Synthesis and characterization of novel benzoxazine-based arylidinyl succinimide derivatives

<p>1,4-Benzoxazine skeleton holds substantial promise for further exploration owing to its immense pharmacological potential. In this pursuit, a series of 20 novel benzoxazine-based arylidinyl succinimide derivatives (<b>23</b>–<b>42</b>) were synthesized in moderate to good yields by the reaction of ethyl 2-(7-(2,5-dioxo-2,5-dihydro-1<i>H</i>-pyrrol-1-yl)-3-oxo-2<i>H</i>-benzo[<i>b</i>][1,4]oxazin-4(3<i>H</i>)-yl)acetate (<b>22</b>) with various aromatic aldehydes under Wittig reaction conditions in the presence of triphenylphosphine and ethanol. All these synthesized compounds were fully characterized from their spectral data (¹H, ¹³C, and ²D NMR, IR, UV, high-resolution mass spectroscopy (HRMS)) and further confirmed by X-ray crystallographic analysis of a representative compound (<b>32</b>). Antibacterial activity of obtained arylidinyl succinimide derivatives was evaluated against both Gram-positive and Gram-negative bacterial strains and were found to exhibit insignificant activity as compared to the reference.</p

Is Single-4-Ring the Most Basic but Elusive Secondary Building Unit That Transforms to Larger Structures in Zinc Phosphate Chemistry?

Haloaryl phosphates (X-dippH₂, X = Cl, Br, I) react with zinc acetate in the presence of collidine or 2-aminopyridine (2-apy) to yield zinc phosphate clusters [Zn­(X-dipp)­(collidine)]₄ (X = Cl (<b>1</b>), Br (<b>2</b>), I (<b>3</b>)) and [Zn­(X-dipp)­(2-apy)]₄·2MeOH (X = Cl (<b>4</b>), Br (<b>5</b>), I (<b>6</b>)), respectively. Single-crystal X-ray diffraction studies reveal that collidine and 2-apy capped zinc phosphates <b>1</b>–<b>6</b> exist as discrete tetrameric zinc phosphate molecules, exhibiting a cubane-shaped D4R core. In contrast, when the same reaction has been carried out in the presence of 4-cyanopyridine (4-CNpy), polymeric zinc phosphates {[Zn₄(X-dipp)₄(4-CNpy)₂(MeOH)₂]·2H₂O}_<i>n</i> (X = Cl (<b>7</b>), Br (<b>8</b>), I (<b>9</b>)) have been isolated. Compounds <b>7</b>–<b>9</b> are square-wave-shaped, one-dimensional polymers composed of fused S4R repeating units. The common structural motif found both in D4R cubanes <b>1</b>–<b>6</b> and polymers <b>7</b>–<b>9</b> is the S4R building block, which presumably undergoes further fusion because of the coordinative unsaturation at zinc and the simultaneous presence of free PO. The closed shell cubanes <b>1</b>–<b>6</b> are obviously formed by a <i>face-to-face</i> dimerization involving two S4R units in which the two PO groups are in cis-configuration. On the other hand, the one-dimensional (1-D) square-wave polymers <b>7</b>–<b>9</b> are formed from a face-to-face association of S4R building units in which the two PO groups are in a trans-configuration. In order to stabilize these elusive S4R zinc phosphates, the reaction between Cl-dippH₂ and zinc acetate was carried out in the presence of excess imidazole as an ancillary ligand (1:1:4), although only an imidazole decorated cubane cluster [Zn­(Cl-dipp)­(imz)]₄.2MeOH (<b>10</b>) was isolated. The chelating <i>N</i>,<i>N</i>′-donor 1,10-phenanthroline ligand was used to eventually isolate cyclic S4R phosphate [Zn­(μ₂-Cl-dipp)­(1,10-phen)­(OH₂)]₂·MeOH·H₂O (<b>11</b>). The change of Zn²⁺ source to zinc nitrate and the phosphate source to 2,6-dimethylphenyl phosphate (dmppH₂) led to the isolation of another polymeric phosphate [Zn­(dmpp)­(MeOH)]_<i>n</i> (<b>12</b>), with a zigzag backbone, formed through an <i>edge-to-edge</i> to polymerization of S4R building units with PO groups in trans-configuration. The isolation of four different structural types of zinc phosphates <b>A</b>–<b>D</b> in the present study can be rationalized in terms of fusion of S4R rings in a variety of ways to either produce discrete clusters or 1-D polymers

A Simple Approach to Prepare Carboxycellulose Nanofibers from Untreated Biomass

A simple approach was developed to prepare carboxycellulose nanofibers directly from untreated biomass using nitric acid or nitric acid-sodium nitrite mixtures. Experiments indicated that this approach greatly reduced the need for multichemicals, and offered significant benefits in lowering the consumption of water and electric energy, when compared with conventional multiple-step processes at bench scale (e.g., TEMPO oxidation). Additionally, the effluent produced by this approach could be efficaciously neutralized using base to produce nitrogen-rich salts as fertilizers. TEM measurements of resulting nanofibers from different biomasses, possessed dimensions in the range of 190–370 and 4–5 nm, having PDI = 0.29–0.38. These nanofibers exhibited lower crystallinity than untreated jute fibers as determined by TEM diffraction, WAXD and ¹³C CPMAS NMR (e.g., WAXD crystallinity index was ∼35% for nanofibers vs 62% for jute). Nanofibers with low crystallinity were found to be effective for removal of heavy metal ions for drinking water purification

Efficient Removal of UO₂²⁺ from Water Using Carboxycellulose Nanofibers Prepared by the Nitro-Oxidation Method

Carboxycellulose nanofibers (NOCNF) were extracted from untreated jute fibers using a simple nitro-oxidation method, employing nitric acid and sodium nitrite. The resulting NOCNF possessed high surface charge (−70 mV) and large carboxylate content (1.15 mmol/g), allowing them to be used as an effective medium to remove UO₂²⁺ ions from water. The UO₂²⁺ (or U­(VI)) removal mechanism was found to include two stages: the initial stage of ionic adsorption on the NOCNF surface following by the later stage of uranyl hydroxide mineralization, as evidenced by the Fourier transform infrared, scanning electron microscopy with energy dispersive spectroscopy capabilities, transmission electron miscroscopy, and wide-angle X-ray diffraction results. Using the Langmuir isotherm model, the extracted NOCNF exhibited a very high maximum adsorption capacity (1470 mg/g), about several times higher than the most efficient adsorbent reported (poly­(acrylic acid) hydrogel). It was also found that the remediation of UO₂²⁺ ions by NOCNF was pH dependent and possessed the maximum adsorption at pH = 7. The removal efficiency of NOCNF was between 80 and 87% when the UO₂²⁺ concentration was below 1000 ppm, while it decreased to 60% when the UO₂²⁺ concentration was around 1250 ppm

An Expedient Route to Imidazo[1,4]diazepin-7-ones via A Post-Ugi Gold-Catalyzed Heteroannulation

A novel diversity-oriented post-Ugi/gold(I)-catalyzed heteroannulation process for the synthesis of imidazo[1,4]diazepin-7-ones is elaborated. The scope and limitations of the protocol are discussed

Role of the bradykinin B2 receptor in a rat model of local heart irradiation

<div><p></p><p><i>Purpose</i>: Radiation-induced heart disease (RIHD) is a delayed effect of radiotherapy for cancers of the chest, such as breast, esophageal, and lung. Kinins are small peptides with cardioprotective properties. We previously used a rat model that lacks the precursor kininogen to demonstrate that kinins are involved in RIHD. Here, we examined the role of the kinin B2 receptor (B2R) in early radiation-induced signaling in the heart.</p><p><i>Materials and methods</i>: Male Brown Norway rats received the B2R-selective antagonist HOE-140 (icatibant) via osmotic minipump from 5 days before until 4 weeks after 21 Gy local heart irradiation. At 4 weeks, signaling events were measured in left ventricular homogenates and nuclear extracts using western blotting and real-time polymerase chain reaction. Numbers of CD68<b>-</b>positive (monocytes/macrophages), CD2<b>-</b>positive (T-lymphocytes), and mast cells were measured using immunohistochemistry.</p><p><i>Results</i>: Radiation-induced c-Jun phosphorylation and nuclear translocation were enhanced by HOE-140. HOE-140 did not modify endothelial nitric oxide synthase (eNOS) phosphorylation or alter numbers of CD2-positive or mast cells, but enhanced CD68-positive cell counts in irradiated hearts.</p><p><i>Conclusions</i>: B2R signaling may regulate monocyte/macrophage infiltration and c-Jun signals in the irradiated heart. Although eNOS is a main target for kinins, the B2R may not regulate eNOS phosphorylation in response to radiation.</p></div

<i>In Vivo</i> Efficacy of a Synthetic Coumarin Derivative in a Murine Model of Aspergillosis

<div><p>Despite advances in therapeutic modalities, aspergillosis remains a leading cause of mortality. This has necessitated the identification of effective and safe antifungal molecules. In the present study, <i>in vivo</i> safety and antifungal efficacy of a coumarin derivative, <i>N</i>, <i>N, N</i>-Triethyl-11-(4-methyl-2-oxo-2<i>H</i>-benzopyran-7-yloxy)-11-oxoundecan-1-aminium bromide (SCD-1), was investigated. The maximum tolerable dose of compound was determined according to OECD 423 guidelines. The compound could be assigned to category IV of the Globally Harmonized System and its LD₅₀ cut-off was found to be 2000 mg/kg body weight. The survival increased in <i>Aspergillus fumigatus-</i>infected mice treated with a dose of 200 mg/kg, orally or 100 mg/kg body weight, intraperitoneally, of SCD-1 in comparison to infected-untreated animals. The SCD-1 treatment resulted in significant reduction in colony counts in vital organs of the animals. Its protective effect was also observed on day 14 as there was marked reduction in fungal colonies. The treatment with SCD-1 also reduced the levels of serum biochemical parameters with respect to infected-untreated animals. It could be concluded that SCD-1 is a quite safe antifungal compound, which conferred dose dependent protection against experimental aspergillosis. Therefore, SCD-1 holds potential for developing new formulations for aspergillosis.</p></div

Body weights of experimental mice.

<p>The daily weight (Mean ± SE) of animals belonging to different groups was recorded daily over a period of 14 days.</p

Survival rate in experimental mice.

<p>The animals were challenged intranasally with conidia of <i>A. fumigatus</i> and treated with different doses of SCD-1, daily, upto 14 days.</p

Fungal burden in different organs of experimental animals.

<p>The number of CFUs (Mean ± SE) were determined on 7^th (A) and 14^th (B) day of infection. Asterisks indicate statistically significant differences. *<i>p</i><0.05, **<i>p</i><0.001.</p