via consecutive reaction in NH4Cl/Fe to yield our target synthon as very pure crystals. This product was characterized by 1HNMR, 13CNMR, COSY, NOESY NMR spectroscopy, and elemental analysis. Additionally, its structure was studied and approved by X-ray single crystal structure determination. The unit cell parameters are a = 8.2104(6)Å, b = 10.3625(9)Å, c = 11.9562(9)Å, α = 101.787(7), β = 91.849(6), and γ = 102.755(7)°, indicating that 4 was crystallized in the triclinic crystal system. The cooperative non-covalent interactions are also discussed with the aid of Hirshfeld surface analysis. The H…H, H…C, and O…H interactions have a major contribution in the molecular packing of 4. Moreover, different quantum chemical parameters were computed and discussed based on DFT calculations. The experimental UV/Vis spectra showed two bands at 299 and 234 nm, which were calculated using the TD-DFT method at 286 (f = 0.068) and 226 nm (f = 0.294), respectively. These bands were assigned to HOMO→LUMO (95%) and HOMO→LUMO+2 (86%) transitions, respectively.

Hydrolysis/[3 + 2] cycloaddition/elimination cascades employed for the synthesis of unexpected tricyclic compound derived from isoquinoline. Reaction of ethylene derivative 1 with the isoquinoline ester iminium ion 2 in alkaline medium (MeOH/NEt3) under reflux for 1 h resulted in the formation of the fused pyrrolo[2,1-a]isoquinoline derivative 3. Its structure was elucidated by X-ray single crystal and other spectrophotometric tools. Hirshfeld calculations for 3 and its crystal structure analysis revealed the importance of the short O…H (19.1%) contacts and the relatively long H…C (17.1%), Cl…H (10.6%) and C…C (6.1%) interactions in the molecular packing. DFT calculations were used to compute the electronic and spectroscopic properties of the studied system. The studied compound has polar nature (3.5953 Debye). TD-DFT calculations assigned the shortest wavelength band (220 nm) to the HOMO−1→LUMO+2 (57%), HOMO−1→LUMO+4 (14%) mixed excitations. The calculated NMR chemical shifts correlated very well with the experimental data (R2 = 0.93–0.94).

A new spirooxindole hybrid engrafted imidazo[2,1-b]thiazole core structure was designed and achieved via [3+2] cycloaddition reaction approach. One multi-component reaction between the ethylene derivative based imidazo[2,1-b]thiazole scaffold with 6-Cl-isatin and the secondary amine under heat conditions afforded the desired compound in a stereoselective manner. The relative absolute configuration was assigned based on single-crystal X-ray diffraction analysis. Hirshfeld calculations for 4 revealed the importance of the H…H (36.8%), H…C (22.9%), Cl…H (10.4%) and S…H (6.6%), as well as the O…H (4.7%), N…H (5.3%), Cl…C (1.6%), Cl…O (1.0%) and N…O (0.5%) contacts in the crystal stability. DFT calculations showed excellent straight-line correlations (R2 = 0.9776–0.9962) between the calculated and experimental geometric parameters. The compound has polar nature (3.1664 Debye). TD-DFT and GIAO calculations were used to assign and correlate the experimental UV-Vis and NMR spectra, respectively.

In this paper, synthesis, single-crystal X-ray structure, Hirshfeld and DFT studies of 1,8-dichloro-9,10-dihydro-9,10-ethanoanthracene-11-carboxylic acid are discussed. Different intermolecular contacts affecting the crystal stability are studied using Hirshfeld calculations. The H…Cl and O…H contacts are the most significant, showing corresponding interaction distances of 2.731 Å (Cl2…H10) and 1.681Å (H1…O1), 2.328 Å (O1…H13), 2.510 Å (O1…H12) based on Hirshfeld calculations. DFT calculations are carried out to study the electronic behavior, as well as the 1H- and 13C-NMR spectra of the synthesized compound. The computed NMR chemical shifts show excellent correlation with the experimental data (R2 = 0.9884–0.9705).

A series of new oxindole-based spiro-heterocycles bearing the benzo[b]thiophene motif were synthesized via a 1,3-dipolar cycloaddition reaction and their acetylcholinesterase (AChE) inhibitory activity was evaluated. All the synthesized compounds exhibited moderate inhibitory activities against AChE, while IIc was found to be the most active analog with an IC50 value of 20,840 µM·L−1. Its molecular structure was a 5-chloro-substituted oxindole bearing benzo[b]thiophene and octahydroindole moieties. Based on molecular docking studies, IIc was strongly bound to the catalytic and peripheral anionic sites of the protein through hydrophilic, hydrophobic, and π-stacking interactions with Asp74, Trp86, Tyr124, Ser125, Glu202, Ser203, Trp236, Trp286, Phe297, Tyr337, and Tyr341. These interactions also indicated that the multiplicity of the IIc aromatic core significantly favored its activity.

Inhibition of α-amylase and α-glucosidase by specified synthetic compounds during the digestion of starch helps control post-prandial hyperglycemia and could represent a potential therapy for type II diabetes mellitus. A new series of spiroheterocyclic compounds bearing oxindole/benzofuran/pyrrolidine/thiazolidine motifs were synthesized via a 1,3-dipolar cyclo-addition reaction approach. The specific compounds were obtained by reactions of chalcones having a benzo[b]furan scaffold (compounds 2a−f), with a substituted isatin (compounds 3a−c) and heterocyclic amino acids (compounds 4a,b). The target spiroindolone analogues 5a−r were evaluated for their potential inhibitory activities against the enzymes α-amylase and α-glucosidase. Preliminary results indicated that some of the target compounds exhibit promising α-amylase and α-glucosidase inhibitory activity. Among the tested spiroindolone analogues, the cycloadduct 5r was found to be the most active (IC50 = 22.61 ± 0.54 μM and 14.05 ± 1.03 μM) as α-amylase and α-glucosidase inhibitors, with selectivity indexes of 0.62 and 1.60, respectively. Docking studies were carried out to confirm the binding interaction between the enzyme active site and the spiroindolone analogues.