Table 3. Reaction conditions and yields for the Knoevenagel condensation (5 → 10)^a.

Compound	Catalyst	Solvent (DCM : MeOH)	t, h	Yield, %
10a	(PhNH3)2CuCl4	1 : 1	38	Quant.
10b	(PhNH3)2CuCl4	1 : 9	19	Quant.
10c	—	1 : 3	48	77
10d	(PhNH3)2CuCl4	1 : 4	19	Quant.
10e	(PhNH3)2CuCl4	1 : 5	46	86
10f	(PhNH3)2CuCl4	1 : 4	21	55
10g	(PhNH3)2CuCl4	1 : 4	18	86
10h	—	1 : 2	48	60
10i	(PhNH3)2CuCl4	1 : 4	24	Quant.

^aMeldrum's acid, DCM : MeOH, 40 °C.