Table 1.
| ||||
---|---|---|---|---|
Entry |
Solvent |
Base [wt %] |
Residence t [min] |
Yield 5 [%] |
1 |
THF/CH2Cl2 (1:1) |
7 |
20 |
19 |
2 |
THF/CH2Cl2 (1:1) |
7 |
40 |
42 |
3 |
THF/CH2Cl2 (1:1) |
7 |
60 |
45 |
4 |
THF/CH2Cl2 (1:1) |
14 |
30 |
49 |
5 |
THF/CH2Cl2 (1:1) |
21 |
30 |
46 |
6 |
THF |
7 |
20 |
50 |
7 |
THF |
21 |
30 |
79 |
8 |
THF |
42 |
18 |
84 |
9 |
THF |
56 |
14 |
57 |
10 |
THF |
42[b] |
24 |
82 |
[a] Conditions: HPLC K120 Knauer Analytical pump with thioacetic acid and propargyl bromide (0.4 m) in dry solvent, column: K2CO3/sand (20 g total) in OmniSep® column (15×150 mm). [b] Column: repacked Biotage® SNAP Ultra cartridge (30 g total). The column volume and, therefore, flow rate was varied between each run due to the percentage of base.