Optimizing the model reaction conditions for the synthesis of perimidine 6d^a.

Entry	Catalyst (g)	Solvent	Temperature (°C)	Time (min)	Yieldb (%)
1	0.0047	EtOH	rt	4	81
2	0.008	EtOH	rt	4	98
3	0.016	EtOH	rt	4	70
4	0.008	MeOH	rt	4	80
5	0.008	DMSO	rt	4	75
6	0.008	CH3CN	rt	10	63
7	0.008	CH2Cl2	rt	15	51
8	0.008	H2O	rt	18	46
9	0.008	EtOH : H2O (1 : 1)	rt	10	81
10	Zeolite-Y (0.008)	EtOH	rt	120	20
11	SO3H@zeolite-Y (0.008)	EtOH	rt	8	89
12	—	EtOH	rt	120	10

^aReaction conditions: benaldehyde (1 mmol), 1,8-diaminonaphthalene (1 mmol), catalyst, in solvent at 25 °C.

^bIsolated yield.