Table 2.

Synthesis of polyhydroquinoline derivatives by using MSN/C₃N₄/CNH catalyst under solvent free conditions.

Entry	R	R′	Yield (%)
1	C6H5	Et	94
2	C6H5	Me	94
3	4-NO2C6H5	Et	96
4	4-NO2C6H5	Me	95
5	4-ClC6H5	Et	96
6	2-BrC6H5	Et	97
7	4-MeC6H5	Et	90
8	4-OHC6H5	Et	92
9	3-EtO-4-OHC6H5	Et	88

Reaction conditions: aldehyde (1 mmol), dimedone (1 mmol), ethyl acetoacetate (1 mmol), ammonium acetate (1.4 mmol), catalyst (10 mg) and reaction time (15 min).