Table 1 The yield of pyrazole derivative 5a obtained using various catalysts under ultrasonic irradiation
Entry | Catalyst | Loading (mol%) | Time (min.) | Yields (%) |
|---|---|---|---|---|
1 | None | - | 180 | No reaction |
2 | EtONa | 100 | 60 | Traces |
3 | Et3N | 5 | 45 | 73 |
4 | Et3N | 10 | 45 | 67 |
5 | Cu(OTf)2 | 5 | 60 | No reaction |
6 | Cu(OTf)2 | 10 | 60 | No reaction |
7 | Cu(OTf)2/ Et3N | 5:5 | 45 | 90 |
8 | Cu(OTf)2/ Et3N | 10:5 | 60 | 90 |