Table 1 Yields of 3a at different reaction conditions
No. | Solvent | Base | Time (h) | Yield (%) |
|---|---|---|---|---|
1 | ethanol | triethylamine | 24 | 15.1 |
2 | acetonitrile | triethylamine | 24 | 35.8 |
3 | DMF | triethylamine | 24 | 25.4 |
4 | 1,4-dioxane | triethylamine | 24 | 12.6 |
5 | acetonitrile | K2CO3 | 24 | 33.2 |
6 | acetonitrile | pyridine | 24 | 20.1 |
7 | acetonitrile | piperidine | 24 | 51.4 |
8 | acetonitrile | piperidine | 18 | 56.6 |
9 | acetonitrile | piperidine | 12 | 42.2 |