Molecular Iodine: A Powerful Catalyst for the Knoevenagel Condensation of Isatins with Malononitrile

Table 1

Optimization studies of the condensation of isatin with malononitrile^a.

Entry	I2 (mol%)	Solvent	Temp. (°C)	Time (min)	Yield (%)^b
1	10	CH3CN	60	10	72
2	10	PhMe	60	30	56
3	10	THF	60	20	80
4	10	CHCl3	60	20	71
5	10	MeOH	60	5	86
6	10	EtOH	60	5	97
7	10	EtOH	25	60	59
8	15	EtOH	60	5	96
9	5	EtOH	60	10	76
10	0	EtOH	60	120	32

^aReaction conditions: isatin (1 mmol); malononitrile (1 mmol).
^bIsolated yield.