Optimization of reaction conditions for the synthesis of chromonesa.
Entry | Reagents (equiv.) | Solvents | Temp. (°C) | Time (h) | Yieldb (%) |
---|---|---|---|---|---|
1 | I2 (0.5) | Ethanol | 80 | 72 | 7 |
2 | I2 (1.0) | Ethanol | 80 | 72 | 14 |
3 | I2 (1.0) | EG | 140 | 72 | nd |
4 | I2 (1.0) | Acetonitrile | 80 | 72 | nd |
5 | I2 (1.0) | Toluene | 80 | 72 | nd |
6 | I2 (1.0) | EtOAc | 80 | 72 | nd |
7 | I2 (1.0) | DMF | 140 | 72 | nd |
8 | I2 (1.0) | NMP | 140 | 72 | nd |
9 | I2 (1.0) | DMSO | 140 | 72 | nd |
10 | I2 (1.0) | Xylene | 140 | 72 | nd |
11 | I 2 (1.0) | PEG-400 | 140 | 7 | 84 |
12 | I2 (0.1) | PEG-400 | 140 | 72 | 13 |
13 | I2 (0.3) | PEG-400 | 140 | 72 | 39 |
14 | I2 (0.5) | PEG-400 | 140 | 72 | 58 |
15 | NaI (1.0) | PEG-400 | 140 | 72 | nd |
16 | CuI (1.0) | PEG-400 | 140 | 72 | nd |
17 | KI (1.0) | PEG-400 | 140 | 72 | 8 |
18 | I2 + KI (1.0) | DMF | 140 | 72 | 28 |
19 | I2 + KI (1.0) | Toluene | 80 | 72 | 32 |
20 | I2 + KI (1.0) | Ethanol | 80 | 72 | 22 |
21 | PhI(OAc)2 | PEG-400 | 140 | 48 | nd |
Reagents and conditions: different reagents were screened as given in Table 1 with varied temp. and equivalencies.
Isolated yield, nd - not detected.