Synthesis and chemical properties of 5-alkylsulfonyl-1-(4-nitrophenyl) tetrazoles

Full text of DOI:10.1134/S107042800703030X

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2007, Vol. 43, No. 3, pp. 475–477. © Pleiades Publishing, Ltd., 2007.
Original Russian Text © N.G. Egorova, T.V. Artamonova, G.I. Koldobskii, 2007, published in Zhurnal Organicheskoi Khimii, 2007, Vol. 43, No. 3,
pp. 474–476.
SHORT
COMMUNICATIONS
Synthesis and Chemical Properties
of 5-Alkylsulfonyl-1-(4-nitrophenyl)tetrazoles
N. G. Egorova, T. V. Artamonova, and G. I. Koldobskii
St. Petersburg State Institute of Technology, Moskovskii pr. 26, St. Petersburg, 190013 Russia
e-mail: koldobsk@tu.spb.ru
Received October 5, 2006
DOI: 10.1134/S107042800703030X
While performing studies in the field of synthesis
and properties of 5-alkylsulfonyl-1-aryltetrazoles, we
have developed a simple and efficient procedure for
the preparation of these compounds. The procedure
includes oxidation of the corresponding 5-alkylsul-
fanyl-1-phenyltetrazoles with hydrogen peroxide under
conditions of microwave activation (MW) and subse-
quent nitration of the sulfones thus formed.
C-, N-, and O-centered nucleophiles. Moreover, nu-
cleophilic replacement of the methylsulfonyl group in
such substrates may be regarded as a very promising
method for functionalization of tetrazoles [4]. While
studying chemical properties of 1-aryl-5-(methylsul-
fonyl)tetrazoles, we recently revealed that 5-methylsul-
fonyl-1-(4-nitrophenyl)tetrazole reacts with formalde-
hyde in the presence of triethylamine under microwave
activation to give 5-methylsulfonylmethoxy-1-(4-nitro-
phenyl)tetrazole [5]. We now report that this reaction
is general, and other 5-alkylsulfonyl-1-(4-nitrophenyl)
tetrazoles give rise to the corresponding alkylsulfonyl-
methoxy derivatives as well (Scheme 3).
5-Alkylsulfonyl-1-aryltetrazoles were synthesized
previously by oxidation of 5-alkylsulfanyl-1-aryltetra-
zoles with potassium permanganate in the two-phase
system methylene chloride–aqueous acetic acid using
tetrabutylammonium bromide as phase-transfer cata-
lyst [1]. However, this procedure requires subsequent
utilization of manganese dioxide, and the reaction time
is considerably long. The use of hydrogen peroxide as
oxidant under microwave irradiation is free from the
above disadvantages. The reaction time shortens from
10–12 to 2–7 h, and there is no need of utilizing by-
products, while the target 5-alkylsulfonyltetrazoles Ia–
Ic are formed in 76–90% yield (Scheme 1).
Scheme 2.
4-O2NC6H4
SO2R
N
HNO3, H2SO4
Ia–Ic
N
N
N
IIa–IIc
R = Me (a), Et (b), Pr (c).
We cannot still propose a rigorous mechanism of
the process. Presumably, compounds IIIa–IIIc are
formed via addition of formaldehyde molecule to the
tetrazole carbon atom to give a dipolar intermediate
and subsequent migration of the alkylsulfonyl group to
the positively charged center of that dipole. It should
Scheme 1.
Ph
SR
Ph
SO2R
H2O2, AcOH, MW
N
N
N
N
N
N
N
N
Ia–Ic
R = Me (a), Et (b), Pr (c).
Scheme 3.
4-O2NC6H4
OCH2SO2R
CH2O, Et3N
MeN, MW
By treatment of compounds Ia–Ic with a mixture of
nitric and sulfuric acids we obtained 5-alkylsulfonyl-1-
(4-nitrophenyl)tetrazoles IIa–IIc (Scheme 2).
N
IIa–IIc
N
N
N
IIIa–IIIc
We previously showed [1–3] that 1-aryl-5-(methyl-
sulfonyl)tetrazoles are highly reactive toward various
R = Me (a), Et (b), Pr (c).
475

EGOROVA et al.
476
be noted that such transformations in the tetrazole
series were not described previously.
to slowly warm up to 18–20°C, stirred for 2 h, and
poured onto 200 g of finely crushed ice. The precip-
itate was filtered off, washed with water (3×50 ml),
and dried in air. Yield 2.4 g (89%), mp 155–156°C
(from acetonitrile) [2]. IR spectrum, ν, cm–1: 954,
1010, 1060, 1103, 1118, 1164, 1231, 1270, 1299, 1313,
1326, 1339, 1380, 1416, 1499, 1527, 1539, 1596, 1618,
The structure of tetrazoles IIIa–IIIc was proved by
the analytical data, IR and NMR spectra, and X-ray
analysis [5].
5-Methylsulfonyl-1-phenyltetrazole (Ia). A Pyrex
reactor was charged with a solution of 15 g (78 mmol)
of 5-methylsulfanyl-1-phenyltetrazole in 150 ml of
glacial acetic acid, 30 ml of 35% hydrogen peroxide
was added at 20°C, and the mixture was stirred for 2 h
under microwave irradiation (30 W, 70°C). The mix-
ture was cooled to 18°C and diluted with 100 ml of ice
water, and the precipitate was filtered off, washed with
water (3×20 ml), and dried in air. Yield 15.7 g (90%),
mp 83–84°C (from ethanol) [1]. IR spectrum, ν, cm–1:
981, 1017, 1054, 1074, 1108, 1154, 1157, 1173, 1233,
1270, 1295, 1322, 1335, 1350, 1403, 1428, 1458, 1593,
1
2300, 2870, 2931, 3009, 3046, 3081, 3122. H NMR
spectrum, δ, ppm: 3.70 s (3H, CH3), 8.04–8.68 d (2H,
Harom), 8.47–8.52 d (2H, Harom). Found, %: C 35.71;
H 2.47; N 26.20; S 11.96. C8H7N5O4S. Calculated, %:
C 35.69; H 2.60; N 26.02; S 11.90.
5-Alkylsulfonyl-1-(4-nitrophenyl)tetrazoles IIb and
IIc were synthesized in a similar way.
5-Ethylsulfonyl-1-(4-nitrophenyl)tetrazole (IIb).
Yield 86%, mp 135–136°C (from DMF–propan-2-ol,
1:3). IR spectrum, ν, cm–1: 974, 980, 1009, 1033,
1039, 1056, 1113, 1155, 1159, 1177, 1235, 1254, 1268,
1282, 1299, 1314, 1326, 1344, 1379, 1399, 1428, 1447,
1498, 1530, 1596, 1612, 1709, 1821, 1954, 2793, 2866,
2939, 2949, 2974, 3002, 3016, 3060, 3082, 3114.
1H NMR spectrum, δ, ppm: 1.29–1.33 t (3H, CH3),
3.76–3.81 m (2H, CH2), 8.07–8.09 d (2H, Harom), 8.47–
8.49 d (2H, Harom). Found, %: C 38.24; H 3.14;
N 24.75; S 11.25. C9H9N5O4S. Calculated, %: C 38.16;
H 3.18; N 24.73; S 11.31.
1
2929, 3015. H NMR spectrum, δ, ppm: 3.67 s (3H,
CH3), 7.62–7.76 m (5H, Harom). Found, %: C 42.84;
H 3.40; N 24.97; S 14.46. C8H8N4O2S. Calculated, %:
C 42.86; H 3.57; N 25.00; S 14.29.
5-Alkylsulfonyl-1-phenyltetrazoles Ib and Ic were
synthesized in a similar way.
5-Ethylsulfonyl-1-phenyltetrazole (Ib). Yield
86%, mp 69–71°C (from ethanol). IR spectrum, ν,
cm–1: 981, 1017, 1040, 1058, 1075, 1113, 1151, 1241,
1267, 1285, 1328, 1341, 1386, 1395, 1411, 1422, 1458,
1497, 1593, 2890, 2928, 2974, 3063, 3078, 3105.
1H NMR spectrum, δ, ppm: 1.27–1.31 t (3H, CH3),
3.73–3.78 m (2H, CH2), 7.62–7.75 m (5H, Harom).
Found, %: C 45.29; H 4.21; N 23.57; S 13.68.
C9H10N4O2S. Calculated, %: C 45.37; H 4.20; N 23.53;
S 13.45.
1-(4-Nitrophenyl)-5-propylsulfonyltetrazole
(IIc). Yield 98%, mp 95–96°C (from ethyl acetate). IR
spectrum, ν, cm–1: 1009, 1052, 1086, 1107, 1148,
1260, 1292, 1298, 1312, 1342, 1378, 1401, 1458, 1494,
1529, 1533, 1595, 1614, 2884, 2924, 2976, 3063, 3077.
1H NMR spectrum, δ, ppm: 0.98–1.00 t (3H, CH3),
1.78–1.80 m (2H, CH2), 3.71–3.79 m (2H, CH2), 8.06–
8.08 d (2H, Harom), 8.47–8.49 d (2H, Harom). Found, %:
C 40.23; H 3.78; N 23.39; S 10.79. C10H11N5O4S. Cal-
culated, %: C 40.40; H 3.70; N 23.57; S 10.77.
1-Phenyl 5-propylsulfonyltetrazole (Ic). Yield
76%, mp 48–49°C (from ethanol). IR spectrum, ν,
cm–1: 920, 1015, 1050, 1077, 1085, 1103, 1155, 1176,
1210, 1249, 1299, 1338, 1401, 1454, 1458, 1465, 1470,
1497, 1594, 2876, 2904, 2940, 2971, 2978, 3062.
1H NMR spectrum, δ, ppm: 0.94–0.98 t (3H, CH3),
1.71–1.81 m (2H, CH2), 3.71–3.75 m (2H, CH2), 7.62–
7.74 m (5H, Harom). Found, %: C 47.68; H 4.81;
N 22.22; S 12.64. C10H12N4O2S. Calculated, %:
C 47.62; H 4.76; N 22.22; S 12.70.
5-Methylsulfonylmethoxy-1-(4-nitrophenyl)-
tetrazole (IIIa). 5-Methylsulfonyl-1-(4-nitrophenyl)-
tetrazole (IIa), 2.0 g (7 mmol), was dissolved in 25 ml
of acetonitrile, 1 ml of a 37.4% formaldehyde solution
and 1.06 g (10.5 mmol) of triethylamine were added,
and the mixture was stirred for 1.5 h under microwave
irradiation (25 W, 40°C). The mixture was then diluted
with 50 ml of ethanol, and the precipitate was filtered
off and dried in air. Yield 1.98 g (89%), mp 149–150°C
(from acetonitrile). IR spectrum, ν, cm–1: 943, 975,
1097, 1109, 1133, 1151, 1297, 1312, 1323, 1340, 1352,
1368, 1404, 1416, 1445, 1460, 1507, 1522, 1560, 1599,
5-Methylsulfonyl-1-(4-nitrophenyl)tetrazole
(IIa). A solution of 2.25 g (10 mmol) of 5-methylsul-
fonyl-1-phenyltetrazole in 10 ml of 94% sulfuric acid
was cooled to 5°C, and 3 ml of 98% nitric acid was
added dropwise under stirring, maintaining the tem-
perature below 10°C. An additional 5 ml of 94%
sulfuric acid was added, and the mixture was allowed
1
1619, 2925, 2946, 3019, 3110, 3132, 3450. H NMR
spectrum, δ, ppm: 3.19 s (3H, CH3), 5.79 s (2H, CH2),
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 3 2007

SYNTHESIS AND CHEMICAL PROPERTIES OF 5-ALKYLSULFONYL-...
477
8.03–8.06 d (2H, Harom), 8.48–8.50 d (2H, Harom).
Found, %: C 36.10; H 2.79; N 23.38; S 10.68.
C9H9N5O5S. Calculated, %: C 36.12; H 3.01; N 23.41;
S 10.70.
S 10.05. C11H13N5O5S. Calculated, %: C 40.37; H 3.98;
N 21.40; S 9.78.
The IR spectra were measured on a Shimadzu
FTIR-8400S spectrometer from samples prepared as
1
KBr pellets. The H NMR spectra were recorded on
5-Alkylsulfonylmethoxy-1-(4-nitrophenyl)tetra-
a Bruker AC-400 instrument from solutions in
DMSO-d6. The elemental compositions were deter-
mined on a LECO CHNS(O)-932 analyzer. Micro-
wave-assisted reactions were performed in a Milestone
P/N 44072 reactor. The purity of the products was
checked by TLC on Silufol plates using ethyl acetate–
carbon tetrachloride (2:3) as eluent.
zoles IIIb and IIIc were synthesized in a similar way.
5-Ethylsulfonylmethoxy-1-(4-nitrophenyl)tetra-
zole (IIIb). Yield 95%, mp 131–132°C (from ethyl
acetate). IR spectrum, ν, cm–1: 944, 1024, 1047, 1091,
1099, 1110, 1129, 1138, 1275, 1299, 1310, 1326, 1342,
1351, 1417, 1454, 1463, 1507, 1527, 1562, 1597, 1614,
1
2926, 2964, 3027, 3104. H NMR spectrum, δ, ppm:
This study was performed under financial support
by the Russian Foundation for Basic Research (project
no. 06-03-32286a).
1.88–1.92 t (3H, CH3), 3.76–3.81 m (2H, CH2), 6.16 s
(2H, CH2), 8.55–8.57 d (2H, Harom), 8.99–9.01 d (2H,
Harom). Found, %: C 38.50; H 3.39; N 22.60; S 10.56.
C10H11N5O5S. Calculated, %: C 38.34; H 3.51;
N 22.36; S 10.22.
REFERENCES
1-(4-Nitrophenyl)-5-propylsulfonylmethoxy-
tetrazole (IIIc). Yield 94%, mp 100–102°C (from
ethanol–acetonitrile, 5:1). IR spectrum, ν, cm–1: 955,
978, 1009, 1024, 1044, 1092, 1100, 1110, 1124, 1138,
1181, 1215, 1243, 1257, 1293, 1307, 1314, 1343, 1350,
1369, 1384, 1418, 1458, 1504, 1523, 1532, 1558, 1599,
1617, 1727, 1753, 2880, 2936, 2954, 2974, 3024, 3105,
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Chem., 1996, vol. 32, p. 1194.
2. Koreneva, A.P. and Koldobskii, G.I., Russ. J. Org. Chem.,
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p. 469.
1
3126. H NMR spectrum, δ, ppm: 1.56–1.60 t (3H,
CH3), 2.37–2.42 m (2H, CH2), 3.73–3.77 m (2H, CH2),
6.14 c (2H, CH2), 8.54–8.57 d (2H, Harom), 8.98–9.01 d
(2H, Harom). Found, %: C 40.42; H 3.80; N 21.64;
5. Lyakhov, A.S., Egorova, N.G., Artamonova, T.V., Gapo-
nik, P.N., and Koldobskii, G.I., Acta Crystallogr., Sect. E,
2006, vol. 62, p. o903.
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