Table 2.
Copper perchlorate hexahydrate catalyzed solvent-free synthesis of polyhydroquinolines 1a–1l under ultrasound irradiation.
| Entry | Products | Ar | Time (min) | Yield (%) | mp °C (Lit mp °C) |
|---|---|---|---|---|---|
| (1) | 1a | C6H5 | 20 | 96 | 203-204 (202–204)16 |
| (2) | 1b | 4-MeOC6H4 | 25 | 97 | 257-258 (257–259)16 |
| (3) | 1c | 4-ClC6H4 | 25 | 95 | 244-245 (245-246)12 |
| (4) | 1d | 4-NO2C6H4 | 35 | 88 | 242-243 (242–244)12 |
| (5) | 1e | 3-NO2C6H4 | 35 | 86 | 176-177 (177-178)5 |
| (6) | 1f | 4-FC6H4 | 25 | 94 | 184-185 (184–186)16 |
| (7) | 1g | 4-OHC6H4 | 40 | 89 | 232-233 (232–234)16 |
| (8) | 1h | 2-NO2C6H4 | 25 | 90 | 207-208 (206–208)5 |
| (9) | 1i | 4-BrC6H4 | 30 | 91 | 254-255 (253–255)16 |
| (10) | 1j | 3-ClC6H4 | 25 | 93 | 231-232 (230–232)22 |
| (11) | 1k | 2-ClC6H4 | 25 | 93 | 209-210 (208–210)12 |
| (12) | 1l | 4-MeC6H4 | 25 | 93 | 260-261 (260-261)16 |