Access and Modulation of Substituted Pyrrolo[3,4-c]pyrazole-4,6-(2H,5H)-diones.

The first access to polyfunctionnalized pyrrolo[3,4-c]pyrazole-4,6-(2H,5H)-dione derivatives is reported. The series were generated from diethyl acetylenedicarboxylate and arylhydrazines, which afforded the key intermediates bearing two functional positions. The annellation to generate the maleimide moiety of the bicycle was studied. Moreover, an efficient palladium-catalyzed C-C and C-N bond formation via Suzuki-Miyaura or Buchwald-Hartwig coupling reactions in C-6 position was investigated from 6-chloropyrrolo[3,4-c]pyrazole-4,6-(2H,5H)-diones. This method provides novel access to various 1,6 di-substituted pyrrolo[3,4-c] pyrazole-4,6-(2H,5H)-diones.

Efficient Synthesis of 1H-Benzo[4,5]imidazo[1,2-c][1,3]oxazin-1-one Derivatives Using Ag2CO3/TFA-Catalyzed 6-endo-dig Cyclization: Reaction Scope and Mechanistic Study.

A small library of 1H-benzo[4,5]imidazo[1,2-c][1,3]oxazin-1-one derivatives was prepared in good to excellent yields, involving a Ag2CO3/TFA-catalyzed intramolecular oxacyclization of N-Boc-2-alkynylbenzimidazole substrates. In all experiments, the 6-endo-dig cyclization was exclusively achieved since the possible 5-exo-dig heterocycle was not observed, indicating the high regioselectivity of this process. The scope and limitations of the silver catalyzed 6-endo-dig cyclization of N-Boc-2-alkynylbenzimidazoles as substrates, bearing various substituents, were investigated. While ZnCl2 has shown limits for alkynes with an aromatic substituent, Ag2CO3/TFA demonstrated its effectiveness and compatibility regardless of the nature of the starting alkyne (aliphatic, aromatic or heteroaromatic), providing a practical regioselective access to structurally diverse 1H-benzo[4,5]imidazo[1,2-c][1,3]oxazin-1-ones in good yields. Moreover, the rationalization of oxacyclization selectivity in favor of 6-endo-dig over 5-exo-dig was explained by a complementary computational study.

Near-Infrared Emitting Poly(amidoamine) Dendrimers with an Anthraquinone Core toward Versatile Non-Invasive Biological Imaging.

Today, there is a very strong demand for versatile near-infrared (NIR) imaging agents suitable for non-invasive optical imaging in living organisms (in vivo imaging). Here, we created a family of NIR-emitting macromolecules that take advantage of the unique structure of dendrimers. In contrast to existing fluorescent dendrimers bearing fluorophores at their periphery or in their cavities, a NIR fluorescent structure is incorporated into the core of the dendrimer. Using the poly(amidoamine) dendrimer structure, we want to promote the biocompatibility of the NIR-emissive system and to have functional groups available at the periphery to obtain specific biological functionalities such as the ability to deliver drugs or for targeting a biological location. We report here the divergent synthesis and characterization by NMR and mass spectrometries of poly(amidoamine) dendrimers derived from the fluorescent NIR-emitting anthraquinone core (AQ-PAMAF). AQ-PAMAFs ranging from the generation -0.5 up to 3 were synthesized with a good level of control resulting in homogeneous and complete dendrimers. Absorption, excitation, and emission spectra, as well as quantum yields, of AQ-PAMAFs have been determined in aqueous solutions and compared with the corresponding properties of the AQ-core. It has been demonstrated that the absorption bands of AQ-PAMAFs range from UV to 750 nm while emission is observed in the range of 650-950 nm. Fluorescence macroscopy experiments confirmed that the NIR signal of AQ-PAMAFs can be detected with a satisfactory signal-to-noise ratio in aqueous solution, in blood, and through 1 mm thick tissue-mimicking phantom. The results show that our approach is highly promising for the design of an unprecedented generation of versatile NIR-emitting agents.

A Ag2CO3/TFA-catalyzed intramolecular annulation approach to imidazo[1,2-c][1,3]oxazin-5-one derivatives.

A series of 2,7-disubstituted 3-methylimidazo[1,2-c][1,3]oxazin-5-ones were synthesized in good yields via Ag2CO3/TFA-mediated intramolecular annulation of N-Boc-2-alkynyl-4-bromo(alkynyl)-5-methylimidazoles. This methodology was carried out in the presence of a catalytic amount of silver carbonate and trifluoroacetic acid in dichloroethane at 60 °C. In all experiments, only the six-membered ring product was obtained since the possible five-membered compound was not observed, proving the high regioselectivity of this approach. A complementary computational study was performed in order to rationalize the mechanism of 6-endo-dig heterocycle formation. In addition, 2-bromo-3-methyl-7-phenylimidazo[1,2-c][1,3]oxazin-5-one was used as a building block to synthesize a small library of new 2-substituted imidazo[1,2-c][1,3]oxazin-5-one derivatives through the Suzuki, Sonogashira and Heck cross coupling reactions.

Antifungal and Cytotoxic Activity of Diterpenes and Bisnorsesquiterpenoides from the Latex of Euphorbia resinifera Berg.

Euphorbia resinifera latex has been extensively utilized in traditional medicine due to its range of bioactivities. Chromatographic separations on silica gel of ethanol extract of E. resinifera latex led to the development of a new procedure for isolating resiniferatoxin (4) via dried E. resinifera latex and the identification of nine compounds. Among these, catechol (7), protocatechuic acid (8) and 3,4-dihydroxyphenylacetic acid (9), known phenolic compounds, were identified for the first time in E. resinifera latex. Herein we investigated the effects of major compounds of the latex of E. resinifera on the yeast Saccharomyces cerevisiae, on the growth of Aspergillus carbonarius, a widespread fungal contaminant, and on the breast cancer cell line MCF7 as well as on MCF10A normal breast cells. 12-deoxyphorbol-13-isobutyrate-20-acetate (2) had an inhibiting effect on the growth of A. carbonarius, and 7-p-metoxyphenylacetate-3,8,12-triacetate ingol (3) showed a negative effect on yeast cell growth and also a cytotoxic effect on breast cancer cell line MCF7, but not on MCF10A cells. Deglucosyl euphorbioside A (5) and euphorbioside A (6) showed a discoloration effect that was possibly related to mitochondrial functionality in yeast, and also cytotoxicity only on the cancer cell line that was tested. Interestingly, treatment of MCF7 cells with 7-p-metoxyphenylacetate-3,8,12-triacetate ingol (3) and deglucosyl euphorbioside A (5) not only led to a specific cytotoxic effect but also to the increase in the level of intracellular ROS.

Design, synthesis, and evaluation of cytotoxic activities of arylnaphthalene lignans and aza-analogs.

A concise and versatile synthetic strategy for the total synthesis of arylnaphthalene lignans and aza-analogs was developed. The main objective was to develop synthetic tactics for the creation of the lactone and lactam unit that would give access to an array of synthetic, natural, and/or bioactive compounds through rather simple chemical manipulation. The flexibility and potentiality of these new processes were further illustrated by the total synthesis of retrojusticidin B (13b), justicidin C (14b), and methoxy-vitedoamine A (22a). In this study, a series of novel aryl-naphthalene lignans and aza-analogs were synthesized, and the cytotoxic activities of all compounds on cancer cell growth were evaluated. The target compounds were structurally characterized by 1 H NMR (nuclear magnetic resonance), 13 C NMR, infrared, high-resolution mass spectrometry, and X-ray crystallography. The IC50 values of these compounds on five tumor cell lines (A549, HS683, MCF-7, SK-MEL-28, and B16-F1) were obtained by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) colorimetric assay. Five of the compounds exhibited excellent activity compared to 5-fluorouracil and etoposide against the five cell lines tested, with IC50 values ranging from 1 to 10 µM.

Efficient Access to 3,5-Disubstituted 7-(Trifluoromethyl)pyrazolo[1,5-a]pyrimidines Involving SNAr and Suzuki Cross-Coupling Reactions.

An efficient and original synthesis of various 3,5-disubstituted 7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidines is reported. A library of compounds diversely substituted in C-3 and C-5 positions was easily prepared from a common starting material, 3-bromo-7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidin-5-one. In C-5 position, a SNAr type reaction was achieved by first activating the C-O bond of the lactam function with PyBroP (Bromotripyrrolidinophosphonium hexafluorophosphate), followed by the addition of amine or thiol giving monosubstituted derivatives, whereas in C-3 position, arylation was performed via Suzuki-Miyaura cross-coupling using the commercially available aromatic and heteroaromatic boronic acids. Moreover, trifluoromethylated analogues of potent Pim1 kinase inhibitors were designed following our concise synthetic methodology.

"On Water" Palladium Catalyzed Direct Arylation of 1H-Indazole and 1H-7-Azaindazole.

The C3 direct arylation of 1H-indazole and 1H-7-azaindazole has been a significant challenge due to the lack of the reactivity at this position. In this paper, we describe a mild and an efficient synthesis of new series of C3-aryled 1H-indazoles and C3-aryled 1H-7-azaindazoles via a C3 direct arylation using water as solvent. On water, PPh3 was effective as a ligand along with a lower charge of the catalyst Pd(OAc)2 (5 mol%) at 100 °C, leading to C3-aryled 1H-indazoles or C3-aryled 1H-7-azaindazoles in moderate to good yields.

Regioselective Synthesis of New 2,4-(Het)aryl-3H-pyrido[1',2':1,5]pyrazolo[4,3-d]pyrimidines Involving Palladium-Catalyzed Cross-Coupling Reactions.

The design of some novel di-(het)arylated-3H-pyrido[1',2':1,5]pyrazolo[4,3-d]pyrimidine derivatives is reported. The series was developed from 1-aminopyridinium iodide, which afforded the key intermediate bearing two thiomethyl and amide functions, each of them useful for palladium catalyzed cross coupling reactions by alkyl sulfur release and C-O activation, respectively. The two regioselective and successive cross-coupling reactions were first carried out in C-4 by in situ C-O activation and next in C-2 by a methylsulfur release. Process optimization furnished conditions leading to products in high yields. The scope and limitations of the methodologies were evaluated and the final compounds characterized.

Synthetic Modification of 9α- and 9ß-Hydroxyparthenolide by Heck or Acylation Reactions and Evaluation of Cytotoxic Activities.

Motivated by the widely reported anticancer activity of parthenolides and their derivatives, a series of new substituted parthenolides was efficiently synthesized. Structural modifications were performed at the C-9 and C-13 positions of 9α- and 9ß-hydroxyparthenolide, which were isolated from the aerial parts of Anvillea radiata. Twenty-one derivatives were synthesized and evaluated for their in vitro cytotoxic activity against HS-683, SK-MEL-28, A549, and MCF-7 human cancer cell lines using the MTT colorimetric assay. Among the derivatives, seven exhibited excellent activity compared to 5-fluorouracil and etoposide against the four cell lines tested, with IC50 values ranging from 1.1 to 9.4 µM.

Modification of Natural Eudesmane Scaffolds via Mizoroki-Heck Reactions.

The Mizoroki-Heck reaction was applied to substrates derived from isocostic and ilicic acids, important sesquiterpene components of Dittrichia viscosa L. Greuter that were extracted directly from plant material collected in Morocco. After optimization of the metallo-catalysis conditions, various aryl-groups were successfully introduced on the exocyclic double bond with an exclusive E-configuration and without racemization.

Synthesis and biological evaluation of 9α- and 9ß-hydroxyamino-parthenolides as novel anticancer agents.

A series of 9α-hydroxyamino-parthenolides 3-10, 9ß-hydroxyamino-parthenolides 11-13 and 9α-hydroxy-1ß,10α-epoxyamino-parthenolides 15-19 were efficiently synthesized starting from 9α-hydroxyparthenolide 1 and 9ß-hydroxyparthenolide 2, which were isolated from Anvillea radiata. Compounds 1-13 and 15-19 were evaluated for their in vitro anticancer activity by the MTT colorimetric assay against one murine and six human cancer cell lines. This work provides new details about the structural requisites for anticancer activity.

Improvement of humic acid (HA) removal using a new inorganic-organic composite coagulant: α-costic acid as a modifier of polyaluminum chloride properties.

In this work, α-costic acid (αCA), a plant sesquiterpenoid from Dittrichia viscosa, was grafted into polyaluminum chloride (PAC), forming a new eco-sustainable composite coagulant PAC-αCA with improved functionality. The α-costic acid fraction grafted into the PAC and the distribution of aluminum forms in the composite coagulant were evaluated for their effectiveness in removing bentonite and humic acid from synthetic water. The interaction mechanism between PAC and α-CA was examined by the Al-Ferron time spectrophotometric method, density functional theory (DFT), and FTIR analysis. By monitoring the aluminum speciation in the composite coagulant PAC-αCA, it was discovered that the introduction of α-CA impacted the distribution of various aluminum forms, including mononuclear Ala, highly polymeric Alb, colloidal, and medium polymeric Alc. The theoretical analysis identified the Alb species as particularly sensitive to reacting with α-CA. Furthermore, coagulation performance tests demonstrated that increasing the percentage of α-CA and promoting the prevalence of Alb and Alc species over Ala species in PAC-αCA led to improved removal of turbidity and UV254. This study provides an attractive and practical option for water treatment plants to remove colloidal suspensions in raw water effectively.

Design, Synthesis, and Biological Evaluation of Novel Tomentosin Derivatives in NMDA-Induced Excitotoxicity.

N-methyl-D-aspartate (NMDA) receptor stimulation may lead to excitotoxicity, which triggers neuronal death in brain disorders. In addition to current clinical therapeutic approaches, treatment strategies by phytochemicals or their derivatives are under investigation for neurodegenerative diseases. In the present study, novel amino and 1,2,3-triazole derivatives of tomentosin were prepared and tested for their protective and anti-apoptotic effects in NMDA-induced excitotoxicity. Amino-tomentosin derivatives were generated through a diastereoselective conjugate addition of several secondary amines to the α-methylene-γ-butyrolactone function, while the 1,2,3-triazolo-tomentosin was prepared by a regioselective Michael-type addition carried out in the presence of trimethylsilyl azide (TMSN3) and the α-methylene-γ-lactone function. The intermediate key thus obtained underwent 1,3-dipolar Huisgen cycloaddition using a wide range of terminal alkynes. The possible effects of the derivatives on cell viability and free-radical production following NMDA treatment were measured by Water-Soluble Tetrazolium Salts (WST-1) and Dichlorofluorescein Diacetate (DCF-DA) assays, respectively. The alterations in apoptosis-related proteins were examined by Western blot technique. Our study provides evidence that synthesized triazolo- and amino-tomentosin derivatives show neuroprotective effects by increasing cellular viability, decreasing ROS production, and increasing the Bcl-2/Bax ratio in NMDA-induced excitotoxicity. The findings highlight particularly 2e, 2g, and 6d as potential regulators and neuroprotective agents in NMDA overactivation.

Molecular Characterization of Gene-Mediated Resistance and Susceptibility of ESKAPE Clinical Isolates to Cistus monspeliensis L. and Cistus salviifolius L. Extracts.

Background: Multidrug resistance (MDR) and extensively drug-resistant (XDR) are now the biggest threats to human beings. Alternative antimicrobial regimens to conventional antibiotic paradigms are extensively searched. Although Cistus extracts have long been used for infections in traditional folk medicines around the world, their efficacy against resistant bacteria still needs to be elucidated. We aim to investigate the antibiotic susceptibility profiles of clinical strains Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae (acronym "ESKAPE"), and their resistance mechanisms by PCR, as well as their sensitivity to C. monspeliensis (CM) and C. salviifolius (CS) methanol extracts and their fractions. Methods: Antibiotic susceptibility profile and resistance mechanism were done by antibiogram and PCR. Fractions of CM and CS were obtained using maceration and Soxhlet; their antibacterial activities were evaluated by determining inhibition zone diameter (IZD), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). Results: Results revealed that all strains were XDR except S. aureus, which was MDR. The PCR indicates the presence of gene-mediated resistance (bla CTX-M, bla SHV, bla OXA-48, bla NDM, bla OXA-51, bla OXA-58, bla IMP, bla VIM, and bla mecA). Also, maceration was slightly better for bioactivity preservation. Overall, the extracts of CM (IZD = 20 mm, MIC = 0.01 mg/mL) were more active than those of CS. All extracts inhibited MRSA (methicillin-resistant Staphylococcus aureus) and ERV (Enterococcus faecium Vancomycin-Resistant) with interesting MICs. The ethyl acetate fraction manifested great efficacy against all strains. Monoterpene hydrocarbons and sesquiterpenes oxygenated were the chemical classes of compounds dominating the analyzed fractions. Viridiflorol was the major compound in ethyl acetate fractions of 59.84% and 70.77% for CM and CS, respectively. Conclusions: The superior activity of extracts to conventional antibiotics was seen for the first time in the pathogens group, and their bactericidal effect could be a promising alternative for developing clinical antibacterial agents against MDR and XDR ESKAPE bacteria.

D-π-A-Type Pyrazolo[1,5-a]pyrimidine-Based Hole-Transporting Materials for Perovskite Solar Cells: Effect of the Functionalization Position.

Donor−acceptor (D−A) small molecules are regarded as promising hole-transporting materials for perovskite solar cells (PSCs) due to their tunable optoelectronic properties. This paper reports the design, synthesis and characterization of three novel isomeric D-π-A small molecules PY1, PY2 and PY3. The chemical structures of the molecules consist of a pyrazolo[1,5-a]pyrimidine acceptor core functionalized with one 3,6-bis(4,4'-dimethoxydiphenylamino)carbazole (3,6-CzDMPA) donor moiety via a phenyl π-spacer at the 3, 5 and 7 positions, respectively. The isolated compounds possess suitable energy levels, sufficient thermal stability (Td > 400 °C), molecular glass behavior with Tg values in the range of 127−136 °C slightly higher than that of the reference material Spiro-OMeTAD (126 °C) and acceptable hydrophobicity. Undoped PY1 demonstrates the highest hole mobility (3 × 10−6 cm2 V−1 s−1) compared to PY2 and PY3 (1.3 × 10−6 cm2 V−1 s−1). The whole isomers were incorporated as doped HTMs in planar n-i-p PSCs based on double cation perovskite FA0.85Cs0.15Pb(I0.85Br0.15)3. The non-optimized device fabricated using PY1 exhibited a power conversion efficiency (PCE) of 12.41%, similar to that obtained using the reference, Spiro-OMeTAD, which demonstrated a maximum PCE of 12.58% under the same conditions. The PY2 and PY3 materials demonstrated slightly lower performance in device configuration, with relatively moderate PCEs of 10.21% and 10.82%, respectively, and slight hysteresis behavior (−0.01 and 0.02). The preliminary stability testing of PSCs is also described. The PY1-based device exhibited better stability than the device using Spiro-OMeTAD, which could be related to its slightly superior hydrophobic character preventing water diffusion into the perovskite layer.

6-Nitro-2,3-dihydro-1H-pyrrolo-[2,1-c][1,4]benzodiazepine-5,11(10H,11aH)-dione.

In the two mol-ecules of the asymmetric unit of the title compound, C(12)H(11)N(3)O(4), the seven-membered diazepine ring adopts a boat conformation (with the two phenyl-ene C atoms representing the stern and the methine C atom the prow). The five-membered pyrrole ring, which has an envelope conformation, makes dihedral angles of 60.47 (10) and 54.69 (9)° with the benzene ring of the benzodiazepine unit in the two mol-ecules. In the crystal, inter-molecular N-H⋯O hydrogen bonds and π-π stacking inter-actions [centroid-centroid distance = 3.8023 (7)-3.8946 (7) Å] lead to the formation of a three-dimensional framework.

(Z)-6-Hy-droxy-1a,5-dimethyl-8-[(morpholin-4-yl)meth-yl]-2,3,6,7,7a,8,10a,10b-octa-hydro-oxireno[2',3':9,10]cyclo-deca-[1,2-b]furan-9(1aH)-one.

The title compound, C(19)H(29)NO(5), was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methylen-3,14-dioxatricyclo-[9.3.0.0(2),(4)]tetra-dec-7-en-13-one), which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The mol-ecule is built up from two fused five- and ten-membered rings with the (morpholin-4-yl)methyl group as a substituent. The five-membered lactone ring has an envelope conformation, whereas the ten-membered and the morpholine rings display approximate chair-chair and chair conformations, respectively. The dihedral angle between the ten-membered ring and the lactone ring is 27.93 (6)°. The crystal structure is stabilized by weak inter-molecular C-H⋯O hydrogen-bond inter-actions. An intra-molecular O-H⋯N hydrogen bond also occurs.

5,9-Dihy-droxy-9-methyl-3,6-dimethyl-ene-3a,4,5,6,6a,7,8,9,9a,9b-deca-hydro-azuleno[4,5-b]furan-2(3H)-one.

The title compound, C(15)H(20)O(4), was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methyl-ene-3,14-dioxatricyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The seven-membered ring has a chair conformation, while the five-membered rings display twisted conformations. The dihedral angle between the seven-membered ring and the lactone ring is 21.69 (10)°. In the crystal, mol-ecules are linked into chains propagating along the c axis by inter-molecular O-H⋯O hydrogen bonds; an intra-molecular O-H⋯O link also occurs.

10α-Hy-droxy-4,9-dimethyl-13-[(pyrrol-idin-1-yl)meth-yl]-3,8,15-trioxatetra-cyclo-[10.3.0.0.0]penta-decan-14-one.

The title compound, C(19)H(29)NO(5), was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methyl-ene-3,14-dioxatricyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The mol-ecule is built up from two fused five- and ten-membered rings with the (pyrrolidin-4-yl)methyl group as a substituent. The two five-membered ring display the same envelope conformations, whereas the ten-membered ring adopts an approximate chair-chair conformation. The dihedral angle between the ten-membered ring and the lactone ring is 21.81 (9)°. An intra-molecular O-H⋯N hydrogen bond stabilizes the mol-ecular conformation. In the crystal, inter-molecular C-H⋯O inter-actions link the mol-ecules into chains parallel to the c axis.