Poly(4-Vinylpyridinium)Hydrogen Sulfate Catalyzed an Efficient and Ecofriendly Protocol for the One-Pot Multicomponent Synthesis of 1,8-Acridinediones in Aqueous Medium

Table 2

P(4-VPH)HSO₄ catalyzed one-pot synthesis of 1,8-acridinediones (5a–k and 6a–k).

Entry^a	Aldehyde	Product	Time (min)	Yield^b(%)	Melting point (°C)
					Found	Lit. [Ref.]
1	Benzaldehyde	5a	15	92	278–280	279–281 [16]
2	4-Chlorobenzaldehyde	5b	10	94	297–299	298-299 [16]
3	3-Nitrobenzaldehyde	5c	15	89	278–281	282–284 [16]
4	4-Methoxybenzaldehyde	5d	10	91	306–308	304–306 [16]
5	3,4-Dimethoxybenzaldehyde	5e	10	93	355-356	—
6	4-Hydroxybenzaldehyde	5f	15	90	305–307	307–309 [16]
7	3-Methoxy-4-hydroxybenzaldehyde	5g	15	90	281–283	—
8	3-Ethoxy-4-hydroxybenzaldehyde	5h	20	88	299–302	—
9	5-Bromo-2-hydroxybenzaldehyde	5i	20	91	272–274	—
10	3,5-Dibromo-2-hydroxybenzaldehyde	5j	20	90	250-251	—
11	5-Chloro-2-hydroxybenzaldehyde	5k	20	92	295–297	—
12	Benzaldehyde	6a	10	93	258–260	258–260 [18]
13	4-Chlorobenzaldehyde	6b	10	95 (93, 90, 89, 86, 84)^c	299–301	298–300 [18]
14	3-Nitrobenzaldehyde	6c	15	88	290–293	294–296 [18]
15	4-Methoxybenzaldehyde	6d	10	90	273-274	272-273 [23]
16	3,4-Dimethoxybenzaldehyde	6e	10	94	259–261	258–260 [13]
17	4-Hydroxybenzaldehyde	6f	15	92	361–363	>300 [23]
18	3-Methoxy-4-hydroxybenzaldehyde	6g	15	92	294–296	294-295 [18]
19	3-Ethoxy-4-hydroxybenzaldehyde	6h	15	89	280–282	—
20	5-Bromo-2-hydroxybenzaldehyde	6i	20	90	254-255	—
21	3,5-Dibromo-2-hydroxybenzaldehyde	6j	20	90	294-295	—
22	5-Chloro-2-hydroxybenzaldehyde	6k	20	92	234–236	—

^aReaction conditions: 1,3-cyclohexanedione/dimedone (2 mmol), arylaldehyde (1 mmol), ammonium acetate (3 mmol), and P(4-VPH)HSO₄ (0.02 g), heat at 80°C for 10–20 min in 5 mL of H₂O.
^bIsolated yields.
^cYields refer to the reusability of the catalyst over additional five times.