Table 4 Optimization of the Ullmann N-arylation reaction.a
From: A copper-doped ZIF-8: a high-performance catalyst for eco-friendly Ullmann and Biginelli reactions
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|---|---|---|---|---|---|---|
Entry | Solvent | Base (mmol) | Cat. (mg) | Yield (%) | TON | TOF(h− 1) |
1 | DMSO | K2CO3 | - | 0 | 0 | 0 |
2 | DMSO | K2CO3 | 40.0 | 78 | 150 | 6.8 |
3a | DMSO | K2CO3 | 50.0 | 93 | 143.1 | 6.5 |
4 | DMSO | K2CO3 | 60.0 | 70 | 89.7 | 4.1 |
5 | DMSO | K2CO3 | 70.0 | 60 | 65.9 | 3 |
6 | DMSO | K2CO3 | ZIF-8 (50) | Trace | - | - |
7 | DMSO | K2CO3 | Cu(NO3)2·6H2O (50) | 25 | 38 | 2 |
8 | DMSO | K2CO3 | Cu(NO3)2·6H2O (50) + ZIF-8 (50) | 35 | 53.8 | 2.4 |
9 | H2O | K2CO3 | 50.0 | 0 | 0 | 0 |
10 | EtOAc | K2CO3 | 50.0 | 20 | 30.8 | 1.4 |
11 | CH3CN | K2CO3 | 50.0 | 42 | 64.6 | 2.9 |
12 | Toluene | K2CO3 | 50.0 | 30 | 46.2 | 2.1 |
13 | THF | K2CO3 | 50.0 | 45 | 69.2 | 3.1 |
14 | EtOH | K2CO3 | 50.0 | 55 | 84.6 | 3.8 |
15 | DMF | K2CO3 | 50.0 | 85 | 130.8 | 5.9 |
16 | DMSO | - | 50.0 | 0 | 0 | 0 |
17 | DMSO | NaOH | 50.0 | 75 | 115.4 | 5.2 |
18 | DMSO | Et3N | 50.0 | 63 | 96.9 | 4.4 |
19 | DMSO | NaOAc | 50.0 | 70 | 107.7 | 4.9 |
20 | DMSO | K3PO4 | 50.0 | 60 | 92.3 | 4.2 |
21b | DMSO | K2CO3 | 50.0 | 65 | 100 | 4.5 |
22c | DMSO | K2CO3 | 50.0 | 50 | 76.9 | 3.5 |
