An Efficient One-Pot Multicomponent Synthesis of 4-Aza-Podophyllotoxin Derivatives in Ionic Liquid

Table 2

Diverse used catalyst in a model reaction for the synthesis of 4i ^a in [bmim][triflate].

Entry	Catalyst (20 mol%)	Yield (%)^b
1	Alum	94
2	p-TSA	90
3	K-10	85
4	S.S.A	80
5	AlCl3	55
6	Et3N	63

aReaction conditions: 4-bromobenzaldehyde 1d (1 mmol), dimedone 2b (1 mmol), and 4-(4-methylphenylamino)furan-2(3H)-one 3d (1 mmol), IL (0.2 mL).
bIsolated yields.