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1.
Phys Chem Chem Phys ; 26(13): 10021-10028, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38482754

RESUMO

cis-2-tert-Butyl-5-(tert-butylsulfonyl)-1,3-dioxane (cis-1) exhibits a high degree of eclipsing in the H-C5-S-C segment in the solid state, the origin of which remains unexplained. The eclipsed conformation that corresponds to an energetic minimum in the solid state practically corresponds to a rotational transition state in solution, which allows an approach to understand transitions states. The difference in the enthalpy of sublimation ΔsubH between cis-1 and the more stable trans-1 is 8.40 kcal mol-1, lets to consider that the intermolecular interactions in the crystalline structure must be responsible for the conformational effect observed in the solid state. The study of the experimental electron density of cis-1 in solid state allowed to establish that CH⋯OS intermolecular interaction is the main contribution to the observed eclipsing. The charge density analysis was also performed using the quantum theory of atoms in molecules to evaluate the nature and relevance of the intermolecular interactions in the crystal structure.

2.
J Org Chem ; 89(5): 3092-3101, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38359145

RESUMO

We have developed a straightforward and rapid methodology for the synthesis of tetrasubstituted allenes bearing carboxylic acids in the 1,3-position through the gold(I)-catalyzed nucleophilic addition of bis(trimethylsilyl)ketene acetals to ynones. The reaction was evaluated with several substrates, and 21 allenes were obtained in moderate to good yields. Using DFT calculations, we studied the mechanism of the reaction, which suggested a nucleophilic 1,4-addition pathway. The potential of allenes to act as a source of highly functionalized lactones was also explored.

3.
Dalton Trans ; 53(5): 2231-2241, 2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38193761

RESUMO

We herein report the synthesis and catalytic application of a new family of dinuclear Cu(I) complexes based on [N,P]-pyrrole ligands. The Cu(I) complexes (4a-d) were obtained in good yields and their catalytic properties were evaluated in the1,3-dipolar cycloaddition of azomethine ylides and electron-deficient alkenes. The air-stable complexes 4a-d exhibited high endo-diasteroselectivity to obtain substituted pyrrolidines, and the catalytic system showed excellent reactivity and wide substitution tolerance.

4.
Int J Mol Sci ; 24(22)2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-38003515

RESUMO

The crystal structure determination of metal complexes of curcuminoids is a relevant topic to assess their unequivocal molecular structure. We report herein the first two X-ray crystal structures of homoleptic metal complexes of a curcuminoid, namely Dimethoxycurcumin (DiMeOC), with gallium and indium. Such successful achievement can be attributed to the suppression of interactions from the phenolic groups, which favor an appropriate molecular setup, rendering Dimethoxycurcumin gallium ((DiMeOC)2-Ga) and Dimethoxycurcumin indium ((DiMeOC)3-In) crystals. Surprisingly, the conformation of ligands in the crystal structures shows differences in each metal complex. Thus, the ligands in the (DiMeOC)2-Ga complex show two different conformers in the two molecules of the asymmetric unit. However, the ligands in the (DiMeOC)3-In complex exhibit three different conformations within the same molecule of the asymmetric unit, constituting the first such case described for an ML3 complex. The cytotoxic activity of the (DiMeOC)2-Ga complex is 4-fold higher than cisplatin against the K562 cell line and has comparable activity towards U251 and PC-3 cell lines. Interestingly, this complex exhibit three times lesser toxicity than cisplatin and even slightly lesser cytotoxicity than curcumin itself.


Assuntos
Antineoplásicos , Complexos de Coordenação , Gálio , Gálio/farmacologia , Gálio/química , Complexos de Coordenação/farmacologia , Complexos de Coordenação/química , Cisplatino , Índio/química , Diarileptanoides , Linhagem Celular Tumoral , Ligantes , Antineoplásicos/farmacologia
5.
Molecules ; 28(16)2023 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-37630284

RESUMO

The first single crystal structure of the homoleptic copper (II) ML2 complex (M=Cu (II), L = curcumin) was obtained and its structure was elucidated by X-ray diffraction showing a square planar geometry, also confirmed by EPR. The supramolecular arrangement is supported by C-H···O interactions and the solvent (MeOH) plays an important role in stabilizing the crystal packing Crystallinity was additionally assessed by XRD patterns. The log P value of the complex (2.3 ± 0.15) was determined showing the improvement in water solubility. The cytotoxic activity of the complex against six cancer cell lines substantially surpasses that of curcumin itself, and it is particularly selective against leukemia (K562) and human glioblastoma (U251) cell lines, with similar antioxidant activity to BHT. This constitutes the first crystal structure of pristine curcumin complexed with a metal ion.

6.
Fitoterapia ; 169: 105593, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37355051

RESUMO

From the bioactive extract of the euphorbiaceous Croton niveus Jacq., three previously unreported ent-rosane diterpenes have been isolated and characterized by conventional methods, in addition to the known compounds lupeol, cajucarinolide and some phytosterols. Two of the ent-rosane diterpenes displayed activity against HCT-15 and PC-3 cancer cell lines, and the results of docking calculations of these compounds with NF-κB and STAT3 receptors agreed with the proposed mode of action of diterpenes against PC-3 cells.


Assuntos
Antineoplásicos , Croton , Diterpenos do Tipo Caurano , Diterpenos , Euphorbiaceae , Estrutura Molecular , Diterpenos/farmacologia , Antineoplásicos/farmacologia
7.
Molecules ; 28(3)2023 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-36771102

RESUMO

We report herein the synthesis and characterization of three heterocyclic curcuminoid ligands and their homoleptic metal complexes with magnesium and copper. Thus, N-methyl-2-pyrrolecarboxaldehyde, Furan-2-carboxaldehyde, and 2-Thiophenecarboxaldehyde were condensed with 2,4-pentanedione-boron trioxide complex. The first N-methyl-2-pyrrole curcuminoid and its Mg(II) complex are reported. All curcuminoid ligands and their corresponding metal complexes were characterized by infrared spectroscopy (IR), liquid state nuclear magnetic resonance (LSNMR), electron paramagnetic resonance (EPR), mass spectrometry (MS) and single crystal X-ray diffraction (SCXRD). The ThiopheneCurc-Cu (9) constitutes the first case of a "conformationally-heteroleptic" complex. The unique six-peaks star arrangement for the ThiopheneCurc ligand derived from the supramolecular description is reported. The metal complexes of FuranCurc-Mg (5) and ThiopheneCurc-Cu (9) have a good antioxidant effect (IC50 = 11.26 ± 1.73 and 10.30 ± 0.59 µM), three and two times higher than their free ligands respectively. Additionally, (5) shows remarkable cytotoxicity against colon cancer adenocarcinoma cell line HCT-15, comparable to that of cisplatin, with a negligible toxic effect in vitro towards a healthy monkey kidney cell line (COS-7).


Assuntos
Antineoplásicos , Complexos de Coordenação , Diarileptanoides , Complexos de Coordenação/química , Cisplatino , Antioxidantes/farmacologia , Espectroscopia de Ressonância de Spin Eletrônica , Cobre/química , Cristalografia por Raios X , Ligantes , Antineoplásicos/química
8.
Acta Crystallogr E Crystallogr Commun ; 78(Pt 8): 818-820, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35974822

RESUMO

The title compound, [Fe(C5H5)(C8H7N2S)], was synthesized by the direct reaction of acetyl-ferrocene, thio-urea and resublimed iodine. The structure shows one mol-ecule in the asymmetric unit. The amino-thia-zole ring makes an angle of 14.53 (13)° with the ferrocenyl ring to which it is attached. In the crystal, pairs of complex mol-ecules inter-act via inter-molecular N-H⋯N hydrogen bonds, forming a cyclic dimer which then inter-acts with other dimers through C-H⋯π inter-actions.

9.
J Org Chem ; 86(14): 9540-9551, 2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34210132

RESUMO

The cyclopropane ring-opening reaction of riolozatrione, a natural product obtained from Jatropha dioica, afforded a 2,2-disubstituted 1,3-cyclohexandione displaying an alkyl methyl ether group at position 5. The conformational analysis of this product showed a high preference for the trans-diaxial conformation in both solution and solid state. Such conformation was possible from the noncovalent intramolecular nX → π*C═O interactions (X = an element having an unshared electron pair), allowing the determination of the interaction energies. Since the nX → π*C═O interactions can be regarded as additive, the energy values ranged from 4.52 to 6.51 kcal mol-1 for each carbonyl group with a strong dependency on the interatomic distances. The rigorous analysis of the electron density in the topological theory of atoms in molecules framework clearly shows that the origin of O-C═O interactions are through the nO → π*C═O electron transfer mechanism. Such interactions are slightly weaker than a canonical hydrogen bond but seemingly stronger than a van der Waals interaction. This interaction must be considered as a stereoelectronic effect due the electronic transfer between the interacting groups, which are limited by their relative stereochemistry and can be represented by a bond-no bond interaction, causing the pyramidalization of the carbonyl, which is the charge acceptor group.

10.
Molecules ; 25(14)2020 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-32674349

RESUMO

Curcumin, the most important secondary metabolite isolated from Curcuma longa, is known for its numerous purported therapeutic properties and as a natural dye. Herein, based on curcumin's intrinsic fluorescence, a search for improved curcumin-based fluorophores was conducted. Within the set of semi-synthetic curcumin derivatives i.e. mono (1), di (2), tri (3), tetra (4) benzylated and dibenzyl-fluoroborate (5), the fluorescence properties of 2 and 5 in solution outstood with a two-fold quantum yield compared to curcumin. Furthermore, all benzylated derivatives showed a favorable minimal cytotoxic activity upon screening at 25 µM against human cancer and non-tumoral COS-7 cell lines, with a reduction of its cytotoxic effect related to the degree of substitution. Fluorophores 2 and 5 are versatile bioimaging tools, as revealed by Confocal Fluorescence Microscopy (CFM), and showed permeation of living cell membranes of astrocytes and astrocytomas. When 2 is excited with a 405- (blue) or 543-nm (green) laser, it is possible to exclusively and intensively visualize the nucleus. However, the fluorescence emission fades as the laser wavelength moves towards the red region. In comparison, 5 allows selective visualization of cytoplasm when a 560-nm laser is used, showing emission in the NIR region, while it is possible to exclusively observe the nucleus at the blue region with a 405-nm laser.


Assuntos
Núcleo Celular , Citoplasma , Diarileptanoides/química , Diarileptanoides/farmacologia , Corantes Fluorescentes/química , Corantes Fluorescentes/farmacologia , Imagem Molecular , Núcleo Celular/metabolismo , Curcumina/química , Curcumina/farmacologia , Citoplasma/metabolismo , Modelos Moleculares , Conformação Molecular , Imagem Molecular/métodos , Estrutura Molecular
11.
Phytochemistry ; 169: 112180, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31634725

RESUMO

Both DNA barcoding and phylogenetic data of the studied botanical material suggested the existence a new population of Galphimia glauca. Their leaves afforded three new nor-3,4-seco-friedelanes named galphimines M-O, together with known galphimines D, E, G, and I. Galphimines M and N possess bicyclic orthoacetates which are the first examples of orthoesters found in the Malpighiaceae family, while galphimine O has a 27,20-δ-lactone moiety. The structures elucidation followed from spectroscopic means and the absolute configuration followed from single crystal X-ray diffraction analyses. Tests for antibacterial and antifungal activities of galphimines N and M showed no promising effects.


Assuntos
Galphimia/química , Triterpenos/química , Cristalografia por Raios X , Modelos Moleculares , Conformação Molecular , Triterpenos/isolamento & purificação
12.
Org Lett ; 21(18): 7460-7465, 2019 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-31497973

RESUMO

Several phthalides were semisynthesized, including a 3,8-dihydrodiligustilide with progesterone-like activity, previously isolated from Ligusticum chuanxiong, the structure of which was earlier assigned to a semisynthetic product with nonidentical spectroscopic constants. The structure of this natural phthalide was reassigned with a proposal of its absolute configuration. Phthalides acted as progestins in cell viability assays, immunofluorescence microscopy, and docking analysis. Therefore, the structures for natural and semisynthetic phthalides with potential use in hormone-related therapies were reassigned.

13.
J Nat Prod ; 82(9): 2489-2500, 2019 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-31429569

RESUMO

Chemical investigation of the aerial parts (except fruits and calixes) of Physalis nicandroides var. attenuata led to the isolation of a series of new labdane-type diterpenoids, including the closely related compounds 1-3, the labdane glucosides 4 and 5, a mixture of the epimeric alcohols 6 and 7, and one labdanetriol, isolated as its tri-O-acetyl derivative 9. In addition, three new withanolides (14-16) and six known compounds were isolated. The structures of these compounds were elucidated by analysis of their spectroscopic data and chemical transformations, and those of compounds 1, 4, and 16 were confirmed by X-ray diffraction analysis of the natural product (1) and of the corresponding acetyl derivatives 4a and 16a. Fourteen of these compounds were assayed for their in vitro inhibitory activity against yeast α-glucosidase and acetylcholinesterase enzymes. The results were negative in both cases, except for compound 3a that marginally inhibited the activity of acetylcholinesterase with an IC50 value of 64.4 µM.


Assuntos
Diterpenos/isolamento & purificação , Physalis/química , Vitanolídeos/isolamento & purificação , Cristalografia por Raios X , Estrutura Molecular , Análise Espectral/métodos
14.
Molecules ; 24(5)2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30841623

RESUMO

We report herein the synthesis and crystal structures of five new homoleptic copper complexes of curcuminoids. The scarcity of reports of homoleptic complex structures of curcuminoids is attributed to the lack of crystallinity of such derivatives, and therefore, their characterization by single crystal X-ray diffraction is rare. The ligand design suppressing the phenolic interaction by esterification or etherification has afforded a significant increase in the number of known crystal structures of homoleptic metal complexes of curcuminoids revealing more favorable crystallinity. The crystal structures of the present new copper complexes show four-fold coordination with a square planar geometry. Two polymorphs were found for DiBncOC-Cu when crystallized from DMF. The characterization of these new complexes was carried out using infrared radiation (IR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), and single crystal X-ray diffraction (SCXRD) and the antioxidant and cytotoxic activity of the obtained complexes was evaluated.


Assuntos
Complexos de Coordenação/química , Cobre/química , Animais , Antioxidantes/síntese química , Antioxidantes/química , Antioxidantes/farmacologia , Linhagem Celular Tumoral , Complexos de Coordenação/síntese química , Complexos de Coordenação/farmacologia , Relação Dose-Resposta a Droga , Ligantes , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Ratos , Análise Espectral
15.
Molecules ; 23(4)2018 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-29587345

RESUMO

A new series of Fischer carbenes have been synthetized and examined as hole-transporting or electron-transporting layers (HTLs or ETLs) in the fabrication of organic solar cells (OSCs). The synthesis of three Fischer aminocarbene complexes with the general formula [Cr(CO)5{C(NHCH2)Ar}] (Ar = 2-pyridyl (3a), 3-pyridyl (3b) and 4-pyridyl (3c)) is reported. The molecular structure of complex 3b has been confirmed by X-ray analysis. In order to study the possible applications of the three Fischer aminocarbenes in OSCs, thin films of these complexes were prepared using a vacuum deposition process. These organometallic films were chemically and morphologically characterized by IR spectroscopy, SEM, AFM and XRD. According to the IR and Tauc analysis, the vacuum deposition process generates thin films free of impurities with an activation energy of 4.0, 2.7 and 2.1 eV for 3a, 3b y 3c, respectively. The UV-vis spectra of the amorphous aminocarbene films show that they are practically transparent to the visible radiation of the electromagnetic spectrum. This is due to the fact that their absorption is located mainly in the ultraviolet range. Two OSCs with bulk-heterojunction configuration were manufactured in order to prove the use of the aminocarbenes as ETL o HTL. The aminocarbene [Cr(CO)5{C(NHCH2) 4-pyridyl}] (3c) proved to be suitable as ETL with a fill factor (FF) of 0.23 and a short circuit current density (JSC) of 1.037 mA/cm².


Assuntos
Alcinos/química , Dioxolanos/química , Compostos Organometálicos/síntese química , Cristalografia por Raios X , Transporte de Elétrons , Estrutura Molecular , Compostos Organometálicos/química , Energia Renovável , Energia Solar
16.
J Nat Prod ; 80(11): 3003-3009, 2017 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-29135252

RESUMO

Eleven neo-clerodane diterpenoids (1-11) including the new analogues 1, 2, and 10, and 3',5,6,7-tetrahydroxy-4'-methoxyflavone (12) were isolated from the aerial parts of Salvia polystachya. Polystachyne G (1) and 15-epi-polystachyne G (2) were isolated as an epimeric mixture, containing a 5-hydroxyfuran-2(5H)-one unit in the side chain at C-12 of the neo-clerodane framework. Polystachyne H (10) contains a 1(10),2-diene moiety and a tertiary C-4 hydroxy group. The structures of these compounds were established by analysis of their NMR spectroscopic and MS spectrometric data. The absolute configurations of compounds 3, 4, and 10 were determined through single-crystal X-ray diffraction analysis. The antibacterial, antifungal, and phytotoxic activities of the diterpenoids were determined. In addition, the stimulatory effect of the expression of extracellular matrix components of nine of the isolates (1-8 and 11) was assayed. Compounds 1-4, 8, and 11 increased the expression of the genes codifying for type I, type III, and type V collagens and for elastin.


Assuntos
Diterpenos Clerodânicos/isolamento & purificação , Diterpenos Clerodânicos/farmacologia , Matriz Extracelular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Salvia/química , Bacillus/efeitos dos fármacos , Candida albicans/efeitos dos fármacos , Colágeno/efeitos dos fármacos , Colágeno/genética , Cristalografia por Raios X , Diterpenos Clerodânicos/química , Elastina/efeitos dos fármacos , Elastina/genética , Escherichia coli/efeitos dos fármacos , Flavonoides/química , Flores/química , Humanos , México , Testes de Sensibilidade Microbiana , Conformação Molecular , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Folhas de Planta/química , Reação em Cadeia da Polimerase
18.
Fitoterapia ; 114: 1-6, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27542708

RESUMO

Three new diterpenes (amarissinins A-C, 1-3) containing several oxygenated functionalities were isolated from the leaves and flowers of Salvia amarissima. The structures of these compounds were established through the analysis of their NMR spectroscopy and mass spectrometry data. The structures of compounds 1 and 2 were confirmed by single crystal X-ray diffraction. Compound 2 was identified as a C-10 epimer of dugesin F (5). The cytotoxic activity of these compounds against five human cancer cell lines was determined. Additionally, the capability to modulate the multidrug resistance (MDR) in the MCF-7 cancer cell line resistant to vinblastine was tested.


Assuntos
Antineoplásicos Fitogênicos/química , Diterpenos Clerodânicos/química , Salvia/química , Antineoplásicos Fitogênicos/isolamento & purificação , Cristalografia por Raios X , Diterpenos Clerodânicos/isolamento & purificação , Resistência a Múltiplos Medicamentos , Ensaios de Seleção de Medicamentos Antitumorais , Flores/química , Humanos , Células MCF-7 , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Folhas de Planta/química
19.
Acta Crystallogr E Crystallogr Commun ; 71(Pt 10): 1230-5, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26594414

RESUMO

In the crystals of the title N-halo-methyl-ated quaternary ammonium salts, C19H23IN(+)·I(-), (I) [systematic name: N-(4,4-di-phenyl-but-3-en-1-yl)-N-iodo-methyl-N,N-di-methyl-ammonium iodide], C20H25IN(+)·I(-), (II) [systematic name: N-(5,5-di-phenyl-pent-4-en-1-yl)-N-iodo-methyl-N,N-di-methyl-ammonium iodide], and C21H27IN(+)·I(-), (III) [systematic name: N-(6,6-di-phenyl-hex-5-en-1-yl)-N-iodo-methyl-N,N-di-methyl-ammonium iodide], there are short I⋯I(-) inter-actions of 3.564 (4), 3.506 (1) and 3.557 (1) Šfor compounds (I), (II) and (III), respectively. Compound (I) crystallizes in the Sohncke group P21 as an 'enanti-opure' compound and is therefore a potential material for NLO properties. In the crystal of compound (I), mol-ecules are linked by C-H⋯I(-) and C-H⋯π inter-actions which, together with the I⋯I(-) inter-actions, lead to the formation of ribbons along [100]. In (II), there are only C-H⋯I(-) inter-actions which, together with the I⋯I(-) inter-actions, lead to the formation of helices along [010]. In (III), apart from the I⋯I(-) inter-actions, there are no significant inter-molecular inter-actions present.

20.
Magn Reson Chem ; 53(10): 860-5, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26255633

RESUMO

The leaves of Piscidia carthagenensis provided new 7,2',5'-trimethoxy-3',4'-methylenedioxyisoflavone (1), admixed with known 6,7-dimethoxy-3',4'-methylenedioxyisoflavone (2), and 5,4'-dihydroxy-7,2',5'-trimethoxyisoflavone (3), which were separated by extensive fractional solubillization. Selective irradiation of the H-5 "singlet" of 2 allowed distinction of the two methoxy group signals, whose chemical shift difference is only 0.004 ppm (1.2 Hz at 300 MHz). The (1)H and (13)C NMR data of 3 were assigned with the aid of HETCOR and gHMBC measurements. Although 1 looked inhomogeneous in the solid state, its solution structure followed from (1)H NMR measurements, where it looked homogeneous. To clarify the solid state aspect and confirm the structure of 1, two types of crystals were mechanically separated and subjected to single crystal X-ray diffraction measurements. This study revealed polymorphism because of the concomitant presence of orthorhombic and triclinic crystals, but showed no atropisomerism. The structure of 3 was also verified by X-ray diffraction crystallography.


Assuntos
Isoflavonas/química , Espectroscopia de Ressonância Magnética , Hidrogênio , Estrutura Molecular , Difração de Raios X
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