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A. K. Verma et al.
and the mixture was stirred at 25ꢀC for 1–30 min. The
completion of the reactions was monitored by TLC. The
product formed in the one-phase system, was extracted
with 2ꢁ25 cm3 ether. The combined organic layer was
separated, dried (Na2SO4), and evaporated under reduced
pressure to afford the addition products. The aqueous layer
consisting of the IL was subjected to distillation at 80ꢀC
and 5 mm Hg for 2 h to remove water, leaving behind
the IL, which was further recycled. The conversion and
the yield were not reduced after being reused 10 times. The
products thus isolated, were pure and recrystallized from
EtOAc:petroleum ether (single spot on TLC).
3.05 (t, J ¼ 4.6Hz, 4H), 2.76 (t, J ¼ 6.7 Hz, 2H), 2.65 (t, J ¼
4.5 Hz, 4H), 2.56 (t, J ¼ 6.7 Hz, 2H) ppm; 13C NMR (75 MHz,
CDCl3): ꢂ ¼ 144.1, 140.2, 118.6, 116.0, 53.2, 52.7, 50.7, 30.6,
15.7ppm; LC-MS: m=z (%) ¼ 230.15 (100, M þ 1).
3-[4-[(Benzo[1,3]dioxol-5-yl)methyl]piperazin-1-yl]propio-
nitrile (1i, C15H19N3O2)
Mustard colour oil; 1H NMR (300MHz, CDCl3): ꢂ ¼ 6.83 (s,
1H), 6.73 (s, 2H), 5.93 (s, 2H), 3.40 (s, 2H), 2.68 (t, J ¼
6.98Hz, 2H), 2.51–2.46 (m, 10H) ppm; 13C NMR (75 MHz,
CDCl3): ꢂ ¼ 151.2, 148.5, 138.0, 122.0, 109.3, 107.7, 100.7,
62.4, 53.1, 52.5, 31.7, 15. 6 ppm; LC-MS: m=z (%) ¼ 273.13
(100, M þ 1).
General procedure of the thia-Michael reaction
A solution of 1 mmol thiols and 1.2 mmol ꢀ,ꢁ-unsaturated
nitriles and carbonyl compounds in 2 cm3 TEAA was stirred
at 25ꢀC for 1 min. The completions of the reactions were
monitored by TLC. The product formed in one phase sys-
tem was diluted with 20 cm3 H2O and extracted with
2ꢁ25 cm3 ether. The combined organic layer was separat-
ed, dried (Na2SO4), and evaporated under reduced pressure
to afford the addition products. The aqueous layer consist-
ing of the IL was subjected to distillation at 80ꢀC and
5 mmHg for 2 h to remove water, leaving behind the IL,
which was further recycled. The conversion and the yield
were not reduced after being reused 10 times. The products,
thus isolated, were pure and recrystallized from EtOAc:
petroleum ether (single spot on TLC).
3-(Octylsulfanyl)cyclohexanone (2d, C14H26OS)
1
Colorless oil; H NMR (300 MHz, CDCl3): ꢂ ¼ 0.89 (t, J ¼
6.6 Hz, 3H), 1.26–1.36 (m, 10H), 1.51–1.59 (m, 2H), 1.66–
1.75 (m, 2H), 2.11–2.17 (m, 2H), 2.33–2.35 (m, 4H), 2.52
(t, J ¼ 7.35 Hz, 2H), 3.05–3.57 (m, 1H) ppm; 13C NMR
(75 MHz, CDCl3): ꢂ ¼ 14.06, 22.61, 24.26, 25.65, 28.93,
29.14, 29.69, 30.53, 31.65, 31.76, 40.95, 42.74, 48.25,
209.02 ppm; LC-MS : m=z (%) ¼ 242.17 (100, M þ 1).
3-(p-Tolylsulfanyl)cyclohexanone (2f, C13H16OS)
Colorless oil; 1H NMR (300MHz, CDCl3): ꢂ ¼ 1.61–1.77 (m,
2H), 2.01–2.69 (m, 9H), 2.63–3.36 (m, 1H), 7.09–7.14 (m,
2H), 7.32–7.39 (m, 2H) ppm; 13C NMR (75 MHz, CDCl3):
ꢂ ¼ 21.1, 24.1, 31.3, 40.8, 46.5, 47.8, 128.5, 129.1, 129.8,
133.9, 138.2, 208.9 ppm; LC-MS: m=z(%) ¼ 220.1 (100, M þ 1).
3-(4-Phenylpiperazin-1-yl)cyclohexanone (1e, C16H22N2O)
Colorless oil: 1H NMR (300 MHz, CDCl3): ꢂ ¼ 7.29 (m, 2H),
7.92 (m, 3H), 3.20 (t, J ¼ 4.95Hz, 4H), 2.8–2.6 (m, 6H), 2.5–
2.3 (m, 3H), 2.2–2.0 (m, 2H), 1.76–1.72 (m, 2H) ppm; 13C
NMR (75 MHz, CDCl3): ꢂ ¼ 210.5, 151.2, 129.1, 119.8,
116.1, 63.2, 49.5, 48.9, 44.4, 41.2, 28.1, 22.4ppm; LC-MS:
m=z (%) ¼ 258.17 (100, M þ 1).
3-(2-Methoxyphenylsulfanyl)butyraldehyde (2j, C11H14O2S)
Colorless oil; 1H NMR (300MHz, CDCl3): ꢂ ¼ 2.52–2.72 (m,
3H), 3.89 (s, 3H), 6.82–6.95 (m, 3H), 7.24–7.34 (m, 1H)
ppm; 13C NMR (75 MHz, CDCl3): ꢂ ¼ 21.0, 35.8, 50.2, 55.7,
110.9, 121.0, 121.3, 127.6, 129.4, 159.1, 200.9ppm; LC-MS:
m=z (%) ¼ 210.1 (100, M þ 1).
3-[4-(4-Chlorophenyl)piperazin-1-yl]propionitrile
(1f, C13H16ClN3)
3-p-Tolylsulfanyl-butyraldehyde (2k, C11H14OS)
Colorless oil; 1H NMR (300 MHz, CDCl3): ꢂ ¼ 1.35–1.37 (d,
J ¼ 6.90 Hz, 3H), 2.42 (s, 3H), 2.56–2.75 (m, 2H), 3.64–
3.75 (m, 1H), 7.12–7.41 (m, 4H), 9.75 (s, 1H) ppm; 13C
NMR (75 MHz, CDCl3): ꢂ ¼ 20.8, 21.0, 36.9, 50.2, 126.5,
126.7, 127.5, 130.5, 132.6, 133.3, 140.2, 200.4 ppm; LC-
MS: m=z (%) ¼ 194.0 (100, M þ 1).
Light yellow solid, mp 98–100ꢀC; 1H NMR (300MHz,
CDCl3): ꢂ ¼ 7.20 (d, J ¼ 6.9 Hz, 2H), 6.83 (d, J ¼ 6.9 Hz,
2H), 3.17 (t, J ¼ 4.6 Hz, 4H), 2.74 (t, J ¼ 6.9 Hz, 2H), 2.66
(t, J ¼ 4.6 Hz, 4H) 2.55 (t, J ¼ 6.8 Hz, 2H) ppm; 13C NMR
(75 MHz, CDCl3): ꢂ ¼ 149.6, 128.9, 124.7, 118.5, 117.3, 52.5,
49.0, 15.9ppm.
3-(Octylsulfanyl)propionitrile (2l, C11H21NS)
1
3-[4-(4-Nitrophenyl)piperazin-1-yl]propionitrile
(1g, C13H16N4O2)
Colorless oil; H NMR (300 MHz, CDCl3): ꢂ ¼ 0.88 (t, J ¼
6.0 Hz, 3H), 1.27–1.40 (m, 10H), 1.54–1.69 (m, 2H), 2.56–
2.66 (m, 4H), 2.75–2.80 (m, 2H) ppm; 13C NMR (75 MHz,
CDCl3): ꢂ ¼ 14.09, 18.93, 22.42, 22.64, 27.40, 28.55, 29.24,
29.94, 31.81, 32.04, 118.24 ppm; LC-MS: m=z (%) ¼ 199.14
(100, M þ 1).
Yellow solid, mp 92–94ꢀC; 1H NMR (300MHz, CDCl3): ꢂ ¼
8.10 (d, J ¼ 9.06 Hz, 2H), 6.81 (d, J ¼ 9.12 Hz, 2H), 3.44 (d,
J ¼ 4.5 Hz, 4H), 2.77–2.54 (m, 8H) ppm; 13C NMR (75 MHz,
CDCl3): ꢂ ¼ 154.6, 138.5, 125.8, 118.4, 112.7, 53.0, 52.0,
46.8, 16.0ppm.
3-[4-(4-Aminophenyl)piperazin-1-yl]propionitrile
(1h, C13H18N4)
Acknowledgements
Brown solid, mp 92–94ꢀC; 1H NMR (300 MHz, CDCl3): ꢂ ¼
We gratefully acknowledge financial support from Department
of Science and Technology, New Delhi, for this work.
6.80 (d, J ¼ 8.2 Hz, 2H), 6.64 (s, 8.3, 2H), 3.29 (s, br, 2H),