EtOAc-dispersed magnetic nanoparticles (DMNPs) of γ-Fe2O3 in the single-pot domino preparation of 5-oxo-2-thioxo-3-thiophenecarboxylate derivatives

EtOAc-dispersed magnetic nanoparticles (DMNPs) of γ-Fe₂O₃ represent a straightforward and green catalyst for the rapid three-component synthesis of 5-oxo-2-thioxo-3-thiophenecarboxylate derivatives as rhodanine skeletons via a single-pot domino process. The rhodanines were prepared over magnetic nanoparticles of γ-Fe₂O₃ without any salt or additives. Dispersed nano-γ-Fe₂O₃ have many advantages, such as stability in air, reusability, reactions with high efficiency, simple separation with magnetic external field from mixture reactions, chemical stability, and also low toxicity.     

Novel Approach for the Synthesis of N-Substituted-4-(2-methyl-4-oxo-4H-quinazolin-3-yl)-butyramides

A simple and convenient method for the synthesis of N-substituted-4-(2-methyl-4-oxo-4H-quinazolin-3-yl)-butyramides has been reported. Several aromatic and aliphatic amide derivatives of 4-(2-methyl-4-oxo-4H-quinazolin-3-yl)-butyric acid were prepared in 60–81% yields by refluxing it with different phosphazo compounds in toluene for approximately 1 h.     

Reactivity of Various α-Halo Ketones in One-Pot Synthesis of γ-Iminolactones

The highly reactive 1:1 intermediate generated in the reaction of tert-butyl isocyanide and dialkyl acetylenedicarboxylate is trapped by α-halo ketones to produce halogenated iminolactones as the sole product in good yields.     

Combination of Novozym 435–Catalyzed Hydrolysis and Mitsunobu Reaction for Production of (R)-γ-Lactones

Chiral γ-lactones of both enantiomers were synthesized with more than 90% optical purities. The key step was Novozym 435–catalyzed hydrolysis of racemic N-benzyl-4-acetoxyalkylamides. Additionally, because (R)-γ-lactones are predominant in apricot, mango, peach, passion fruit, and strawberry, synthesis was attempted using only one enantiomer selectively. The (R)-enantimer was synthesized with more than 80% total yield and more than 90% optical purity by a combination of Novozym 435–catalyzed hydrolysis and the Mitsunobu reaction.     

THE STEREOSELECTIVE SYNTHESIS OF N-ARYL-TRANS,TRANS-α-CARBOXYL-β-METHOXYCARBONYL-γ-ARYL-γ-BUTYROLACTAMS

Cis-1-methoxycarbonyl-2-aryl-6,6-dimethyl-5,7-diox-spiro-[2,5]-4,8-octadiones (1) in dimethyl ethylene glycol at room temperature react with anilines (2) to give N-aryl-trans,trans-α-carboxyl-β-methoxycarbonyl-γ-aryl-γ-butyrolactams (3) in good to excellent yields and high stereoselectivity.     

Stereoselective Synthesis and Characterization of (Z)-(−)-4-(1′-Alkoxyl-1′-alkyloxycarbonyl-methylidene)-5(R)-[(1R)-menthyloxy]-γ-butyrolactones

Abstract

A series of enantiomerically pure (Z)-(?)-4-(1′-alkyloxy-1′-alkyloxycarbonyl-methylidene)-5(R)-[(1R)-menthyloxy]-γ-butyrolactones were synthesized and characterized in good to excellent yields via O-alkylation of (4R,5R)-(?)-4-ethoxyoxalyl-5-[(1R)-menthyloxy]-γ-butyrolactone with alkyl halides in the presence of K₂CO₃ in acetone at room temperature.     

Interactions of γ-Cyclodextrin with the Mixed Micelles of Anionic Surfactants and Their Inclusion Complexes Formation

Interactions of γ-cyclodextrin (γ-CD) with the single and mixed micelles of sodium dodecyl sulfate (SDS) and sodium lauroyl sarcosine (SLAS) have been studied at different concentrations of γ-CD by using conductivity measurements. From conductivity data, the pure and mixed critical micellar concentration (cmc), the equivalent ionic conductivities of the monomeric species (Λ _m), the associated species (Λ _assc) and the micelle (Λ _mic), the degree of counterion dissociation (χ) in the presence of γ-CD have been evaluated from the slope of the conductivity versus concentration plots for the pure and binary mixture of surfactants. From the dependence of cmc of the surfactantson γ-CD concentration, we have deduced the association constant (K) of surfactant-γ-CD inclusion complexes assuming 2:1 stoichiometry. Theories of Clint, regular solution, and Motomura's have been used for the evaluation of ideality or nonideality of the mixed system. Mixed micelles were found to be rich in SDS content in the presence and the absence of γ-CD. The cmc values have been used to evaluate the transfer of standard free energy of micelles (ΔG⁰ _M,tr) from the aqueous medium to additive medium.     

Gamma ray induced changes on vibrational spectroscopic properties of strontium alumino-borosilicate glasses

The present investigation reports the effect of influence of aluminum ions on radiation damage of strontium borosilicate glasses studied by means of spectroscopic (viz., optical absorption (OA), infrared and Raman spectra). The composition of the glasses chosen for the study is 40SrO–xAl₂O₃–(15-x) B₂O₃–40SiO₂ (x = 5, 7.5, 10), all in mol%. The glasses were synthesized by conventional melt quenching method. Later, the samples were exposed to gamma (γ) radiation dose of strengths 10 kGy and 30 kGy with a dose rate of 1.5 Gy/s using ⁶⁰Co as radiation source. The infrared spectra (IR), Raman spectra and optical absorption (OA) spectra of the samples were recorded at ambient temperature before and after irradiation. The OA spectra of the pre-irradiated samples do not exhibit any absorption bands in the UV–vis regions and IR and Raman spectra exhibited conventional vibrational bands due to different borate, silicate AlO₄ and AlO₆ structural units. The OA spectra of post irradiated samples exhibited a broad absorption band in the wavelength region 600–750 nm; it is attributed to electron trapped color centers. The intensity of this peak is observed to increase with increase of the γ-ray dose. Considerable changes in the intensities of various bands in the IR and Raman spectra were also observed. The changes were explained based on structural modifications taking place in the glass network due to γ-ray irradiation and finally it is concluded that the glasses mixed with 10.0 mol% of Al₂O₃ are relatively more radiation resistant.     

Total synthesis of two γ-butyrolactone containing compounds (Z,11S)-3,4-trans-11-hydroxy-3-methyldodec-cis-6-en-4-olide and (Z)-3,4-trans-11-oxo-3-methyldodec-cis-6-en-4-olide

The first total synthesis of (Z,11S)-3,4-trans-11-hydroxy-3-methyldodec-cis-6-en-4-olide and (Z)-3,4-trans-11-oxo-3-methyldodec-cis-6-en-4-olide was accomplished using Jacobsen hydrolytic kinetic resolution, Ohira–Bestmann reaction, regioselective alkyne addition to terminal carbon atom of epoxide, intramolecular TEMPO/BAIB mediated oxidative lactonization and partial hydrogenation as the key steps.     

CH4 reforming with CO2 for syngas production over La2O3 promoted Ni catalysts supported on mesoporous nanostructured γ-A12O3

Nanostructured -y-A12O3 with high surface area and mesoporous structure was synthesized by sol-gel method and employed as catalyst support for nickel catalysts in methane reforming with carbon dioxide. The prepared samples were characterized by XRD, N2 adsorption-desorption, TPR, TPO, TPH, NH3-TPD and SEM techniques. The BET analysis showed a high surface area of 204 m2.g-1 and a narrow pore-size distribution centered at a diameter of 5.5 nm for catalyst support. The BET results revealed that addition of lanthanum oxide to aluminum oxide decreased the specific surface area. In addition, TPR results showed that addition of lanthanum oxide increased the reducibility of nickel catalyst. The catalytic evaluation results showed an increase in methane conversion with increasing lanthanum oxide to 3 mol% and further increase in lanthanum content decreased the catalytic activity. TPO analysis revealed that the coke deposition decreased with increasing lanthanum oxide to 3 mol%. SEM and TPH analyses confirmed the formation of whisker type carbon over the spent catalysts. Addition of steam and Oxide to drv reformin feed increased the methane conversion and led to carbon free ooeration in combined orocesses.