Heck reaction synthesis of anthracene and naphthalene derivatives as traps and clean chemical sources of singlet molecular oxygen in biological systems.

Studies have previously shown that anthracene and naphthalene derivatives serve as compounds for trapping and chemically generating singlet molecular oxygen [O2(1Δg)], respectively. Simple and efficient synthetic routes to anthracene and naphthalene derivatives are needed, for improved capture and release of O2(1Δg) in cellular environments. Because of this need, we have synthesized a dihydroxypropyl amide naphthlene endoperoxide as a O2(1Δg) donor, as well as five anthracene derivatives as O2(1Δg) acceptor. The anthracene derivatives bear dihydroxypropyl amide, ester, and sulfonate ion end groups connected to 9,10-positions by way of unsaturated (vinyl) and saturated (ethyl) bridging groups. Heck reactions were found to yield these six compounds in easy-to-carry out 3-step reactions in yields of 50-76%. Preliminary results point to the potential of the anthracene compounds to serve as O2(1Δg) acceptors and would be amenable for future use in biological systems to expand the understanding of O2(1Δg) in biochemistry.

Using the Supermolecule Approach To Predict the Nonlinear Optics Potential of a Novel Asymmetric Azine.

Organic molecules with electron acceptors or withdrawal substituents terminal at π-conjugated system are promising candidates to be explored as materials with high linear and nonlinear optical properties. On the basis of these features, a novel asymmetric azine ( 7E, 8E)-2-(3-methoxy-4-hydroxy-benzylidene)-1-(4-nitrobenzylidene)hydrazineC15H13N3O4 (NMZ) was synthesized. The molecular structure of NMZ was elucidated by X-ray crystallography and the supramolecular arrangement was analyzed from Hirshfeld surface methodology. An iterative electrostatic scheme using a super molecule approach, where neighboring molecules are represented by charge points, was employed to investigate optical dipole moment (µ), the linear polarization (α) and the first (ß) and second (γ) hyperpolarizabilities. The NMZ crystallized in the centrosymetric space group P21/n and packs via combined O-H···O, C-H···O, and N···π interactions. The macroscopic property of third order χ(3) found for the NMZ is 298.62 times greater than values reported for chalcone derivative (2 E)-1-(3-bromophenyl)-3-[4 (methylsulfanyl)phenyl]prop-2-en-1-one. The results for NMZ indicate a good nonlinear optical effect.

A Green Protocol for Microwave-Assisted Extraction of Volatile Oil Terpenes from Pterodon emarginatus Vogel. (Fabaceae).

Microwave-assisted extraction of volatile oils (MAE) potentially offers a more efficient and bio-sustainable method than conventional extraction by Clevenger apparatus (CE). This study aimed to optimise the MAE of the volatile oil from Pterodon emarginatus fruits and characterise the volatile compounds. A 2³ full-factorial central composite design and response surface methodology were used to evaluate the effects of time (min), moisture (%) and microwave power (W) on the extraction yield. The process optimisation was based on the desirability function approach. The reaction time and moisture conditions were standardised in these analyses. The volatile oil composition was analysed by Gas Chromatography/Mass Spectrometry (GC/MS) in order to compare techniques extractions influences. Microwave irradiation showed excellent performance for extraction of the volatile oil from Pterodon emarginatus and there were some advantages in compare to conventional method with respect to the time (14 times), energy (6 times), reagents amounts and waste formation. About chemical composition presents significant differences with the type of extraction. Caryophyllene (25.65%) and trans-α-bisabolol (6.24%) were identified as major components in MAE sample while caryophyllene (6.75%) and γ-elemene (7.02%) are the components with higher relative percentage in CE samples. The microwaves assisted process shown an increase of economic interested compounds present in volatile oil.

Bioinspired-Metalloporphyrin Magnetic Nanocomposite as a Reusable Catalyst for Synthesis of Diastereomeric (-)-Isopulegol Epoxide: Anticancer Activity Against Human Osteosarcoma Cells (MG-63).

In the present study, we developed a green epoxidation approach for the synthesis of the diastereomers of (-)-isopulegol benzyl ether epoxide using molecular oxygen as the oxidant and a hybrid manganese(III)-porphyrin magnetic reusable nanocomposite as the catalyst. High activity, selectivity, and stability were obtained, with up to four recycling cycles without the loss of activity and selectivity for epoxide. The anticancer effect of the newly synthesized isopulegol epoxide diastereomers was evaluated on a human osteosarcoma cell line (MG-63); both diastereomers showed similar in vitro potency. The measured IC50 values were significantly lower than those reported for other monoterpene analogues, rendering these epoxide isomers as promising anti-tumor agents against low prognosis osteosarcoma.

Structural basis of antibacterial photodynamic action of curcumin against S. aureus.

Antimicrobial photodynamic therapy (aPDT) is an alternative tool to commercial antibiotics for the inactivation of pathogenic bacteria (e.g., S. aureus). However, there is still a lack of understanding of the molecular modeling of the photosensitizers and their mechanism of action through oxidative pathways. Herein, a combined experimental and computational evaluation of curcumin as a photosensitizer against S. aureus was performed. The radical forms of keto-enol tautomers and the energies of curcumin's frontier molecular orbitals were evaluated by density functional theory (DFT) to point out the photodynamic action as well as the photobleaching process. Furthermore, the electronic transitions of curcumin keto-enol tautomers were undertaken to predict the transitions as a photosensitizer during the antibacterial photodynamic process. Moreover, molecular docking was used to evaluate the binding affinity with the S. aureus tyrosyl-tRNA synthetase as the proposed a target for curcumin. In this regard, the molecular orbital energies show that the curcumin enol form has a character of 4.5% more basic than the keto form - the enol form is a more promising electron donor than its tautomer. Curcumin is a strong electrophile, with the enol form being 4.6% more electrophilic than its keto form. In addition, the regions susceptible to nucleophilic attack and photobleaching were evaluated by the Fukui function. Regarding the docking analysis, the model suggested that four hydrogen bonds contribute to the binding energy of curcumin's interaction with the ligand binding site of S. aureus tyrosyl-tRNA synthetase. Finally, residues Tyr36, Asp40, and Asp177 contact curcumin and may contribute to orienting the curcumin in the active area. Moreover, curcumin presented a photoinactivation of 4.5 log unit corroborating the necessity of the combined action of curcumin, light, and O2 to promote the photooxidation damage of S. aureus. These computational and experimental data suggest insights regarding the mechanism of action of curcumin as a photosensitizer to inactivate S. aureus bacteria.

Synthesis, characterization, and computational study of a new heteroaryl chalcone.

This work presents the synthesis of the chalcone (E)-3-(2,6-difluorophenyl)-1-(furan-2-yl)-prop-2-en-1-one molecule through the equimolar reaction between 1-(furan-2-yl)-ethenone and 2,6-difluorobenzaldehyde. The crystallographic characterization and the extensive theoretical study regarding electronic properties were obtained. The supramolecular arrangement was described by X-ray diffraction and Hirshfeld surfaces. Optimized geometrical structure was obtained by density functional theory, and the electronic study for differences between the solid and gas phases was carried out with M062-X at 6-311++G(2d,2p) basis set. Natural bond orbital, frontier molecular orbitals (HOMO-LUMO), and molecular electrostatic potential map were determined to elucidate the information related to the charge transfer in the molecule. The theoretical and experimental vibrational spectra were plotted, which included the IR intensities, the calculated and experimental vibrational frequencies, and the assigned vibrational modes for the main groups of DTP.

Solid state characterization and theoretical study of non-linear optical properties of a Fluoro-N-Acylhydrazide derivative.

In this work we determine the linear and non-linear optical properties of a Fluoro-N-Acylhydrazide derivative (FBHZ), using a combined supermolecule approach and an iterative scheme of electrostatic polarization, where the atoms of neighbouring molecules are represented by point charges. Our results for non-linear optics (NLO) are comparable to those found experimentally, suggesting that FBHZ constitutes an attractive object for future studies and for use as an interesting material for third-order NLO applications. The dynamic electrical properties of FBHZ in different solvent media are reported. Its molecular properties are closely related to supramolecular features; accordingly, we analysed all its crystal structure properties via intermolecular interactions in the solid state, using X-ray crystallography data and Hirshfeld surface (HS), including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and hot-stage microscopy (HSM), where the results reveal crystal stability in respect to temperature variation.

Conformation analysis of a novel fluorinated chalcone.

Chalcones are an important class of natural compounds that exhibit numerous biological activities. In this paper, we report the synthesis and characterization of new fluorinated chalcone (FCH). The molecular geometry was determined by means of single crystal X-ray diffraction, and density functional theory (DFT) at B3LYP, M06-2X functionals and MP2 method, with the 6-311++G(d,p) basis set, was applied to optimize the ground state geometry and to study the molecular conformational stability. The molecular electrostatic potential (MEP) was also investigated at the same level of theory in order to identify and quantify the possible reactive sites. The FCH crystallizes in the centrossymmetric space group [Formula: see text] with two independent conformers (α and ß) in the asymmetric unit cell. The α conformer is arranged in planar layer whereas the ß creates a layer of non-classical dimer along c axis, that differ from α in about 11° in the orientation of phenyl groups. The stabilization of the ß conformer is achieved by C-H···π arrangement. The small energy difference between the conformers (0.086 kcal mol-1) and the absence of activation energy indicates that the conversion between them can takes place at room temperature and the ß isomer is stable only in solid state. The FCH most electrophilic site occurs on the oxygen atom from the carboxyl group with absolute MEP value of about -52 kcal mol-1 whereas the MEP value calculated for F site is about -23 kcal mol-1.

Ecofriendly porphyrin synthesis by using water under microwave irradiation.

Water, under microwave irradiation and at a temperature of 473 K, reaches pressures above 16 bar, being capable to act as catalyst, without the use of organic solvents and oxidants, for meso-substituted porphyrin synthesis. Sustainability of the reaction is proved by E Factor=35 and EcoScale value of 50.5, the highest so far obtained for porphyrin synthesis. Methodology's wide versatility is clearly demonstrated by the good yields obtained for both aryl and alkyl substituted porphyrins. These reaction conditions represent a huge development, not only by using very high concentrations, minimizing organic solvent usage, but also by eradicating toxic expensive solvents and oxidants.

Synthesis, characterization, and computational study of a new dimethoxy-chalcone.

Chalcones are an important class of medicinal compounds and are known for taking part in various biological activities as in anti-inflammatory, anti-leishmania, antimitotic, and antiviral. Chemically, chalcones consist of open-chain flavonoids in which the two aromatic rings are joined by a three-carbon α,ß-unsaturated carbonyl system. The wide action spectrum has attracted our attention to synthesize, crystallize, and characterize the dimethoxy-chalcone C18H18O3. Aiming to understand the process of crystal lattice stabilization, a combination of technique has been used including X-ray diffraction, infrared spectroscopy and computational molecular modeling. The theoretical calculations were carried out by the density functional method (DFT) with the M06-2X functional, with the 6-311+G(d,p) basis set. The vibrational wavenumbers were calculated and the scaled values were compared with experimental FT-IR spectrum. The intermolecular interactions were quantified and intercontacts in the crystal structure were analyzed using Hirshfeld surfaces. Bond distances and angles described by the X-ray diffraction and theoretical calculation are very similar. The C-H….O contacts contributing to assemble the supramolecular architecture are also responsible for the molecular structure assembly.