Table 2. Scope of different aryl aldehyde and malononitrile for the synthesis of benzylidene derivatives^a.

Entry	R	Timeb (min)	Product	Yieldc (%)	M.P. (°C) (observed)	M.P. (°C) (reported)
1	–C6H5	15	1a	95	83–85	81–83 (ref. 40)
2	4-FC6H4	20	1b	83	124–126	130 (ref. 41)
3	4-ClC6H4	20	1c	89	158–160	160–162 (ref. 40)
4	Furfural	25	1d	92	72–75	70 (ref. 42)
5	4-MeC6H4	20	1e	95	134–136	132–134 (ref. 40)
6	2,5-(OMe)2C6H3	25	1f	85	109–111	110–112 (ref. 43)
7	3-MeC6H4	25	1g	90	75–77	74–75 (ref. 44)
8	4-BrC6H4	20	1h	90	152–154	153–154 (ref. 40)
9	4-OMeC6H4	20	1i	92	121–123	122 (ref. 41)
10	4-NO2C6H4	20	1j	86	159–161	158–160 (ref. 43)
11	2,4,5-(OMe)3C6H2	30	1k	88	134–136	136 (ref. 41)
12	1-Naphthayl	50	1l	82	173–175	174–176 (ref. 44)
13	4-CNC6H4	10	1m	94	152–154	151–153 (ref. 44)

^aReaction condition: aldehyde (1 mmol), malononitrile (1 mmol), SMA (1 mol%).

^bReaction progress monitored by TLC.

^cIsolated yield.