Efficient Knoevenagel Condensation Reactions Catalyzed by Activated Gel Zirconium(IV) Oxide

Table 1

Reaction time, yields, and melting points of the products (3a–j).

Entry	X	Time (min)	Yield (%)^a	Mp (^°C)
1	H	20	88	188-189
2	4-Cl	25	83	144-145
3	3-NO2	20	90	151-152
4	4-NO2	10	96	162-163
5	2, 4-(NO2)2	5	97	172-173
6	4-F	15	90	183-184
7	4-CF3	10	98	133-134
8	4-OCH3	25	90	166-167
9	4-CH3	30	91	178-179
10	4-Br	30	91	184-185

Reaction conditions: 1 (1 mmol), 2 (1 mmol), ZrOCl₂·8H₂O/NaNH₂ (15 mol %), in THF (5 mL) at 25^°C.
^aIsolated yield.