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

Table 3

Different amounts of the alum as catalyst for the synthesis of 4i ^a.

Entry	Alum (mol%)	Yield (%)^b
1	5	51
2	10	65
3	15	81
4	20	94
5	30	96

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.