NIKOORAZM ET AL.
3 of 20
2
.2 | Preparation of copper (II) or nickel
anhydrous sodium sulfate and, then, concentrated to give
the crude solid product.
(II) immobilized on mesoporous MCM-41
nanoreactor
Initially, the modified mesoporous MCM-41 nanoreactor
by 3-chloropropyltrimtoxysilane (CPTMS@MCM-41) was
prepared based on a newly reported procedure.
2.4 | General procedure for the synthesis
of pyranopyrazoles compounds
[
69]
Subsequently, CPTMS@MCM-41 (1.0 g) was dispersed in
toluene by sonication for 20 min and, then, 3 mmol
A mixture of ethyl acetoacetate (1.0 mmol, 0.130 g), alde-
hyde (1.0 mmol), malononitrile (1.0 mmol, 0.066 g), hydra-
zine hydrate (1.0 mmol, 0.050 g) and Cu-Cytosine@MCM-41
(0.02 g, 2.12 mol%) or Ni-Cytosine@MCM-41 (0.02 g,
0.07 mol%) in water as solvent was stirred in an oil bath at
(
0.333 g) of cytosine was added to the reaction mixture.
ꢀ
The obtained mixture was stirred for 72 hr at 100 C. The
solid product (cytosine@MCM-41) was isolated by simple
filtration and washed with ethanol. In order to prepare
Ni-Cytosine@MCM-41, 1.0 g of Cytosine@MCM-41
was dispersed in ethanol by sonication for 20 min
and, then, mixed with 2 mmol (0.365 g) of Ni
ꢀ
80 C for different periods of time (Tables 6 and 7). After
completion of the reaction (observed by TLC), the mixture
was cooled down to room temperature. Afterwards, the cat-
alyst was separated using simple filtration and, then,
washed by hot ethyl acetate. The residue was extracted by
ethyl acetate and water. The organic layer was dried over
anhydrous sodium sulfate and, then, the solvent was evapo-
rated. The pure product was obtained through recrystalliza-
tion in ethanol.
(
NO ) .6H O. Afterwards, the obtained mixture was
3 2 2
ꢀ
stirred for 20 hr at 80 C. This procedure is outlined in
Scheme 1. Moreover, Cu-Cytosine@MCM-41 was pre-
pared by stirring Cytosine@MCM-41 (1 g) and Cu
ꢀ
(
NO ) .3H O (2 mmol, 0.483 g) in ethanol at 50 C for
3
2
2
2
0 hr as outlined in Scheme 1.
2
.3 | General procedure for the synthesis
2.5 | Selected spectral data
of 5-substituted 1H-tetrazoles
Selected spectral data is given in the Supporting Information.
A mixture of NaN (1.3 mmol, 0.845 g) and benzonitrile
3
derivative (1 mmol) in the presence of Cu-Cytosine@MCM-
4
1 (0.03 g, 3.1 mol%) or Ni-Cytosine@MCM-41 (0.03 g,
2.6 | 2-(1H-tetrazol-5-yl)benzonitrile
ꢀ
0.1 mol%) was stirred at 120 C in poly ethylene glycol
1
(PEG-400) as a solvent. After completion of the reaction
H NMR (400 MHz, DMSO): δH = 17.25 (br, 1H),
[
which was observed by thin-layer chromatography (TLC)],
8.13–8.09 (t, J = 8 Hz, 2H), 7.98–7.94 (t, J = 8 Hz, 1H),
13
the catalyst was isolated by simple filtration then, the prod-
ucts were extracted by an aqueous solution of HCl (4 N)
and ethyl acetate. The organic solvent was dried over
7.83–7.79 (t, J = 8 Hz, 1H) ppm. C NMR (100 MHz,
DMSO): δC = 134.9, 133.8, 131.4, 129.7, 127.6, 117.2,
110.2 ppm.
FIGURE 1 The low XRD patterns of Ni-Cytosine@MCM-41
FIGURE 2 TGA diagrams of Cu-Cytosine@MCM-41 (a) and
(
a) and Cu-Cytosine@MCM-41 (b)
Ni-Cytosine@MCM-41 (b)