Copper Perchlorate Hexahydrate: An Efficient Catalyst for the Green Synthesis of Polyhydroquinolines under Ultrasonication

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