NaBH4/DOWEX(R)50WX4: A Convenient Reducing System for Fast and Efficient Reduction of Carbonyl Compounds to Their Corresponding Alcohols

The reduction of a variety of carbonyl compounds was efficiently carried out with NaBH₄/DOWEX(R)50WX4 system. The reactions were performed to give the corresponding alcohols derivatives in perfect yields in THF at room temperature. Reduction of acyloins and a‐diketones by this reducing system produced efficiently the corresponding vicinal diols. Also, the reduction of aldehydes over ketones has been accomplished successfully by this system. Regioselectivity of this system was also investigated with exclusive 1,2‐reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields.     

One-pot synthesis of 2H-indazolo[2,1-b]phthalazine-triones via nano γ-Al2O3/BF3/Fe3O4 as an efficient catalyst and theoretical DFT study on them

Experimental and computational studies were carried out for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones using γ-Al₂O₃/BF₃/Fe₃O₄ as a nanocatalyst in optimized and solvent-free conditions. The most significant features of the existing protocol are easy preparation of the catalyst, short reaction times, environmentally benign, and milder reaction conditions. The analysis data were reported using the experimental results of this investigation, such as: H-NMR, FT-IR (Fourier-transform infrared spectroscopy), X-ray diffraction, vibrating-sample magnetometer, Thermal gravimetric analysis (TG-DTG), nitrogen adsorption isotherm, Field Emission Scanning Electron Microscopy, and Transmission electron microscopy images of nanocatalyst. In this study, 2H-indazolo[2,1-b]phthalazine-triones have also been theoretically investigated using DFT-B3LYP/6-31G method. Also, some of the physical chemistry properties have examined for conformers of products, which there was good agreement between the computational results and obtained experimental for the products.     

Carboxyketenes from 4-hydroxy-1,3-oxazin-6-ones and Meldrum's acid derivatives

New 4-hydroxy-1,3-oxazin-6-ones 8 and 16 were prepared from chlorocarbonyl(phenyl)ketene and amides. The flash vacuum thermolysis (FVT) reactions of these compounds and the 4-methoxy derivative 17 were investigated by Ar matrix isolation IR spectroscopy and online mass spectrometry including MS/MS analysis. Carboxy(phenyl)ketene 10 is formed as the major product by thermal fragmentation of 4-hydroxy-1,3-oxazin-6-one 8. This takes place via the unstable 6-hydroxy tautomer 9. Another tautomer, the 5H-isomer 12, leads to the formation of benzoyl isocyanate 13 as a minor product together with phenylketene 14. Carboxy(phenyl)ketene 10 remains detectable at high FVT temperatures but undergoes thermal decarboxylation to phenylketene 14. The same carboxy(phenyl)ketene 10 is also produced in significant amounts by FVT of 5-phenyl-Meldrum's acid 18 via the unstable enol tautomer 19. A small amount of the unsubstituted carboxyketene 20 is observable on FVT of Meldrum's acid 1 itself.     

Chemical composition of the essential oil of Pelargonium quercetorum Agnew. of Iran

The volatile constituents in the essential oil of Pelargonium quercetorum Agnew., growing wild in Kurdistan, Iran were investigated through GC and GC/MS technique. Twenty-six compounds, representing 21 (80.77%) of the total oil were identified. The main components were: alpha-pinene (25.28%), alpha-fenchyl acetate (20.63%), limonene (9.94%), beta-caryophyllene (8.20%), camphene (4.31%), delta-cadinene (3.32%), beta-pinene (3.21%), alpha-amorphene (2.80%), valencene (2.73%), ledene (2.25%) and p-cymene (1.63%).     

Separation of anticancer medicines carmustine,lomustine, semustine and melphalan by PAMAM dendrimer: a theoretical study

Much progress has been made in the treatment of cancer. However, it remains a significant challenge to treat as toxic chemotherapeutic drugs are often poorly tolerated when administered together, limiting the patient’s treatment options. A possible solution to this problem is anchoring drugs on the surface of nanoparticles. These systems have a variety of structures with sizes, shapes and materials which determine loading capacity, cellular targeting and stability. Dendrimers are a class of nanoparticles which have been investigated in this context. In this study, we investigated the functionalization of polyamidoamine (PAMAM) dendrimers with some anticancer medications that suppresses the growth of cancer cells (carmustine, lomustine, semustine and melphalan; 1–4). The possibility of drug release, drug delivery and drug separation by PAMAM was theoretically investigated and discussed. The predicted theoretical method will be interesting to remove the pollutants from the medical solutions by PAMAM dendrimer nanoclusters. The results of the modeling were obtained by MMFF94 and RHF/PM6 methods for all form of the PAMAM–medicines complexes. The obtained results by these two methods were shown same trend of the relative energy surfaces of the complexes of PAMAM–medicines 1–4.     

Chemical composition analysis of the essential oil of Melissa officinalis L. from Kurdistan, Iran by HS/SPME method and calculation of the biophysicochemical coefficients of the components

The volatile constituents of the essential oil of wild Melissa officinalis L. obtained from the Kurdistan province of Iran were extracted by headspace/solid-phase micro-extraction and were analysed by gas chromatography and gas chromatography/mass spectrometry. Of a total of 14 compounds in the oil, 12 (85.7%) were identified. The main components were as follows: (E)-citral (37.2%), neral (23.9%) and citronellal (20.3%). Some physicochemical properties, such as the logarithm of calculated octanol-water partitioning coefficients (log?K (ow))(,) total biodegradation (TB (d) in mol?h(-1) and g?h(-1)), water solubility (S (w), mg?L(-1) at 25°C) and median lethal concentration 50 (LC(50)), were calculated for compounds 1-14 from M. officinalis L.     

Theoretical and Quantitative Structural Relationship Studies of Electrochemical Properties of the Nanostructures of Cis-Unsaturated Thiocrown Ethers and Their Supramolecular Complexes [X-UT-Y][M@C82] (M˭Ce,Gd)

The endohedral lanthanidofullerenes, an important type of organolanthanides, are stabilized by the delocalization of the negative charges on the cages of fullerenes. Since the discovery of these classes of carbon compounds and their unusual structures and properties of these molecules, many potential applications have been suggested. Unsaturated thiocrown ethers with cis-geometry are a group of crown ethers that, in light of the size of their cavities and their conformational restriction compared to a corresponding saturated system (1–9), demonstrate interesting properties for physicochemical studies. Endohedral lanthanidofullerenes M@C_x (x = 82 and M = Ce, Gd) were introduced as a new class of the spherical fullerene group with unique properties. Formation of endohedral metallofullerenes is thought to involve the transfer of electrons from the encapsulated metal atom(s) to the surrounding fullerene cage. Two of these molecules are the Ce@C₈₂ (10) and Gd@C₈₂ (11). The supramolecular complexes of 1–9 with Ce@C₈₂ (10) and Gd@C₈₂ (11) have been shown to possess a host–guest interaction for electron transfer processes, and these behaviors have previously been reported. Topological indices have been successfully used to construct effective and useful mathematical methods for finding good relationships between structural data and the various chemical and physical properties. To establish a good structural relationship between the structures of 1–9 and M@C_x that were introduced here, an index that is represented as μ_cs was utilized. This index is the ratio of summation of the number of carbon atoms (n_c ) and the number of sulfur atoms (n_s ) to the product of these two numbers for 1–9. In this study, the relationship between this index and oxidation potential ( ^oxE₁ ) of 1–9, as well as the free energy of electron transfer (ΔG_et , by the Rehm-Weller equation) between 1–9 and 10 and 11 as [X-UT-Y][Ce@C₈₂] (12) and [X-UT-Y][Gd@C₈₂] (13) complexes, is presented.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Theoretical study of 1,3-dipolar cycloaddition reactions between 7–10-membered simple cycloalkynes and triazoles R–N3 (R = H, CH3, Ph)

The energy contents in alkynes may be increased further by bending the normally linear triple bond, as in the small cycloalkynes. The strain energy in the cycloalkynes increases as the size of the ring decreases. Cycloadditions of 1,3-dipoles with alkynes occur by concerted mechanisms. In this study, the reactivity and strain energy effect of the cycloalkynes with substituted 1,2,3-triazoles R–N₃ (R = H, CH₃, and Ph) by the use of B3LYP/6-31G** level method will be discussed. The investigation of the structured properties, theoretical thermodynamic and kinetic data, i.e., ΔrG, ΔG* and rate constants of the reactions in 298 K will be presented.     

Application of a Sawdust/Fe3O4 and Sawdust/Fe3O4/PEI as a Selective Adsorbent for Pb(II) Removal

Based on the advantages of Fe₃O₄ nanoparticles (MNPs), sawdust (SD), and polyethlenimine (PEI) respectively, the SD/MNPs/PEI composites with layered structure were synthesized. The features of the nanocomposites were characterized and experimental conditions were used to evaluate the potential of SD/ MNPs and SD/MNPs/PEI nanocomposites in removing lead ions Pb2+ in a batch system. By cross-linking PEI on the SD/ MNPs, chelating group on the surface of adsorbent is made, which increases the ability of the nanocomposite to attract Pb(II) from aqueous solutions. Results show an increase in the adsorption by about 31% on SD/MNPs, by about 98% in SD/MNPs/PEI.