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

Table 4

Different reaction temperatures in model reaction for the synthesis of 4i ^a.

Entry	Reaction temperature (°C)	Reaction time (min)	Yield (%)^b
1	r.t.	120	Trace
2	70	60	87
3	90	30	94
4	110	30	95

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), alum (20 mol%).
bIsolated yields.