The synthesis of 1-substituted-1H-tetrazoles catalyzed by (Fe₃O₄@NFC@NSalophCu)CO₂H^a.

Entry	Aldehyde	Time (min)	Tetrazole	Yieldb (%)	Mp (°C)	TON	TOF	Ref. (lit)
1a		20		98	63	326.6	990	61
2b		30		90	155	300	600	61
3c		30		95	176–177	316.6	633	61
4d		15		90	92–93	300	682	61
5e		15		97	114–115	323.3	1293	61
6f		45		80	200	266.6	355.4	61
7g		50		90	139–140	300	360	62
8h		60		90	78–79	300	300	1
9i		30		97	55	323.3	646.5	63
10j		30		97	67–68	323.3	646.5	64

^aReaction conditions: aniline (1.0 mmol), triethyl orthoformate (1.2 mmol), sodium azide (1.2 mmol), catalyst (0.3 mol%), and solvent-free conditions; 80 °C.

^bIsolated yield.