ARIANNEZHAD et al.
1596
Table 4. Synthesis of tetrazoles 2a–2j
mp, °C
Reaction time,
Initial compd. no.
Product no.
Yield, %
min
found
reported
1a
1b
1c
1d
1e
1f
1g
1h
1i
2a
2b
2c
2d
2e
2f
2g
2h
2i
80
100
90
100
110
180
100
180
120
115
90
82
92
91
87
75
85
86
93
82
63–66
132–134
93–95
113–115
174–177
176–180
127–131
156–158
199–203
124–128
64–65
133–135
94–95
114–115
177
183–185
127–131
157–158
201–202
125–127
1j
2j
1
sure. A mixture of 4H-1,2,4-triazol-4-amine (0.42 g,
5 mmol) and potassium carbonate (0.69 g, 5 mmol) in
toluene (60 mL) was added to 0.1 g of C, and the
mixture was refluxed for 12 h. The product (D) was
separated with a strong magnet, washed repeatedly
with ethanol and water, and dried under reduced
pressure. A 0.1-g sample of D was added to a sus-
pension of copper(II) chloride (0.85 g, 5 mmol) in
ethanol, and the mixture was vigorously stirred for 8 h
at 80°C. The resulting copper nanocatalyst (E) was
separated with a strong magnet, washed with ethanol,
and air-dried.
1496, 1302, 1206, 1036, 815, 561. H NMR spectrum
(90 MHz, CDCl3), δ, ppm: 8.39 s (1H), 6.96 m (3H),
2.29 s (6H).
1-(4-Methylphenyl)-1H-tetrazole (2c). IR spec-
trum (nujol), ν, cm–1: 3027, 2914, 2857, 1672, 1608,
1587, 1521, 1506, 1408, 1313, 1217, 1202, 1174,
1110, 1040, 985, 938, 821, 738, 716, 644, 578.
1H NMR spectrum (90 MHz, CDCl3), δ, ppm: 8.16 s
(1H), 7.27–6.92 m (4H), 2.30 s (3H).
1-(4-Methoxyphenyl)-1H-tetrazole (2d). IR spec-
trum (nujol), ν, cm–1: 1667, 1504, 1464, 1243, 1034,
1
826. H NMR spectrum (90 MHz, CDCl3), δ, ppm:
1-Aryl-1H-tetrazoles 2a–2j (general procedure).
A mixture of 2 mmol of aromatic amine 1a–1j, 0.13 g
(2 mmol) of sodium azide, 0.296 g (2 mmol) of triethyl
orthoformate, and 50 mg of the copper nanocatalyst
was stirred at 100°C until no further progress in the
conversion was observed according to the TLC data.
The mixture was allowed to cool down to room tem-
perature, the catalyst was separated by strong magnet,
the mixture was poured onto ice, and the organic layer
was extracted with ethyl acetate (2 ×20 mL). The
combined extracts were dried over anhydrous MgSO4,
filtered, and evaporated, and the residue was recrys-
tallized from ethyl acetate–hexane (1:10). The yields
and melting points of tetrazoles 2a–2j are given in
Table 4.
8.05 s (1H), 6.88 m (4H), 3.7 s (3H).
1-[4-(1H-Tetrazol-1-yl)phenyl]ethan-1-one (2e).
IR spectrum (KBr), ν, cm–1: 3059, 2996, 2962, 1674,
1603, 1589, 1503, 1483, 1411, 1359, 1324, 1303,
1271, 1211, 1186, 1172, 997, 957, 910, 841, 815, 734,
685, 635, 590. 1H NMR spectrum (90 MHz, CDCl3), δ,
ppm: 8.29 s (1H), 8.00–7.09 m (4H), 2.59 s (3H).
1-(4-Bromophenyl)-1H-tetrazole (2f). IR spec-
trum (KBr), ν, cm–1: 3527, 3151, 3045, 2855, 1660,
1589, 1575, 1483, 1402, 1312, 1291, 1224, 1206,
1073, 1008, 827. 1H NMR spectrum (90 MHz, CDCl3),
δ, ppm: 8.07 s (1H), 7.40 d (2H, J = 8.6 Hz), 6.90 d
(2H, J = 8.6 Hz).
1-(2-Chlorophenyl)-1H-tetrazole (2g). IR spec-
trum (KBr), ν, cm–1: 2998, 2866, 1666, 1583, 1502,
1475, 1454, 1439, 1376, 1309, 1264, 1207, 1132,
1058, 1039, 1000, 935, 825, 752, 702, 657. H NMR
spectrum (90 MHz, CDCl3), δ, ppm: 8.07 s (1H), 7.44–
1-Phenyl-1H-tetrazole (2a). IR spectrum (KBr), ν,
cm–1: 3051, 2925, 2854, 1678, 1660, 1585, 1487, 1448,
1316, 1279, 1227, 1209, 1171, 1153, 1076, 986, 899,
1
1
806, 765, 754, 694, 619, 593. H NMR spectrum
(90 MHz, CDCl3), δ, ppm: 8.27 s (1H), 6.98–
7.10 m (4H).
7.60 m (5H).
1-(4-Chlorophenyl)-1H-tetrazole (2h). IR spec-
trum (KBr), ν, cm–1: 2925, 1663, 1581, 1488, 1405,
1311, 1292, 1226, 1205, 1172, 1090, 1006, 984, 829,
1-(2,4-Dimethylphenyl)-1H-tetrazole (2b). IR
spectrum (KBr), ν, cm–1: 3157, 3015, 2876, 1665,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 55 No. 10 2019