Table 3.

Optimization of the reaction conditions for the synthesis of 5-aryl 1H- tetrazole derivatives^a.

Entry	Solvent	Catalyst (mol %)	Temperature (°C)	Time (min)	Yield (%)b	TONc	TOFd
1	H2O	0.9	40	20	97	108	323
2	MeOH	0.9	40	20	80	88.9	267
3	EtOH	0.9	40	20	70	77.8	233
4	THF	0.9	40	20	20	22.2	66.6
5	CH3CN	0.9	40	20	40	44.4	133.3
6	CHCl3	0.9	40	20	30	33.3	100
7	CH2Cl2	0.9	40	20	30	33.3
8	Solvent-free	0.9	40	20	70	77.8	233
9	H2O	–	40	24 h	–	–	–
10	H2O	0.4	40	20	70	140	420
11	H2O	0.6	40	20	85	94	282
12	H2O	1	40	20	90	100	300
13	H2O	1.4	40	20	75	83	249
14e	H2O	0.9	40	24 h	30	33.3	1.4
15f	H2O	0.9	40	24 h	50	55.5	2.3
16	H2O	0.9	rt	20	60	66.6	200
17	H2O	0.9	60	20	97	108	323
18	H2O	0.9	80	20	85	94.4	283
19	H2O	0.9	100	20	75	83.3	250
20	H2O	0.9	40	10	75	83	498
21	H2O	0.9	40	30	90	100	200

Significant values are in bold.

^aBenzaldehyde (1.0 mmol), hydroxy amine hydrochloride (1.0 mmol), Sodium azide (1.2 mmol) and Fe₃O₄@SiO₂-Im[Br]-SB-Cu (II) (0.9 mol%, 0.012 g).

^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 (0.012 gr).

^fFe₃O₄@SiO₂-Im[Br] (0.012 gr).