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Naturally available halloysite nanotubes (HNTs) and HNTs/Kaolin mixtures obtained from different locations in South Australia were processed and purified to varying degrees by crushing, blunging and reblunging, sedimentation followed by filtration. The microscopic and adsorption results revealed that the samples are highly porous in nature and exhibited tubular morphology with a high specific surface area. It was found that the halloysite content in the samples obtained from different locations was quite different although the processing steps make a slight difference in the final halloysite content in the samples. Out of the several materials characterized, HNT1, halloysite from Camel Lake, has a higher quantity of halloysite content (88%) and exhibits a specific surface area of ca. 50.8 m2/g. It was found that the halloysite nanotube HNT1 exhibited a CO2 adsorption capacity of 3.4 mmol/g at 25 °C, which increased to 6.1 mmol/g at 0 °C. Interestingly, CO2 adsorption per unit surface area of the studied HNT1 was estimated to be 120 μmol/m2 which is relatively higher than that of the existing halloysites and other well-known commercial materials such as activated carbon, mesoporous silica and carbon nitride materials. The higher adsorption capacity of HNT is mainly attributed to the excellent surface and tubular morphology with small pores and free hydroxyl groups present at the inner and outside surface of HNT, which play a significant role in the CO2 adsorption process.

Anticancer therapeutics with profiles of high potency, low toxicity, and low resistance is of considerable interest. A new series of functionalized spirooxindole linked with 3-acylindole scaffold is reported, starting from chalcones derived from 3-acetyl indole with isatin, and l-4-thiazolidinecarboxylic acid. The reactions proceeded regioselectivity, stereoselectivity, without side products in high yield (71–89%). The new spirooxindole hybrids have been evaluated in vitro for their antiproliferative effects against colon cancer (HCT-116), hepatocellular carcinoma (HepG2) and prostate cancer (PC-3). The selectivity of their activity was evaluated. Some of the synthesized compounds showed considerable anticancer activities. Compound 4k proved to retain a high cytotoxic activity and selectivity against colon cancer cells HCT-116 (IC50 = 7 ± 0.27 µM, SI: 3.7), and HepG2 (IC50 = 5.5 ± 0.2 µM, SI: 4.7) in comparison to (IC50 = 12.6 ± 0.5, SI: 0.4 and 5.5 ± 0.3 µM, SI: 0.9, respectively). Compound 4k was less active (IC50 = 6 ± 0.3 µM, SI: 4.3) than cisplatin (IC50 = 5 ± 0.56 µM, SI: 1.0) but showed greater selectivity towards prostate cancer cells PC-3 in comparison to cisplatin. The details of the binding mode of the active compounds were clarified by molecular docking. Ligand Efficiency (LE) and Ligand Lipophilic Efficiency (LLE) were evaluated and revealed that compound 4k had acceptable value.

A green, simple and efficient protocol for the synthesis of the two new barbituric acid derivatives; 4 and 5 is described. One pot fashion of 2 mol of barbituric acid derivatives with 3-fluorobenzaldehyde in green solvent (H2O) providing compound 4. Reaction of equimolar of barbituric acid derivatives, dimedone and 4-(trifluoromethyl)benzaldehyde gave compound 5. Using the density functional theory at the B3LYP level and 6-311G(d,p) as basis set, the molecular structures of the studied compounds were optimized. The minimum energy structures have geometrical parameters correlated well with the experimental data. 4 has two barbituric acid moieties more deviated from the planarity than the barbiturate ring in 5. The latter exists in the enol form and it is stabilized by strong intramolecular hydrogen bonding interactions. The NBO analysis revealed the presence of significant π-π* intramolecular charge transfer in this ring, while this effect is absent in 4. The electronic spectra of the studied compounds were investigated experimentally and theoretically using the TD-DFT method. The compound which has one more conjugated ring (5) has one more band at longer wavelength of 318 nm (calc. 313.5 nm) which is assigned to H→L (93%) excitation. The anti-oxidant activity as reactive oxygen scavenger was examined in this research. The NO and DPPH radical scavenger assays were carried out. The results clearly demonstrated that compounds 4 and 5 possess a significant effect as reactive oxygen scavenger compared with the standard drugs. The ligand efficiency (LE) metrics as LE value and ligand lipophilic efficiency (LLE) were calculated and they showed that compound 4 has better character as drug likeness candidate rather than compound 5. The docking study of the compounds showed that compound 4 docked with the receptor (PDB ID: 3JSW) through lipophilic-lipophilic interaction. Interestingly, compound 5 represent dissimilarity from compound 4.

Herein we reported the utility of one-pot multicomponent based [3+2] cycloaddition reaction transformation to prepare a new two hybrids of spirooxindoles engrafted with pyrazole skeleton. Upon treatment of the electron-deficient olefins based pyrazole motif with in situ the generated azomethine ylides (AY) of sarcosine with the 6-chloro-isatin afforded spiroadducts. To enlighten the regio- and diastereo-selectivity of these spiroheterocycles, single crystal X-ray diffraction analysis was presented. Using Hirshfeld calculations, many short distance contacts such as O…H, Cl…H, N…H, H…C, C…C and Cl…S have a great impact on the molecular packing and the crystal stability of 8a and 8b. The latter showed some Cl…Cl inter halogen interactions (Cl1…Cl3; 3.358 A). In addition, DFT calculations were used to compute the electronic properties as well as the 1H- and 13C-NMR spectra of the studied systems. Both compounds are polar where 8b (3.995 Debye) has higher dipole moment than 8a (3.414 Debye). The NMR chemical shifts were calculated and found in excellent correlations between the calculated and experimental data were obtained (R2 = 0.94–0.98).

Indole containing compounds have acquired conspicuous significance due to their wide spectrum of biological activities. Synthesis of a series of enantiomerically pure indole derivatives 3a-r via Friedel–Crafts alkylation of indole 1 with enones 2a-r were described here. The products were isolated in a moderate to excellent yields (upto 89%) with excellent enantioselectivities (upto 99.9% ee). These compounds 3a-r were evaluated for their in vitro α-glucosidase inhibitory activity and some of them were identified as potent inhibitors (IC50 = 4.3 ± 0.13–43.9 ± 0.51 μM) with several fold higher activity than the clinically used α-glucosidase inhibitor, acarbose (IC50 = 840 ± 1.73 μM). To the best of knowledge, this is the first report of the propanone substituted indole ring containing compounds by in vitro α-glucosidase enzyme inhibition.

In this work, polycyclic heterocycles containing spirooxindole, pyrrolidine, and thioxothiazolidin-4-one rings have been synthesized via the regioselective 1,3-dipolar cycloaddition of azomethine ylide, which is generated in situ by the condensation of the dicarbonyl compound isatin and the secondary amino acid ( l -proline), with 5-arylidine-2-thioxothiazolidin-4-one as the dipolarophile. The structure of the synthesized compounds 4a and 4b were determined by using X-ray single crystal diffraction, and also, Hirshfeld surface analysis were reported. Their geometric parameters were calculated using density functional theory at the B3LYP/6-311G (d,p) level of theory. Both compounds showed antimicrobial and antifungal activity better than selected standards (ampicillin and gentamicin in case of antibacterial activity and Amphotericin A and fluconazole in case of antifungal activity). Molecular docking study of the synthesized compounds indicated that phenyl group plays an important role in determination of compound interaction inside the receptors.

Barbiturate derivatives are privileged structures with a broad range of pharmaceutical applications. We prepared a series of 5-monoalkylated barbiturate derivatives (3a–l) and evaluated, in vitro, their antioxidant (DPPH assay), and α-glucosidase inhibitory activities. Compounds 3a–l were synthesized via Michael addition. The structure of compound 3k was determined using X-ray single-crystal diffraction, and geometric parameters were calculated using density functional theory at the B3LYP/6-311G(d,p) level of theory. Further, the structural analysis of 3k were also investigated. Biological studies revealed that compounds 3b (IC50 = 133.1 ± 3.2 μM), 3d (IC50 = 305 ± 7.7 μM), and 3e (IC50 = 184 ± 2.3 μM) have potent α-glucosidase enzyme inhibitors and showed greater activity than the standard drug acarbose (IC50 = 841 ± 1.73 μM). Compounds 3a–3i were found to show weak antioxidant activity against 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals (IC50 = 91 ± 0.75 to 122 ± 1.0 μM) when tested against a standard antioxidant, gallic acid (IC50 = 23 ± 0.43 μM).

Two new malonamide derivatives were synthesized via the Michael addition of N1,N3-di(pyridin-2-yl)malonamide to α,β-unsaturated ketones using a 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) catalyst at room temperature. All reactions efficiently furnished the desired malonamide derivatives, which differed only in their substitution on one phenyl group, with one derivative bearing a bromine substituent and the other bearing a methyl group. The structures of newly synthesized compounds were then elucidated by single-crystal X-ray diffraction, infrared spectroscopy, NMR spectroscopy, mass spectrometry, and elemental analysis. In addition, the synthesized compounds were evaluated for their in vitro cytotoxicity against cancer cell lines and for α-glucosidase inhibition. The target compounds exhibited enhanced α-glucosidase inhibition activity (i.e., IC50 = 12.8 ± 0.1 and 28.4 ± 0.2 μM) compared to the common drug acarbose (IC50 = 840 ± 1.73 μM). Both compounds were found to be non-cytotoxic against H460 (lung carcinoma) and T3T (normal fibroblast) cell lines. In addition, the bromo-substituted derivative exhibited weak cytotoxic against cervical cancer HeLa (IC50 = 13.8 ± 0.4 μM) and breast cancer MCF-7 (IC50 = 21.11 ± 0.88 μM) cell lines, while the methyl-substituted derivative showed weak cytotoxicity against the MCF-7 cell line (IC50 = 47.9 ± 0.7 μM). Density functional theory (DFT) B3LYP/6-311G(d,p) calculations were employed to examine the molecular structures and electronic properties of the prepared compounds. As expected, the bromo-derivative (2.2377 D) exhibited a higher polarity than the methyl-derivative (1.9160 D). Furthermore, the HOMO and LUMO diagrams were constructed and the electronic spectra of both compounds were assigned using time-dependent (TD)-DFT calculations. Finally, the calculated NMR chemical shifts correlated well with the experimental data.

The one-pot synthesis reaction of barbituric acid derivative, 1,3-cyclohexandione, and 4-fluorobenzaldehyde in water mediated by NHEt2 as base afforded 4 with excellent yield. The synthesized compound was characterized by spectrophotometric tools as well as X-ray single crystal diffraction technique. The stability of the nine possible isomers of the synthesized compound was studied using the B3LYP method and 6-31G(d,p) basis set. The electronic and spectroscopic properties of the most stable isomer were predicted. The UV–Vis absorption spectrum displayed two bands at 203 and 257 nm in the solvent chloroform. The latter was calculated at 235.6 nm (f = 0.1995) in the gas phase due to H-2→L (42%) and H-1→L+2 (14%) excitations. In solution, using chloroform as a solvent, a slight bathochromic shift to 237.6 nm with an increase in the absorption intensity (f = 0.2898) was predicted. The molecular orbital energy level diagram of this transition band was characterized mainly by π-π* transitions. The 13C and 1H NMR chemical shifts correlated well with the experimental data. The correlations had higher correlation coefficients (R2) when solvent effects were considered. The atomic charges were calculated using natural population analysis and the charged regions were presented using a molecular electrostatic potential (MEP) map. The synthesized compound was examined as a hypoglycemic agent via inhibition of α-glucosidase and β-glucuronidase enzymes. Its inhibitory activity against α-glucosidase was 10 times greater than the inhibitory activity of the standard drug acarbose (IC50 77.9 ± 0.3 μM and 840 ± 1.73 μM, respectively). Moreover, the target compound was evaluated for anticancer activity against MCF-7, H460, 3T3, and Hela cell lines. It demonstrated inhibitory activity against the MCF-7 and H460 cell lines with IC50 5.80 ± 0.12 and 19.6 ± 0.5 μM, respectively, in comparison to doxorubicin. The docking study was performed using the OpenEye program.

Diethylamine catalyzed tandem Knoevenagel–Michael reactions have been carried out in aqueous medium as an efficient, greener and cost effective process for the simple one-pot synthesis of bis-dimedone derivatives. Reaction of substituted aromatic aldehyde (1 equiv.) and dimedone (2 equiv.), in the presence of aqueous diethylamine medium at room temperature provides bis-dimedone derivatives 3a–n in excellent yields (87–95%) within a very short reaction time (15–60 min). All the bis-dimedone derivatives were obtained in high purity and the products were fully characterized by physical and spectroscopic data. The structures of compounds 3b,c were elucidated by single crystal X-ray diffraction technique. Compound 3b crystallizes in the monoclinic space group P 21/n with a = 10.2895(9) A , b = 18.0995(15) A , c = 15.8615(13) A , α = 90°, β = 107.975(2)°, γ = 90°, V = 2809.8(4) A 3 , and Z = 4. Compound 3c crystallizes in the monoclinic space group P 21/n with a = 10.2816(16) A , b = 18.080(3) A , c = 15.637(2) A , α = 90°, β = 107.076(4)°, γ = 90°, V = 2778.6(7) A 3, and Z = 4. The use of inexpensive, eco-friendly and readily available reagents, easy work-up, and high purity products makes the procedure a convenient and robust method for the synthesis of tandem Knoevenagel–Michael adducts.

A new unexpected hybrid based on the arylidene-thiazolidinone and 1,3,4-thiadiazole scaffolds via combined S-alkylation and Smiles rearrangement dual protocols. The one-pot reaction of arylidene-thiazolidinone with the hydrazonoyl chloride in a basic medium (Et3N) with benzene as solvent afforded the discovered compound at room temperature (25 °C). The molecular architecture of the designed hybrid were assigned based on the spectrophotometric tools. Based on Hirshfeld analysis, the molecules are connected by short O…H (19.6%), S…H (7.3%), H…C (20.1%), and C…C (0.7%) interactions. Density-functional theory (DFT) calculations indicated polar molecules (7.595 Debye). Its structure is stabilized by different σ-σ*, π→π*, n→σ*, and n→π* intramolecular charge transfer (IMCT) processes. The two longest wavelength bands observed in the UV–Vis spectra of diethyl(S,Z)-2-(2-(5-(4-hydroxybenzylidene)-4-oxo-4,5-dihydrothiazol-2-yl)-2-phenylhydrazinyl)-3-phenyl-2,3-dihydro-1,3,4-thiadiazole-2,5-dicarboxylate 3 were calculated at 364.0 (HOMO→LUMO+1) and 305.1 nm (HOMO-2→LUMO), which considerably agree with the experimental data.

The nitrogen containing spiro-heterocycle is one of the privileged synthetic motif that constitutes various naturally occurring molecules and displays a broad range of pharmaceutical and biological activities. A new methodology was developed for the synthesis of 2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraones spiro-heterocyclic derivatives via cascade cyclization of [5+1] double Michael addition reaction of N,N-dimethylbarbituric acid with the derivatives of diaryldivinylketones in the presence of diethylamine at ambient temperature. The developed protocol is highly capable of furnishing diazaspiro[5.5]undecane derivatives 3a–m in excellent yields (up to 98%), from easily accessible symmetric and non-symmetric divinylketones 2a–m, containing aryl and heteroaryl substituents. The diazaspiro-heterocyclic structure was mainly elucidated by NMR and X-ray crystallographic techniques. The single-crystal X-ray studies revealed that, the cyclohexanone unit of spirocycles often prefers a chair conformation rather than twisted conformation. The intermolecular hydrogen bonding and CArH⋯π, π–π stacking interactions driving forces are mainly responsible for the crystal packing.

A new Pd(II) complex, [Pd(Triaz)Cl], with the hydrazono-s-triazine ligand, 2,4-di-tert-butyl-6-((2-(4-morpholino-6-(phenylamino)-1,3,5-triazin-2-yl)hydrazono)methyl)phenol (HTriaz), was synthesized by the reaction of PdCl2 with the organic ligand (1:1) in acetone under isothermal conditions. The molecular structure of the [Pd(Triaz)Cl] complex was determined using FTIR and 1H NMR spectroscopic techniques, and single-crystal X-ray diffraction. Moreover, using Hirshfeld surface analysis, the percentages of the intermolecular interactions were determined. The obtained values were 60.6%, 11.6%, 8.1%, 3.6%, and 5.0% for the H⋯H, C⋯H, O⋯H, N⋯H, and Cl⋯H interactions, respectively. Among them, the O⋯H, C⋯H and C⋯N interactions are considered extremely important. Natural bond orbital calculations have been used to calculate the amount of electron transfer from the ligand to the metal ion and to evaluate the Pd–N, Pd–O, and Pd–Cl coordination bonding interactions.

The discovery of metal-based complexes as potent urease inhibitor is a challenge. In this work, the new [CoL2]NO3 complex of the barbituric acid based ligand, 5-((benzylamino)methylene)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione (HL) was synthesized. The structural features of the synthesized Co(III) complex were assigned using the single crystal X-ray diffraction techniques, Hirshfeld analysis, DFT calculations and other physicochemical techniques. Its structure comprised CoN4O2 coordination sphere with two ligands units (L¯) as mononegative tridentate NNO-donor ligand. The potency as urease inhibitor was evaluated in vitro. The [CoL2]NO3 complex (IC50 = 16.0 ± 0.54 µM) is better inhibitor than the drug acetohydroxamic acid as a reference (IC50 = 20.3 ± 0.43 µM). The docking studies of the [CoL2]NO3 was carried out using the active center of Jack Bean Urease (PDB 4GY7), and the resulting poses were analyzed visually to understand the interaction pattern.

Considerable attention has been focused on the [1,3] dipolar cycloaddition reaction approach of olefin with amino acid (sarcosine), and isatin which underwent smoothly, and afforded a highly functionalized complex molecule. The target spiroindolone analogue 4 was synthesized in excellent yield. The desired compound was elucidated based on X-ray single crystal diffraction technique. Compound 4 was examined against three different cancer cell lines for liver, breast and colorectal cancer (HepG2, MCF-7 and HCT-116, respectively). It showed high selectivity against colon cancer (HCT-116). Hirshfeld molecular packing analysis of 4 showed that the H⋯H, Cl⋯H and C⋯H contacts are the most abundant while the N⋯H and O⋯H hydrogen bonding interactions are the strongest. Molecular and electronic structures as well as the Uv–Vis and NMR spectra of 4 were discussed based on DFT calculations. The longest wavelength band observed at 298 nm was assigned for the HOMO-2/HOMO-1→LUMO excitations. The 1H and 13C NMR chemical shifts of 4 were calculated and compared with the experimental data (0.934–0.954).

Ferrocene-based anti-inflammatory drug discovery has become an important area in medicinal chemistry. Utilizing the condensation of isatin or ferrocene carbaldehyde with nucleophile, such as oxamic acid hydrazide, the desired isatin 1, and ferrocene 2 oxamohydrazide derivatives were smoothly synthesized in high purity and yield. The structures of the isatin, and ferrocene oxamohydrazides were elucidated using single crystal X-ray diffraction technique, and DFT calculations. Hirshfeld analysis sheds the light on the importance of the O⋯H hydrogen bonds in the molecular packing in both compounds. The oxamohydrazides were examined for anti-inflammatory, and anti-leishmanial activities. The ferrocene oxamohydrazide analogue 2, (IC50 = 5.7 ± 0.3 μM) exhibited a potent anti-inflammatory effect, and was two times more active than the tested ibuprofen as control (IC50 = 11.2 ± 1.9 μM).

A simple and straightforward route to 5-monoalkylbarbiturates by the NHEt2 catalyzed Michael reaction of 1,3-dimethylbarbituric acid and α,β-unsaturated ketones is described. Significantly, the reaction exclusively furnished 5-monoalkylbarbiturates. Under neat conditions, the mixing and grinding of a representative 1,5-diketone and hydroxylamine hydrochloride gave the corresponding 1,2-oxazepine in very good yield.

Synthesis of (±)-1,3-dimethyl-5-(1-(3-nitrophenyl)-3-oxo-3-phenylpropyl)pyrimidine-2,4,6(1H,3H,5H)-trione (3) is reported. The structure of compound 3 was deduced by using spectroscopic methods, X-ray crystallography, and DFT calculations. The calculated geometric parameters were found to be in good agreement with the experimental data obtained from the X-ray structure. The NBO calculations were performed to predict the natural atomic charges at the different atomic sites and to study the different intramolecular charge transfer (ICT) interactions. The high LP(3)O6 →z BD*(2)O5–N3 ICT interaction energy (165.36 kcal/mol) indicated very strong n → π* electron delocalization while the small LP(2)O → BD*(1)C–H ICT interaction energies indicated that the C–H … O intramolecular interactions are weak. The 1H and 13C NMR chemical shifts calculated using GIAO method showed good agreement with the experimental data. The calculated electronic spectra of the studied compound using TD-DFT method showed intense electronic transition band at 243.9 nm (f = 0.2319) and a shoulder at 260.2 nm (f = 0.1483) which were due to H-4/H-2/H-1/H → L+2 and H-5 → L electronic excitations, respectively. Compound 3 (IC50 = 305 ± 3.8 μM) was identified as a potent inhibitor of α-glucosidase in vitro and showed several fold more inhibition than the standard drug acarbose (IC50 = 841 ± 1.73 μM). Molecular docking of the synthesized compound was discussed.

We describe here the synthesis of dihydropyrimidines derivatives 3a-p, and evaluation of their α-glucosidase enzyme inhibition activities. Compounds 3b (IC50=62.4±1.5 μM), 3c (IC50=25.3±1.26 μM), 3d (IC50=12.4±0.15 μM), 3e (IC50=22.9±0.25 μM), 3g (IC50=23.8±0.17 μM), 3h (IC50=163.3±5.1 μM), 3i (IC50=30.6±0.6 μM), 3m (IC50=26.4±0.34 μM), and 3o (IC50=136.1±6.63 μM) were found to be potent α-glucosidase inhibitors in comparison to the standard drug acarbose (IC50=840±1.73 μM). The compounds were also evaluated for their in vitro cytotoxic activity against PC-3, HeLa, and MCF-3 cancer cell lines, and 3T3 mouse fibroblast cell line. All compounds were found to be non cytotoxic, except compounds 3f and 3m (IC50=17.79±0.66-20.44±0.30 μM), which showed a weak cytotoxic activity against the HeLa, and 3T3 cell lines. In molecular docking simulation study, all the compounds were docked into the active site of the predicted homology model of α-glucosidase enzyme. From the docking result, it was observed that most of the synthesized compounds showed interaction through carbonyl oxygen atom and polar phenyl ring with active site residues of the enzyme.

A simple, economical, and green approach to the synthesis of 5,5′-((2,4-dichlorophenyl)methylene) bis (1,3-dimethylpyrimidine-2,4,6(1 H ,3 H ,5 H )-trione) 4 using a tandem Aldol condensation-Michael addition process in aqueous diethylamine medium was described. The 3D structure of the latter was confirmed by single-crystal X-ray structure determination. The molecular structure of the titled compound was calculated using DFT B3LYP/6-311G(d,p) method. The calculated geometric parameters are in good agreement with the experimental data obtained from our reported X-ay structure. The two pyrimidinetrione rings have C16 and C20 atoms deviated significantly from the ring plane. The electronic spectra of the studied compound have been calculated using the TD-DFT method. The longest wavelength band (257.8 nm, f = 0.0276) occurs due to H → L (86%) transition. The 1 H and 13 C NMR calculated chemical shifts using GIAO method showed good correlation with the experimental data. The molecular electrostatic potential (MEP) showed that the most reactive sites for electrophilic and nucleophilic attacks are the carbonyl oxygen (O5) and the H21 atoms, respectively. The NBO calculations were performed to predict the natural atomic charges at the different atomic sites and to study the different intramolecular charge transfer (ICT) interactions occurring in the studied system. Interestingly, there is some delocalization of electron densities from the occupied σ-type NBO of the C20 H21 to the unoccupied π ∗ -NBO of the two adjacent carbonyl groups.

A variety of 2-thioxothiazolidin-4-one derivatives were prepared and their in vitro antimicrobial activities were studied. Most of these compounds showed significant antibacterial activity specifically against Gram-positive bacteria, among which compounds 4a,e,g, 5b,e,g,h and 6f exhibit high levels of antimicrobial activity against Bacillus subtilis ATCC 10400 with Minimum Inhibitory Concentration (MIC) value of 16 lg/mL. All compounds have antifungal activity against Candida albicans. Unfortunately, however, none of the compounds were active against Gram-negative bacteria. The chemical structure of 3 was confirmed by X-ray single crystal diffraction technique. DFT calculations of 3 have been performed on the free C10H7Cl2NO2S2, 3a and the H-bonded complex, C10H7Cl2NO2S2H2O, 3b to explore the effect of the H-bonding interactions on the geometric and electronic properties of the studied systems. A small increase in bond length was observed in the C12–O6 due to the H-bonding interactions between 3a and water molecule. MEP study has been used to recognize the most reactive sites towards electrophilic and nucleophilic attacks as well as the possible sites for the H-bonding interactions. The TD-DFT calculations have been used to predict theoretically the electronic spectra of the studied compound. The most intense transition band is predicted at 283.9 nm due to the HOMO-2/HOMO-1 to LUMO

A variety of zwitterionic adducts were synthesized by using means green chemistry method. The products contain the biologically active barbituric acid moiety embedded in zwitterion products. Both features are pharmaceutically relevant. The chemical structures were deduced by 1H-, 13C-, NMR and HRMS spectral analysis, and X-ray diffraction techniques. In vitro evaluation for the antioxidant activities were carried out towards the inhibition of nitric oxide (NO) radical, known to regulate a mechanism of signals for various cellular functions. NO also play an important role as a mediator of various pathological conditions responsible for cellular damages such as strokes, cancers, diabetes, chronic heart failure and inflammatory disease and various neurodegenerative disorders. All tested compounds were found to be more potent nitric oxide scavengers as compared to standard drug ascorbic acid (IC50 = 618 ± 2.0 μM). Compounds 4c and e exhibiting several hundred fold more activity against nitric oxide radical with IC50 values of 69 ± 1.66 and 70.1 ± 0.89 μM respectively, as compared to standard drug ascorbic acid (IC50 = 618 ± 2.0 μM).

Four chalcone structures based on cyclohexanone cores were presented. The structures of bis-benzylidenecyclohexanone analogs 3a-d were elucidated using spectrophotometric and single-crystal X-ray techniques. Compounds 3a, 3b, and 3d crystalized in the monoclinic crystal system with the space group P21/c. However, 3c crystalized in the orthorhombic system with the space group Pna21. A set of computational studies related to the structures were carried out. Using the B3LYP method and the 6-31G(d,p) basis set, the molecular structures of the studied dienones were optimized, followed by the evaluation of their electronic properties and UV–vis spectra. The bond distances and angles well-correlated with the experimental data. All the dienones were stabilized by C–H⋯O intramolecular H-bonding interactions. The presence of two Cl atoms at the ortho-position of each phenyl ring in 3c caused steric hinderance with the cyclohexanone ring, leading to the weakest H⋯O interactions among the studied compounds. The TD-DFT method was used to assign and explain the origin of the electronic spectra of the studied dienones.