Copper ferrite nanomaterial
Melting points were determined by Thieles tube method. 1H-NMR spectra were recorded on a Bruker AM 300 MHz spectrometer using CDCl3 as a solvent and tetramethylsilane as an internal standard. The chemical shifts are expressed in
The catalyst was synthesized by citrate gel precursor method [
To the reaction mixture of aldehyde (1 mmol), amine (1 mmol), trimethylsilyl cyanide TMSCN (1.5 mmol) was added to a solution of nano copper ferrite (CuFe2O4) catalyst (15 mg) and glacial acetic acid (1 mL), in water (50 mL), and the resulting mixture was stirred vigorously at room temperature for appropriate time. The reaction was monitored by TLC. After completion of the reaction, as indicated by TLC, the reaction mixture was filtered and washed with EtOAc (2 × 20 mL and the catalyst was separated by filtration. The organic solvent was removed under reduced pressure. After purification by chromatography on silica gel (ethyl acetate/n-hexane 20:80),
We wish to report the best reaction conditions for the synthesis of
Effect of amount of catalyst on the synthesis of 2-(4-Nitrophenyl)-2-(phenylamino)acetonitrile (
Entry | Amount of catalyst (mg) | Reaction time | aYield (%) |
---|---|---|---|
1 | 0 (not catalyst) | 18 hrs | — |
2 | 0 (not catalyst) | 24 hrs | — |
3 | 5 | 72 min | 74 |
4 | 10 | 55 min | 82 |
5 | 15 | 55 min | 98 |
6 | 25 | 55 min | 84 |
7 | 30 | 55 min | 79 |
The synthesis of
The same reaction was used to optimize the amount of the catalyst. The results show (Table
Effect of amount of catalyst on the synthesis of 2-(4-Nitrophenyl)-2-(phenylamino)acetonitrile (
Entry | Amount of catalyst (mg) | Reaction time | aYield (%) |
---|---|---|---|
1 | 5 | 80 min | 69 |
2 | 10 | 65 min | 77 |
3 | 15 | 66 min | 90.5 |
4 | 25 | 66 min | 78 |
5 | 30 | 68 min | 71 |
The reaction was then performed in various solvents using nano copper ferrite (CuFe2O4) with AcOH as the catalyst to identify the best condition. It suggests that nano copper ferrite (CuFe2O4) and AcOH (with amount of 15 mg) is the best catalyst amount in aqueous medium for the reaction (Table
Synthesis of 2-(4-Nitrophenyl)-2-(phenylamino)acetonitrile (
Entry | Solvent | aYield (%) |
---|---|---|
1 | H2O | 98 |
2 | C2H5OH | 59 |
3 | DMF | 81 |
4 | DMSO | 80 |
5 | CHCl3 | 77 |
6 | C6H5CH3 | 79 |
7 | CH3OH | 72 |
8 | CH2Cl2 | 78 |
9 | CCl4 | 83 |
10 | C6H6 | 76 |
11 | n |
69 |
In addition to different benzaldehyde derivatives, this reaction was also tested with alkyl aldehydes or (aliphatic aldehydes) such as acetaldehyde, isobutyraldehyde, propionaldehyde and butyraldehyde, and aniline, their yields are as follows: 72, 76, 79, 82%.
The results listed in Tables
Synthesis of 2-(4-Nitrophenyl)-2-(phenylamino)acetonitrile (
Entry | Solvent | aYield (%) |
---|---|---|
1 | H2O | 90.5 |
2 | C2H5OH | 51 |
3 | DMF | 73 |
4 | DMSO | 72.5 |
5 | CHCl3 | 70 |
6 | C6H5CH3 | 71 |
7 | CH3OH | 65 |
8 | CH2Cl2 | 70.5 |
9 | CCl4 | 77 |
10 | C6H6 | 72 |
11 | n |
64 |
One reason for the increase in the catalytic activity may be related to the number of available active sites. A proposed mechanism for the rule of nano copper ferrite (CuFe2O4) catalyst with AcOH in the reaction of aldehydes, amine and trimethylsilyl cyanide is presented in Scheme
Suggested mechanism for the synthesis of
We suggest a mechanism for the formation of
Considering the above observations, we carried out a series of reactions using various carbonyl compounds, amines, and TMSCN in presence of nano copper ferrite (CuFe2O4) with (15 mg) AcOH in water as solvent (Scheme
Synthesis of
Entry | Carbonyl compound | Amine | Product | Time (min) | aYield (%) | Mp (°C) |
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1 |
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75 | 92 | 115–117 |
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2 |
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70 | 90 (90, 89.5, 89.5, 89)b | 104–106 |
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3 |
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73 | 92 | 83–85 |
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4 |
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75 | 94.5 | 100–102 |
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5 |
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70 | 94 (93.5, 93, 93, 92.5)b | 109-110 |
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6 |
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69 | 91 (91, 90, 90, 89.5)b | 95–97 |
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7 |
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68 | 94 (94, 93, 92.5, 92)b | 70–73 |
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8 |
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65 | 93 | 121–123 |
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9 |
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55 | 98 (98, 98, 97, 97)b | 90–92 |
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10 |
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50 | 93 (93, 92.5, 92, 92)b | 73-74 |
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11 |
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81 | 72 | 80–83 |
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12 |
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75 | 75 | 49–52 |
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13 |
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65 | 78 | 110–112 |
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14 |
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62 | 93 | 107–109 |
XRD studies were carried out to the above nano ferrite and XRD spectrum is presented in Figure
XRD spectrum of nano copper ferrite (CuFe2O4) at 500°C.
SEM image of nano copper ferrite (CuFe2O4).
TEM image of nano copper ferrite (CuFe2O4).
At the end of the reaction, the catalysts could be recovered by a simple filtration. The recycled catalyst could be washed with dichloromethane and subjected to a second run of the reaction process with the same substrate. The results of the first and subsequent experiments were almost consistent in yields (98, 98, 97, 97% after four runs) (Table
In conclusion, we have demonstrated a highly efficient and convenient method for the synthesis of
The authors declare that there is no conflict of interests regarding the publication of this paper.