Table 1.

Optimization of the reaction conditions for the synthesis of 1-aryl 1-H tetrazole derivatives.

Entry	Solvent	Catalyst (mol %)	Temperature (°C)	Time (min)	Yield (%)b	TONc	TOF (h−1)d
1	H2O	0.6	40	20	97	162	486
2	MeOH	0.6	40	20	75	125	375
3	EtOH	0.6	40	20	70	117	350
4	THF	0.6	40	20	30	50	150
5	CH3CN	0.6	40	20	60	67	201
6	CHCl3	0.6	40	20	40	67	201
7	CH2Cl2	0.6	40	20	40	80	240
8	Solvent-free	0.6	40	20	85	142	426
9	H2O	–	40	24 h	–	–	–
10	H2O	0.4	40	20	80	133	399
11	H2O	0.9	40	20	90	150	450
12	H2O	1	40	20	85	142	426
13	H2O	1.4	40	20	78	130	390
14e	H2O	0.008 gr	40	24 h	30	50	2.08
15f	H2O	0.008 gr	40	24 h	50	83	3.5
16	H2O	0.6	rt	20	60	100	300
17	H2O	0.6	60	20	95	158	474
18	H2O	0.6	80	20	85	142	426
19	H2O	0.6	100	20	70	117	351
20	H2O	0.6	40	10	70	117	702
21	H2O	0.6	40	30	92	153	306

Significant values are in bold.

^aAniline (1.0 mmol), Triethyl orthoformate (1.2 mmol), Sodium azide (1 mmol) and Fe₃O₄@SiO₂-Im[Br]-SB-Cu (II).

^bIsolated yield.

^cTurnover numbers (TONs) defined as mmol of transformed substrate molecules per mmol of catalyst.

^dTurnover frequencies (TOFs) defined as mmol of substrate molecules transformed per mmol of catalyst per hour.

^eFe₃O₄ (0.008 gr).

^fFe₃O₄@SiO₂-Im[Br] (0.008 gr).