Molecules 2015, 20
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3-Methyl-4-[(phenoxycarbonyl)amino]benzenesulfonic acid (6) Yield: 0.60 g (98%). White powder.
1H-NMR (300 MHz, DMSO-d6) δ, ppm, 9.41 (s, 1H), 7.47 (s, 1H), 7.42–7.35 (m, 4H), 7.23 (t, J = 6.0 Hz,
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1H), 7.20 (d, J = 6.0 Hz, 2H), 2.29 (s, 3H); C-NMR (300 MHz, DMSO-d6) δ, ppm, 152.53, 150.76,
144.87, 135.99, 130.93, 129.30, 127.65, 125.19, 124.20, 123.50, 121.75, 17.73. Elemental analysis for:
C14H13NO5S Calc.: C, 54.72; H, 4.26. Found: C, 54.83; H, 4.18. ESI-MS: m/z = 307.
3-Methyl-4-{[(4-methylphenoxy)carbonyl]amino}benzenesulfonic acid (7) Yield: 0.60 g (94%). Brown
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powder. H-NMR (300 MHz, DMSO-d6) δ, ppm, 9.37 (s, 1H), 7.48 (s, 1H), 7.43 (d, J = 8.4 Hz, 1H),
7.37 (d, J = 8.4 Hz, 1H), 7.21 (d, J = 8.4 Hz, 2H), 7.08 (d, J = 8.4 Hz, 2H), 2.31 (s, 3H), 2.28 (s, 3H);
13C-NMR (300 MHz, DMSO-d6) δ, ppm, 152.62, 148.50, 144.96, 135.92, 134.24, 130.76, 129.58,
127.58, 123.56, 123.43, 121.43, 20.26, 17.69. Elemental analysis for: C15H15NO5S Calc.: C, 56.06; H,
4.70. Found: C, 55.87; H, 4.58. ESI-MS: m/z = 321.
3-Methyl-4-{[(naphthalen-1-yloxy)carbonyl]amino}benzenesulfonic acid (8) Yield: 0.68 g (95%).
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Brown powder. H-NMR (300 MHz, DMSO-d6) δ, ppm, 9.72 (s, 1H), 8.03–7.98 (m, 2H), 7.84 (d,
J = 8.0 Hz, 1H), 7.64–7.52 (m, 4H), 7.46–7.40 (m, 3H), 2.36 (s, 3H); 13C-NMR (300 MHz, DMSO-d6)
δ, ppm, 152.57, 146.30, 145.14, 135.83, 134.04, 130.99, 127.83, 127.63, 126.99, 126.48, 126.40,
125.63, 125.32, 124.07, 123.50, 120.91, 118.47, 17.74. Elemental analysis for: C18H15NO5S Calc.: C,
60.49; H, 4.23. Found: C, 60.37; H, 4.48. ESI-MS: m/z = 357.
4-[(Methoxycarbonyl)amino]-3-methylbenzenesulfonic acid (9) Yield: 0.48 g (97%). Brown powder.
1H-NMR (300 MHz, DMSO-d6) δ, ppm, 8.80 (s, 1H), 7.42 (s, 1H), 7.38 (d, J = 7.5 Hz, 1H), 7.30 (d,
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J = 7.5 Hz, 1H), 3.64 (s, 3H), 2.19 (s, 3H); C-NMR (300 MHz, DMSO-d6) δ, ppm, 154.47, 144.23,
136.26, 130.17, 127.31, 123.20, 123.10, 51.56, 17.68. Elemental analysis for: C9H11NO5S Calc.: C, 44.08;
H, 4.52. Found: C, 44.16; H, 4.69. ESI-MS: m/z = 245.
3-Methyl-4-[(propoxycarbonyl)amino]benzenesulfonic acid (10) Yield: 0.52 g (96%). Brown powder.
1H-NMR (300 MHz, DMSO-d6) δ, ppm, 8.78 (s, 1H), 7.46 (s, 1H), 7.42 (d, J = 8.4 Hz, 1H), 7.32 (d,
J = 8.4 Hz, 1H), 4.01 (t, J = 6.6 Hz, 2H), 2.20 (s, 3H), 1.66–1.57 (m, 2H), 0.91 (t, J = 7.4 Hz, 3H);
13C-NMR (300 MHz, DMSO-d6) δ, ppm, 154.52, 143.90, 136.92, 130.63, 127.64, 124.35, 123.51,
65.85, 22.02, 17.83, 10.30. Elemental analysis for: C11H15NO5S Calc.: C, 48.34; H, 5.53. Found: C,
48.13; H, 5.36. ESI-MS: m/z = 273.
4. Conclusions
We have developed a very simple, inexpensive, nontoxic, and environmentally friendly method for
the preparation of carbamates containing sulfonic groups. The presence of the SO3H group in all
synthesized carbamates ensures their good water solubility as their respective salts and thus their
application as tracers in geo-reservoirs. In particular, there is not much information related to the
synthesis of readily water-soluble carbamates. We strongly feel that this study will find numerous
applications even beyond tracers for geothermal applications.