The influence of different catalysts for the preparation of quinazoline-2,4(1H,3H)-dione^a.

Entry	Catalyst	Yieldb (%)
1	DFNS	—
2	DFNS/cellulose	—
3	DFNS/cellulose-ZnO	96
4	Cellulose-ZnO	98

^aReaction conditions: substrate (1.0 mmol), isocyanide (1.0 mmol), catalyst (5 mg), Cs₂CO₃ (1.0 mmol), DMF (5 mL), 70 °C, CO₂ balloon, 3 hours.

^bIsolated yield.