Bare magnetic nanoparticles: sustainable synthesis and applications in catalytic organic transformations

Mini-review: Ferrite nanoparticles in the catalysis

Review on nanomaterials: Synthesis and applications

Magnetic nanoparticles have emerged recently as an alternative for the easy separation of nanosized catalysts from reaction mixtures by employing an external magnetic field. These magnetic nanoparticles have been used as supports for catalysts and/or as part of an active catalytic site. Herein, special attention is given to identify the main synthetic steps required to develop both precious‐ and nonprecious‐metal‐catalyzed CC and CX coupling reactions by using magnetically separable catalysts.

Recent Applications of Magnetically Recoverable Nanocatalysts in CC and CX Coupling Reactions

The survival rate, p , of a measured inoculum of Staph. aureus in a standard volume of denbrinated blood, is a reliable quantitative measure of the bactericidal power of blood. The number of viable organisms in the inoculum and in the blood-bacterium mixture may be estimated with the necessary accuracy by counts of colonies developing from measured volumes of the fluids let fall on to the surface of solid media. Fildes' agar was the most suitable medium for this surface-viable count, and was selected on the basis of four criteria; of the media tested it yielded the highest counts, and the counts conformed most closely to a Poisson series; and on it the mean colony size was maximum, and the coefficient of variation of colony size was minimum. On this medium, the close conformity of the separate count values to a Poisson series enabled the standard error of the survival rate to be determined from a simplification of the general expression for the standard error of a ratio. The number of colonies growing from a sample of a blood-bacterium mixture may be reduced, not by killing of the individual cocci, but as a result of their aggregation either by agglutinins in the blood, or in the cytoplasm of leucocytes that are phagocytic but not bactericidal. It appears that these mechanisms are unlikely to operate in blood-bacterium mixture containing relatively few organisms; in such mixtures the survival rate is a reflexion of the killing power only. The immunological significance of p has not been investigated, but the range of values for healthy human adults differs significantly from that for sufferers from chronic staphylococcal infection. Moreover, by the technique employed differences may be detected between individual values of p that cannot reasonably be attributed to technical or sampling errors.

The Estimation of the Bactericidal Power of the Blood. With a Note by J. O. IRWIN.

Copper ferrite nano material as reusable heterogeneous initiator in the synthesis of β, γ-unsaturated ketones and allylation to acid chlorides are presented The reaction of allylichalides with various acid chlorides is achieved in the presence of copper ferrite nano powders at room temperature in tetrahydrofuran (THF) The present method is first of its kind in the synthesis of title compounds without any additive/ co-catalyst The nano catalyst is easily recovered and its reusability is recorded

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Nano copper ferrite: A reusable catalyst for the synthesis of β , γ -unsaturated ketones

Copper ferrite nano material (catalyst) are reusable heterogeneous initiator in the synthesis of 1, 4-dihydropyridines is presented. The reaction of substituted aromatic aldehydes, ethyl acetoacetate and ammonium acetate was achieved in presence of copper ferrite nano powders at room temperature in ethanol. The nano catalyst was easily recovered and its reusability was recorded.

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One-Pot, Three-Component Synthesis of 1, 4-Dihydropyridines by Using Nano Crystalline Copper Ferrite

Quinazolin-4-ones linked to 1,2,3-triazol (10) were identified as inhibitors of the bisphosphonate BPH-700 transcriptional factor from a high throughput screen. A series of 1,4-disubstituted triazoles (10a–j) were synthesized by the Cu-catalyzed azide-alkyne cyclo addition of 5-methoxy-2-nitro-4-(prop-2-yn-1-yloxy) benzamide (6) with various substituted azido benzenes (7) in the presence of CuSO4 under aerobic conditions followed by click reaction with substituted aldehydes. The target compounds were screened for antitubercular activity against Mycobacterium tuberculosis H37Rv by Broth micro dilution method using Lowenstein Jensen medium (LJ) (MIC < 9 μg/mL). Majority of the compounds 10b, 10d, 10e, 10i and 10j displayed good antitubercular activity with MIC 7–11 μg/mL. Further, 10e exhibited a promising inhibition with MIC 7 μg/mL, compared to the reference drug Rifampicin. Docking studies have been performed to understand the interactions between the synthesized compounds and the active site of pantothenate synthetase Mycobacterium tuberculosis H37Rv organism. The study revealed that the target compounds showed good affinity toward the protein when compared to the standard drug Pefloxacin. Further, 10b was found to interact with three amino acids, viz., Gln92, Arg200, Ser196, as evidenced by the large interaction energy (ΔG = −8.16 kcal/mol). Besides the above, the synthesized quinazolinone triazoles 10a–j were evaluated for their antibacterial activities against a panel of Gram +ve and Gram –ve bacteria. Among them 10a, 10e, 10 h and 10j showed promising broad spectrum antibacterial activity with inhibition in the range of 19–33-mm diameter of inhibition zone (DIZ).

Design, synthesis and molecular docking studies of quinazolin-4-ones linked to 1,2,3-triazol hybrids as Mycobacterium tuberculosis H 37 Rv inhibitors besides antimicrobial activity

Nano size nickel ferrite, copper ferrite, zinc ferrite, nickel copper ferrite, nickel zinc ferrite and nickel copper zinc ferrite powders have been prepared by citrate gel precursor method and calicinated at 800 o C temperature. The resulting powders were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The ferrite powders showed XRD line broadening and sizes of the crystals were calculated 20-65 nm at 800 o C temperature. Comparing the size of ferrites by addition of transition metal were discussed.

I. V. Kasi Viswanath

Papers

Review on nanomaterials: Synthesis and applications

Nano copper ferrite: A reusable catalyst for the synthesis of β , γ -unsaturated ketones

One-Pot, Three-Component Synthesis of 1, 4-Dihydropyridines by Using Nano Crystalline Copper Ferrite

Design, synthesis and molecular docking studies of quinazolin-4-ones linked to 1,2,3-triazol hybrids as Mycobacterium tuberculosis H 37 Rv inhibitors besides antimicrobial activity

Synthesis and Characterization of Nano Ferrites by Citrate Gel Method