INFLUENCE OF OXIDATION CONDITIONS
877
3
Nacht HMK instrument. Thin-layer chromatography
was performed on Sorbfil PTSKh-PA-UV plates; eluent
ethanol–25% ammonia, 7 : 3; detection in UV light.
spectrum, δ, ppm: 0.88 d [6H, CH CH(CH ) , J
HH
=
2
3 2
6.8 Hz], 2.13 m [1H, CH CH(CH ) ], 2.72 d [2H,
2
3 2
3
CH
CH(CH
)
, JHH = 7.2 Hz], 4.48 br.s (2H, COOH,
2
3
2
NH).
Sulfuric acid (Vekton, State Standard 14262-78,
OSCh 11-5, weight fraction of the main substance
2-tert-Butylimidazole-4,5-dicarboxylic acid (2g).
Yield 52%, mp 263–264°С (mp 263–264°С [19]). Н
3
1
9
8.3%, d 1.84 g/cm ) and hydrogen peroxide (Vekton,
State Standard 177-88, Extra, weight fraction of the
main substance 33%, d 1.13 g/cm ) were used.
NMR spectrum, δ, ppm: 1.45 s (9H, 3CH ), 4.04 br.s
(2H, COOH, NH).
3
3
2
-Alkyl(phenyl)benzimidazoles 1a–1i were pre-
2-n-Pentylimidazole-4,5-dicarboxylic acid (2h).
Yield 46%, mp 258–259°С (mp 260°С [20]). Н NMR
1
pared by the procedures in [16, 17].
spectrum, δ, ppm: 0.90 t (3H, CH CH CH CH CH ,
2
2
2
2
3
Synthesis of 2-alkylimidazole-4,5-dicarboxylic acids
a–2i (general procedure). To a stirred solution of
0.0 mmol of compound 1a–1i in 10 mL of conc.
3
JHH = 7.2 Hz), 1.26 m (2H, CH CH CH CH CH ), 1.32
2
2
2
2
3
2
1
m
(2H, CH CH CH CH CH ), 1.73
m
(2H,
2
2
2
2
3
CH CH CH CH CH ), 2.84 t (2H, CH CH CH CH CH ,
2
2
2
2
3
2
2
2
2
3
H SO we added dropwise 10 mL (0.11 mmol) of 33%
2
4
3
JHH = 7.6 Hz), 4.56 br.s (2H, COOH, NH).
2-Phenylimidazole-4,5-dicarboxylic acid (2i).
Yield 47%, mp 269–270°С (mp 265°С [4]). Н NMR
spectrum, δ, ppm: 5.07 br.s (2H, COOH, NH), 7.57 m
aqueous hydrogen peroxide at 100–105°С. The
mixture was stirred for 0.5 h at 120°С, let to cool
down, and poured in water. The pH of the solution was
adjusted to ~2 with sodium carbonate, and the
precipitate of 2-alkylimidazole-4,5-dicarboxylic acid
1
3
(3Н ), 8.18 d (2Н , J = 6.8 Hz).
Ar
Ar
HH
2
a–2i was filtered off and recrystallized from water.
REFERENCES
2
-Methylimidazole-4,5-dicarboxylic acid (2a).
1
Yield 82%, mp 271–272°С (mp 272–273°С [9]). Н
NMR spectrum, δ, ppm: 2.51 s (3H, CH ), 4.58 br.s
1. Babu, K.S., Reddy, M.S., Tagore, A.R., Reddy, G.S.,
Sebastian, S., Varma, M.S., Venkateswarlu, G.,
Bhattacharya, A., Reddy, P.P., and Anand, R.V., Synth.
Commun., 2009, vol. 39, no. 2, p. 291. doi
3
(
2H, COOH, NH).
2
-Ethylimidazole-4,5-dicarboxylic acid (2b). Yield
1
0.1080/00397910802372558
1
7
8%, mp 260–261°С (mp 259–260°С [9]). Н NMR
2. Efremov, O.M., Aleksandrova, I.Ya., Kulikov, S.V.,
Losev, N.A., and Piotrovskii, L.B., Eksp. Klin.
Farmakol., 2005, vol. 68, no. 1, p. 7.
3
spectrum, δ, ppm: 1.29 t (3H, CH CH , J = 7.6 Hz),
2
2
3
HH
3
.88 q (2H, CH CH , J = 7.6 Hz), 5.93 br.s (2H,
2 3 HH
COOH, NH).
3. Piotrovskii, L.B., Lishko, P.V., Maksimyuk, A.P.,
Aleksandrova, I.Ya., and Kryshtal, O.A., Neurosci.
Behav. Physiol., 2000, vol. 30, no. 5, p. 553. doi
2
-Propylimidazole-4,5-dicarboxylic acid (2c).
1
Yield 72%, mp 256–257°С (mp 255–256°С [9]). Н
NMR spectrum, δ, ppm: 0.91 t (3H, CH CH CH ,
1
0.1007/BF02462614
2
2
3
4. Lebedev, A.V., Lebedeva, A.B., Sheludyakov, V.D.,
Kovaleva, E.A., Ustinova, O.L., and Shatunov, V.V.,
Russ. J. Gen. Chem., 2007, vol. 77, no. 5, p. 949. doi
10.1134/S1070363207050234
3
JHH = 7.6 Hz), 1.75 m (2H, CH CH CH ), 2.84 t (2H,
2
2
3
3
CH CH CH , J = 7.6 Hz), 5.20 br.s (2H, COOH,
2
2
3
HH
NH).
5
. Huang, H., Huang, L., and Zhang, X., CN Patent
2
-Isopropylimidazole-4,5-dicarboxylic acid (2d).
1
1
02070533, 2011; Chem. Abstr., 2011, CAN
54:615171
1
Yield 57%, mp 262–263°С (mp 269°С [4]). Н NMR
spectrum, δ, ppm: 1.36 d (6H, CH , J = 6.8 Hz),
3
3
HH
6
. Lu, W.-G., Gu, J.-Z., Jiang, L., Tan, M.-Y., and Lu, T.-B.,
3
.32 m (1H, CH), 4.40 br.s (2H, COOH, NH).
Cryst. Growth Design, 2008, vol. 8, no. 1, p. 192. doi
1
0.1021/cg060778h
2
-n-Butylimidazole-4,5-dicarboxylic acid (2e).
1
7. Ivanov, V.A., Zh. Prikl. Khim., 1979, vol. 52, no. 7,
Yield 53%, mp 259–261°С (mp 261–263°С [18]). Н
NMR spectrum, δ, ppm: 0.92 t (3H, CH CH CH CH ,
JHH = 7.6 Hz), 1.31 m (2H, CH CH CH CH ), 1.71 m
2H, CH CH CH CH ), 2.86 t (2H, CH CH CH CH ,
JHH = 7.6 Hz), 4.56 br.s (2H, COOH, NH).
p. 1655.
2
2
2
3
3
8. Sun, T., Ma, J.-P., Huang, R.-Q., and Dong, Y.-B., Acta
Crystallogr., Part E, 2006, vol. 62, no. 7, p. o2751. doi
10.1107/S1600536806020356
. Schubert, H., Hoffmann, S., Lehmann, G., Barthold, I.,
Meichsner, H., and Polster, H.-E., Z. Chem., 1975,
vol. 15, p. 481. doi 10.1002/zfch.19750151209
2
2
2
3
(
2 2 2 3 2 2 2 3
3
9
2
-Isobutylimidazole-4,5-dicarboxylic acid (2f).
1
Yield 57%, mp 256–257°С (mp 257°С [4]). Н NMR
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 88 No. 5 2018