A Simple and Green Procedure for the Synthesis of 5-Arylidenerhodanines Catalyzed by Diammonium Hydrogen Phosphate in Water

Table 2

Diammonium hydrogen phosphate catalyzed synthesis of 5-arylidenerhodanines^a.

Entry	𝑅	Time (min)	Product	Yield (%)^b	Mp (°C) found	Mp (°C) reported
1	2,4-Cl2C6H3	18	3a	86	233–235	233-234 [12]
2	4-CH3C6H4	14	3b	85	222–224	221–223 [12]
3	4-CH3OC6H4	17	3c	88	248–250	249-250 [12]
4	2-ClC6H4	10	3d	88	180-181	181-182 [12]
5	4-FC6H4	9	3e	80	218-219	219 [1]
6	4-HOC6H4	13	3f	83	308–310	310 [16]
7	4-BrC6H4	15	3g	82	228–230	230 [1]
8	3-NO2C6H4	16	3h	90	263–265	263–265 [12]
9	4-ClC6H4	13	3i	81	228–230	229-230 [12]
10	C6H5	8	3j	86	204–206	205–207 [12]
11	2-HOC6H4	16	3k	84	222-223	221-222 [21]
12	2-Furyl	4	3l	85	227–229	228-229 [12]
13	4-HO-3-CH3OC6H3	11	3m	84	231-232	231–231.5 [21]

aReaction condition: aldehyde (2.5 mmol), rhodanine (2.5 mmol), (NH₄)₂HPO₄ (0.25 mmol), 90°C, and water (3 mL).
bIsolated yield.