Chloroacetophenone Research Articles

Molecular modelling and antimicrobial activity of newly synthesized benzothiazolo[3,2-a]pyrimidine clubbed thiazole derivatives

A series of benzothiazolopyrimidine-thiazole conjugates 7, 8, and 9 were produced through the reactions of 8-acetylbenzothiazolopyrimidine-thiosemicarbazone compound 6 with chloroacetone, (un)substituted phenacyl chlorides, and ethyl chloroacetate, respectively. Based on DFT study, the synthesized conjugates had a twisted shape, except for the parent benzothiazolopyrimidine 5 and its thiosemicarbazone compound 6, which were flat. The study of FMO's also showed that the substituted thiazole derivatives 7 and 8a-c have equivalent configurations of HOMO and LUMO, as well as exhibiting the least FMO's gap (ΔEH-L). The antimicrobic activeness of the constructed derivatives has been assessed against the two Gram's types of bacteria and fungi using the broth microdilution method. The benzothiazolopyrimidine-thiazole conjugate 8c exhibited the strongest inhibition towards Gram-negative E. coli (MIC <29 μg/mL), while a valuable performance was observed towards S. typhimurium (MIC <132 μg/mL). Also, it displayed broad-spectrum activity with the least MIC versus C. albicans fungi (<207 μg/mL). In contrast, the conjugate 8b demonstrated selective efficacy against Gram + ve S. aureus and B. subtilis bacteria (MIC <40 and < 47 μg/mL, respectively). Besides, molecular docking of these benzothiazolopyrimidine derivatives with the PDB: 2XCT protein carried out to discover their binding types, RMSD, binding scores, and interactions pocket for each derivative, including a drug reference. Furthermore, their physicochemical-pharmacokinetic profile has estimated via the SwissADME prediction. The data indicated that derivative 5 demonstrated constructive pharmacokinetics (M. Wt. 269.28), lipophilicity (Log Po/w = 1.45), and TPSA = 103.47, which foretold high (GI) absorption and good bioavailability = 0.55 without interrupting Lipinski's rules.

Imidazolidine‐pyrroloimidazolone Pyridine‐Ni(acac)2 complex Catalyzed Asymmetric Darzens Reaction of Isatins with Phenacyl Chlorides: A Chiral Amplification Effect

With phenacyl chlorides as simple nucleophilic species, the asymmetric Darzens reaction of isatins using Ni(acac)2 as the Lewis acid and imidazolidine‐pyrroloimidazolone pyridine as the ligand is reported. In the presence of 1 mol% of catalyst, diverse spiro‐epoxyoxindoles with two new contiguous stereocenters were afforded in 82‐99% yields, &gt;20:1 dr, and 91‐99% ee. Chiral spiro‐epoxyoxindoles could undergo ring‐opening reactions in further transformations. The developed method was applied to the derivatization of complex molecules including indomethacin, gemfibrozil, and febuxostat‐derived α‐chloroketones. A strong positive nonlinear effect was observed, which was caused by the precipitation of a less‐soluble racemic catalyst complex.

Thiadiazole/Thiadiazine Derivatives as Insecticidal Agent: Design, Synthesis, and Biological Assessment of 1,3,4-(Thiadiazine/Thiadiazole)-Benzenesulfonamide Derivatives as IGRs Analogues against Spodoptera littoralis.

In keeping with our investigation, a simple and practical synthesis of novel heterocyclic compounds with a sulfamoyl moiety that can be employed as insecticidal agents was reported. The compound 2-hydrazinyl-N-(4-sulfamoylphenyl)-2-thioxoacetamide 1 was coupled smoothly with triethylorthoformate or a variety of halo compounds, namely phenacyl chloride, chloroacetyl chloride, chloroacetaldehyde, chloroacetone, 1,3-dichloropropane, 1,2-dichloroethane, ethyl chloroformate, 2,3-dichloro-1,4-naphthoquinone, and chloroanil respectively, which afforded the 1,3,4-thiadiazole and 1,3,4-thiadiazine derivatives. The new products structure was determined using elemental and spectral analysis. Under laboratory conditions, the biological and toxicological effects of the synthetic compounds were also evaluated as insecticides against Spodoptera littoralis (Boisd.). Compounds 3 and 5 had LC50 values of 6.42 and 6.90 mg/L, respectively. The investigated compounds (from 2 to 11) had been undergoing molecular docking investigation for prediction of the optimal arrangement and strength of binding between the ligand (herein, the investigated compounds (from 2 to 11)) and a receptor (herein, the 2CH5) molecule. The binding affinity within docking score (S, kcal/mol) ranged between -8.23 (for compound 5), -8.12 (for compound 3) and -8.03 (for compound 9) to -6.01 (for compound 8). These compounds were shown to have a variety of binding interactions within the 2CH5 active site, as evidenced by protein-ligand docking configurations. This study gives evidence that those compounds have 2CH5-inhibitory capabilities and hence may be used for 2CH5-targeting development. Furthermore, the three top-ranked compounds (5, 3, and 9) and the standard buprofezin were subjected to density functional theory (DFT) analysis. The highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy difference (ΔE) of compounds 5, 3, and 9 was found to be comparable to that of buprofezin. These findings highlighted the potential and relevance of charge transfer at the molecular level.

Palomar discovery and initial characterization of naked-eye long-period comet C/2022 E3 (ZTF)

ABSTRACT Long-period comets are planetesimal remnants constraining the environment and volatiles of the protoplanetary disc. We report the discovery of hyperbolic long-period comet C/2022 E3 Zwicky Transient Facility (ZTF), which has a perihelion ∼1.11 au, an eccentricity ≳1 and an inclination ∼109°, from images taken with the Palomar 48-inch telescope during morning twilight on 2022 March 2. Additionally, we report the characterization of C/2022 E3 (ZTF) from observations taken with the Palomar 200-inch, the Palomar 60-inch, and the NASA Infrared Telescope Facility in early 2023 February to 2023 March when the comet passed within ∼0.28 au of the Earth and reached a visible magnitude of ∼5. We measure g–r = 0.70 ± 0.01, r–i = 0.20 ± 0.01, i–z = 0.06 ± 0.01, z–J = 0.90 ± 0.01, J–H = 0.38 ± 0.01, and H–K = 0.15 ± 0.01 colours for the comet from observations. We measure the A(0°)fρ (0.8 μm) in a 6500 km radius from the nucleus of 1483 ± 40 cm, and CN, C3, and C2 production of 5.43 ± 0.11 × 1025, 2.01 ± 0.04 × 1024, and 3.08 ± 0.5 × 1025 mol s−1, similar to other long-period comets. We additionally observe the appearance of jet-like structures at a scale of ∼4000 km in wide-field g-band images, which may be caused by the presence of CN gas in the near-nucleus coma.

New thieno[2,3-b]pyridine-based compounds: Synthesis, molecular modelling, antibacterial and antifungal activities

New thieno[2,3-b]pyridine clubbed various thiazole ring systems were synthesized by the reaction of 2-(1-(3-amino-4,6-dimethylthieno[2,3-b]pyridin-2-yl)ethylidene)hydrazine-1-carbothioamide with chloroacetone, phenacyl chloride, and chloroacetic acid. The molecular modeling of the synthesized compounds using DFT/B3LYP methodology revealed that all have a low HOMO and LUMO energies, −4.85 - −5.52 and −2.79 - −3.62, respectively, where the compound 10 has the highest values. The targeting thienopyridine analogues with various thiazole moieties 3–10 was assessed in order to create new antimicrobial agents and compared with ampicillin, gentamicin and miconazole as reference antibacterial and antifungal drugs. Compounds 8–10 exhibited potent antimicrobial activity against Gram positive S. aureus, Gram Gram negative E. coli bacteria, and C. albicans (antifungal), with IC50 (18.9 ± 0.63––24.3 ± 0.74 µg/mL), (14.2 ± 0.41––19.5 ± 0.64 µg/mL), and (19.2 ± 0.58–––23.4 ± 0.65 µg/mL), respectively. Furthermore, Molecular docking stimulation on MOE program was applied to expect the effect and interactions of the newly thienopyridine analogues and E. coli DNA gyrase B as it expressed by PDB ID: 1AJ6.

Analysis of CN Coma Morphology Features of Comet 21P/Giacobini–Zinner

We analyze jet features found in the coma of comet 21P/Giacobini–Zinner (21P/GZ) during its 2018 perihelion passage using narrowband CN photometric imaging in order to determine the comet’s rotational period, and we constrain the CN gas outflow velocity and rotational state through the analysis of azimuthally enhanced morphological features. We find that 21P/GZ has a period of either 7.39 ± 0.01 hr or 10.66 ± 0.01 hr. We measure a lower limit to the outflow velocity for the northern jet of 730 ± 30 m s−1 and for the southern jet of 740 ± 30 m s−1. We analyze the morphologies of the jet features and determine that the northern jet possesses a corkscrew pattern, and we utilize that knowledge to determine a rotational pole position at an R.A. of deg and a decl. of deg, with an undetermined sense of rotation.

Synthesis and Anticancer Evaluation of New Thiazole and Thiadiazole Derivatives Bearing Acetanilide Moiety.

New thiazole and thiadiazole derivatives bound to the acetanilide moiety were synthesized and evaluated for their cytotoxic activity. The precursor N-(4-acetamidophenyl)-N'-phenylthiourea (2) was cyclocondensed with ethyl bromoacetate to afford a mixture of the two isomers, 2-(4-acetamidophenylimino)-3-phenylthiazolidin-4-one (3a, 23%) and 3-(4-acetamidophenyl)-2-phenyliminothiazolidin-4-one (3b, 71%). The Knoevenagel reaction of 3b with various aromatic aldehydes afforded 5-arylidene-2-phenyliminothiazolidin-4-one derivatives 5a-5e. Intramolecular cyclization of thiourea scaffold 2 with chloroacetone and/or phenacyl chloride gave the conforming thiazole derivatives 6a and 6b. A new series of thiadiazole derivatives 9a-9c and 11a-11c was synthesized by the reaction of N-(4-acetamidophenyl)-N'-phenylthiourea (2) with selected derivatives of hydrazonoyl halide in ethanol and triethylamine. The structures of the synthesized thiazole and thiadiazole compounds were elucidated by their compatible spectral data. The cytotoxic activity of the synthesized thiazole and thiadiazole derivatives was screened against four human cancer cell lines and showed promising results. Thiazolidin-4-one compound 5d showed the strongest cytotoxic effects on hepatocellular carcinoma (IC50 = 8.80 ± 0.31 μg/mL), mammary gland breast cancer (IC50 = 7.22 ± 0.65 μg/mL) and colorectal carcinoma (IC50 = 9.35 ± 0.61 μg/mL) cell lines.

Nucleophile-Controlled Halide Release from the Substitution Reaction of Haloketone for Facet Tuning and Manganese Doping in CsPbCl3 Nanocrystals.

Halide content of the reaction medium not only enhances the brightness of CsPbCl3 nanocrystals but also, control the shape modulations as well as doping Mn(II) in these host nanocrystals. Correlating both the shape effect and doping, herein, an in situ reaction of nucleophile-controlled halide release was explored for monitoring facets modulations and doping in CsPbCl3 nanocrystals. This was performed using alkyl amine as nucleophile which reacted with α-halo ketone, phenacyl chloride, to release chloride ions. Increase in amine concentration which released more Cl ions, reduced the possibility of shape transformation from perfect to truncated cubes during annealing. Similarly, for Mn(II) doping, the dopant photoluminescence intensity remained directly proportional to the amount of introduced amine nucleophiles. Quality of both doped and undoped nanocrystals obtained in this procedure remained unparallel and the method provided a strong correlation of rate of halide release with both facet modulations and doping in these nanocrystals.

Molecular modeling and antioxidant activity of newly synthesized 3‑hydroxy-2-substituted-thiophene derivatives

A facile synthesis of 3‑hydroxy-4-(4-hydroxyphenylazo)thiophenes with various functional groups at position-2 of thiophene ring and their corresponding O-acetylated products is described. The synthetic strategy is based on cyclization of the precursor ethyl 2-(2-(4-hydroxyphenyl)hydrazono)-3-(phenylamino)-3-thioxopropanoate with the appropriate α-chlorinated reagents (namely; chloroacetone, phenacyl chloride, ethyl chloroacetate and chloroacetonitrile). The produced 3‑hydroxy-4-(4-hydroxyphenylazo)thiophenes were acetylated upon heating in acetic anhydride to yield the corresponding 3‑hydroxy-4-(4-acetoxyphenylazo)thiophenes and/or 3-acetoxy-4-(4-acetoxyphenylazo)thiophenes. The synthesized thiophene derivatives were characterized by IR, 1H NMR and mass spectroscopic analyses. The DFT modeling of the synthesized derivatives offered a reasonable description about why the acetylation reaction was occurred on the phenolic OH group rather than the OH group at position-3 of thiophene ring. While in case of 2-cyano-3‑hydroxy-4-(4-hydroxyphenylazo)-5-(phenylamino)-thiophene, both hydroxyl groups were acetylated. The antioxidant activities for the synthesized compounds were assessed through DPPH technique. The 3-hydroxythiophene derivatives 5a-c displayed significant activity with IC50 values (3.01–26.27 µg/mL) using BHA, BHT and ascorbic acid as reference antioxidants. Meanwhile, the results of molecular docking study that applied on the synthesized thiophene derivatives supported the experimental antioxidant assay.

Synthesis, Molecular Modeling, and Anticancer Screening of Some New Imidazothiadiazole Analogs

A series of N-aryl-2-((6-arylimidazo[2,1-b]thiadiazol-2-yl)thio)acetamide compounds 4 and 5 was synthesized by heterocyclization of their precursors N-aryl-2-((5-amino-1,3,4-thiadiazol-2-yl)thio)acetamides 3a–c with phenacyl chloride reagents. The structural and spectral features of the synthesized compounds were studied using DFT calculations. The DFT-estimated 1H NMR spectral data exhibited good agreement with the experimental data. Furthermore, the HOMO–LUMO energies were used in determination of some chemical reactivity descriptors. The cytotoxic activities of the prepared imidazothiadiazoles were evaluated toward four different cancer cell lines. Derivatives 5c, 4c, 5a, and 4a presented powerful cytotoxic results against breast cancer rather than the residual derivatives 5b and 4b compared with 5-fluorouracil as a reference. Meantime, the docking study was used on the synthesized imidazothiadiazole analogs and furnished adequate results toward PDB ID: 1DLS.

Synthesis and Antibacterial Activity of New Imidazo[1,2-a]pyridines Festooned with Pyridine, Thiazole or Pyrazole Moiety

A series of new 6,8-dichloro-imidazo[1,2-a]pyridine derivatives incorporating pyridine, thiazole, and pyrazole ring systems was synthesized. The synthetic strategy of imidazopyridinyl-pyridine hybrids 2 and 3 involves one pot reaction of the precursor 3-acetyl-6,8-dichloro-2-methylimidazo[1,2-a] pyridine (1) with aldehydes, malononitrile, and/or ethyl cyanoacetate. Treatment of 1 with thiosemicarbazide and/or bromine followed by subsequent cyclization with ethyl bromoacetate, chloroacetone, phenacyl chloride, and/or thiourea was applied as synthetic routes for accessing the imidazopyridinyl-thiazole hybrids 5, 6, and 8–10. The reaction of 1 with dimethylformamide-dimethylacetal followed by subsequent treatment with hydrazine was employed to prepare the imidazopyridinyl-pyrazole motif 12. The antibacterial potency of these imidazopyridine hybrids has been evaluated against some model bacteria. The results indicated that the imidazopyridine-thiazole hybrids revealed remarkable antibacterial activities.

Visible and near-infrared observations of interstellar comet 2I/Borisov with the 10.4-m GTC and the 3.6-m TNG telescopes

ABSTRACTIn this work, we present the results of an observational study of 2I/Borisov carried out with the 10.4-m Gran Telescopio Canarias (GTC) and the 3.6-m Telescopio Nazionale Galileo (TNG), both telescopes located at the Roque de Los Muchachos Observatory, in the island of La Palma (Spain). The study includes images in the visible and near-infrared, as well as visible spectra in the 3600–9200 Å wavelength range. N-body simulations were also performed to explore its orbital evolution and Galactic kinematic context. The comet’s dust continuum and near-infrared colours are compatible with those observed for Solar system comets. From its visible spectrum on the nights of 2019 September 24 and 26, we measured CN gas production rates Q(CN) = (2.3 ± 0.4) × 1024 mol s−1 and Q(CN) = (9.5 ± 0.2) × 1024 mol s−1, respectively, in agreement with measurements reported by other authors on similar nights. We also obtained an upper limit for the C2 production rate of Q(C2) &amp;lt; (4.5 ± 0.1) × 1024 mol s−1. Dust modelling results indicate a moderate dust production rate of ∼50 kg s−1 at heliocentric distance rh = 2.6 au, with a differential power-law dust size distribution of index ∼–3.4, within the range reported for many comet comae. Our simulations show that the Galactic velocity of 2I/Borisov matches well that of known stars in the solar neighbourhood and also those of more distant regions of the Galactic disc.

Sintesis 2’-Hidroksi-5’-Kloro-3,5-Dimetoksi-4-Hidroksikalkon

Chalcone are compounds that have 2 aromatic rings connected by 3 carbon atoms which are an ?, ? unsaturated carbonyl system that have various biological activities. 2'-hydroxy-5'-chloro-3,5-dimethoxy-4-hydroxicalcone was synthesized from 2'-hydroxy-5'-chloro acetophenone and syringaldehyde using a NaOH catalyst. This compound was purified using Column Chromatography by isocratic method using n-hexane:ethyl acetate (15:1) as eluent. This compound has a Rf 0.75 and 2.7% of yield.

Synthesis and antioxidant assay of new nicotinonitrile analogues clubbed thiazole, pyrazole and/or pyridine ring systems

AbstractA series of novel nicotinonitrile derivatives were synthesized by hybridization with thiazole, pyrazole, and pyridine ring systems using 4‐aminobenzohydrazide as link‐bridge. The synthetic strategy of nicotinonitrile‐thiazole analogues involves cyclization of the precursor N‐phenyl thiosemicarbazide derivative 4 with chloroacetic acid and phenacyl bromide. The reaction of hydrazide 3 with acetylacetone and/or ethyl acetoacetate was applied as a synthetic route for accessing 2‐((4‐(pyrazole‐1‐carbonyl)phenyl)amino)‐nicotinonitrile derivatives 9–10. The 2‐((4‐(4‐thiazolylidene‐pyrazole‐1‐carbonyl)‐phenyl)amino)nicotinonitriles 14–15 were obtained via a nucleophilic addition of pyrazolone 10 to phenyl isothiocyanate followed by cyclization with chloroacetone, phenacyl chloride, and/or ethyl bromoacetate. The 6‐amino‐4‐aryl‐3,5‐dicyano‐2‐oxo‐1‐(4‐substitutedbenzamido)‐pyridines 19 were synthesized by Knoevenagel condensation N′‐(2‐cyanoacetyl)‐benzohydrazide derivative 16 with substituted benzaldehydes followed by heating with malononitrile. All synthesized products were evaluated for their antioxidant potentialities using of 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) radical cation delcolorization assay. The nicotinonitrile‐thiazole hybrid 6b was found the most promising antioxidant agent with inhibition activity 86.27%.

Decomposition products and formation path of C3F7CN/CO2 mixture with suspended discharge

A mixture of perfluoronitrile (C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> CN) and carbon dioxide (CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) has excellent insulation and environmental protection properties, and it is considered to have the potential to replace SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> gas. However, there are few studies on the decomposition products and formation reasons of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> CN/CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas under partial discharge. In order to study the decomposition characteristics of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> CN/CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas, suspension potential was used to simulate partial discharge. The experimental study on partial discharge decomposition of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> CN/CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas was carried out. The variation of decomposition products with discharge time was qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry (GC/MS). The results show that the decomposition products of suspension discharge of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> CN/CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> are mainly CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> , C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sub> , CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> CN and an unknown product. The relative contents of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> remain basically unchanged with the increase of discharge time. The relative contents of CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> , C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sub> and unknown products show a non-linear growth trend with the increase of discharge time. The relative content of CF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> CN gas shows a saturation trend with the increase of discharge time. Finally, based on density functional theory (DFT), the formation paths of various products are analyzed.

Stereoselective cyclopropanation of olefins through ammonium ylides: A molecular electron density theory study

AbstractThe highly trans stereoselective formation of cyclopropane derivative trans‐CP 6 via the reaction of ammonium salt (AS 2) with methyl vinyl ketone (MVK) in the presence of Na2CO3 was theoretically investigated within Molecular Electron Density Theory (MEDT) at the B3LYP/6‐31G(d) computational level to probe energetics, selectivities, and molecular mechanism. This domino reaction starts by nucleophilic substitution reaction between 1,4‐diazabicyclo[2.2.2]octane (DABCO) and phenacyl chloride (PC) to form AS 2 followed by a proton abstraction from AS 2 in the presence of Na2CO3 to yield ammonim ylide (AY 3). Subsequently, AY 3 nucleophilically attacks to the MVK to produce gauche betaine‐like intermediate IN‐Tg 2, which is converted into anti betaine‐like intermediate IN‐Ta through a C–C single bond rotation. Finally, trans‐CP 6 is generated along a ring‐closure step. Analysis of the relative Gibbs free energies shows that nucleophilic attack of AY 3 to MVK is the rate‐determining step (RDS). An analysis of the density functional theory (DFT)‐based reactivity indices permits that AY 3 and MVK are, respectively, classified as a strong nucleophile and as a strong electrophile, in clear agreement with the high polar character of the additional step while exploring of the electrophilic as well as nucleophilic Parr functions computed at the reactive sites of reagents elucidates the regioselectivity within the C1–C4 single bond formation process.

The REASONS Survey: Resolved Millimeter Observations of a Large Debris Disk around the Nearby F Star HD 170773

Abstract Debris disks are extrasolar analogs to our own Kuiper Belt and they are detected around at least 17% of nearby Sun-like stars. The morphology and dynamics of a disk encode information about its history, as well as that of any exoplanets within the system. We used the Atacama Large Millimeter/submillimeter Array (ALMA) to obtain 1.3 mm observations of the debris disk around the nearby F5V star HD 170773. We image the face-on ring and determine its fundamental parameters by forward-modeling the interferometric visibilities through a Markov Chain Monte Carlo approach. Using a symmetric Gaussian surface density profile, we find a 71 ± 4 au wide belt with a radius of au, a relatively large radius compared with most other millimeter-resolved belts around late A/early F type stars. This makes HD 170773 part of a group of four disks around A and F stars with radii larger than expected from the recently reported planetesimal belt radius—stellar luminosity relation. Two of these systems are known to host directly imaged giant planets, which may point to a connection between large belts and the presence of long-period giant planets. We also set upper limits on the presence of CO and CN gas in the system, which imply that the exocomets that constitute this belt have CO and HCN ice mass fractions of &lt;77% and &lt;3%, respectively. This is consistent with solar system comets and other exocometary belts.

Deep Eutectic Solvent Mediated One-Pot Synthesis of Hydrazinyl-4-Phenyl-1,3-Thiazoles

One-pot synthesis of hydrazinyl-4-phenyl-1,3-thiazole derivatives was developed by three-component reaction of various ketones or aldehydes, phenacyl chloride, and thiosemicarbazid in the presence of choline chloride/urea as a deep eutectic solvent (DES) at 70 °C. The products formed in excellent yields over short reaction times under an environmentally friendly condition. This method develops by using an environmentally benign synthetic method along with the use of a cost-effective catalyst. The study of antibacterial activity revealed that the compounds (4j, 4k, 4l, 4m, 4s, and 4t) showed good inhibition toward Escherichia coli.

Synthesis and Antioxidant Activity of Some Novel Nicotinonitrile Derivatives Bearing a Furan Moiety

As a part of ongoing studies in developing new potent antioxidant agents, 2‐amino‐4‐(furan‐2‐yl)‐5,6‐dimethylnicotinonitrile 4 was utilized as a key intermediate for the synthesis of some new pyrimidines 5 and 11, form (acet)amide 6, 7, urea and thiourea 9, 10, 1,8‐naphthyridines 12, 13, and 14. Moreover, condensation of 4 with 5,5‐dimethyl‐1,3‐cyclohexanedione and cyclohexanone in ethanol furnished the pyridine derivatives 16 and 17, respectively. Furthermore, refluxing of 4 with ethylenediamine in carbon disulfide afforded the 4,5‐dihydro‐1H‐imidazol‐2‐yl pyridine derivative 19. In addition, refluxing of 4 with carbon disulfide and concentrated sulfuric acid furnished the pyridine derivatives 20 and 21, respectively. The reaction of 4 with phenacyl chloride and ethyl chloroacetate in dimethylformamide in the presence of catalytic amount of triethylamine afforded the pyridine derivatives 22 and 23, respectively. Finally, heating of 4 with 1‐phenyl‐3‐(piperidin‐1‐yl)propan‐1‐one hydrochloride in glacial acetic acid afforded phenylpropylamino pyridine derivative 24. The structures of the newly synthesized compounds were confirmed by elemental analysis, IR, 1H‐NMR, and mass spectral data. Representative compounds of the synthesized products were evaluated as antioxidant agents. Compounds 8, 19, and 22 are promising compounds.

A comparative study of performance and regulated emissions in a medium-duty diesel engine fueled with sugarcane diesel-farnesane and sugarcane biodiesel-LS9

Two sugarcane biofuels and mineral diesel fuel are tested under full load conditions, under the same values of performance and under the European Transient Cycle on an engine test bench, without any modifications to the ECU. The target is to compare engine performance and emissions. At full load, engine performance varies due to the variation in LHV. Under the same values of performance, the sugarcane biodiesel-LS9 provides the lowest THC emissions. The higher CN and exhaust gas recirculation of the sugarcane biodiesel-LS9 and the higher H/C ratio of the sugarcane diesel-farnesane compared to the diesel S50 provide a NOx reduction. Neither the increment in bsfc nor the increment of %EGR for the sugarcane biodiesel-LS9 deteriorate the combustion, so its CO emissions are lower. The sugarcane biodiesel-LS9 leads to the lowest NOx and PM specific emissions under transient operation, followed by the sugarcane diesel-farnesane. The THC and CO specific emissions are higher for the biofuels in comparison to the diesel S50. The main reason for these results is the impact of the properties of the biofuels on the ECU response However, both biofuels produce less harmful emissions at idle conditions, which supports their usage to reduce exhaust emissions in urban areas.