Alkylation of SH-Heterocycles with Diethyl Phosphite Using Tetrachloroethylene as an Efficient Solvent 657
(m, 1H, HAr), 7.75–7.73 (m, 1H, HAr), 7.42–7.38 (m,
4-(Ethylthio)-N-(1,2,2-trichlorovinyl)aniline (2g).
Yellow liquid, yield: 76% (ethyl acetate/petroleum
ether = 1/15); 1H NMR (400 MHz, CDCl3): δ =
7.33–7.32 (m, 2H, HAr), 6.58–6.55 (m, 2H, HAr), 3.96
1H, HAr), 7.29–7.25 (m, 1H, HAr), 3.38–3.32 (m, 2H,
CH CH3), 1.51–1.45 (m, 3H, CH2CH ); 13C NMR
2
3
(100 MHz, CDCl3): δ = 166.9, 153.3, 135.1, 125.9,
124.0, 121.4, 120.8, 27.8, 14.4. MS: m/z = 195 (M+).
Anal. calcd for C9H9NS2 (195.02): Calcd. C 55.35, H
4.64, N 7.17. Found: C 55.48, H 4.59, N 7.11.
(br, 1H, NH), 3.19–3.15 (m, 2H, CH CH3), 1.30–1.25
2
(m, 3H, CH2CH ). 13C NMR (100 MHz, CDCl3): δ =
3
149.5, 136.4, 133.6, 129.5, 120.8, 118.0, 115.6, 112.9,
38.1, 29.6, 14.6.0. MS: m/z = 281 (M+) (60%), 283
(M + 2) (59%), 285 (M + 4) (24%), 266 (M – Me)
(100%), 268 (M – Me + 2) (98%), 270 (M – Me + 4)
(36%). Anal. calcd for C10H10Cl3NS (280.96): Calcd.
C 42.50, H 3.75, N 3.96, Found: C 42.61, H 6.64, N
4.85.
3-Ethylbenzo[d]thiazole-2(3H)-thione (3d). Col-
orless liquid, yield: 10%(ethyl acetate/petroleum
1
ether = 1/30); H NMR (400 MHz, CDCl3): δ = 7.50
(d, J = 8.0 Hz, 1H, HAr), 7.42 (t, J = 8.0 Hz, 1H, HAr),
7.30 (q, J = 8.0 Hz, 1H, HAr), 7.25 (t, J = 8.0 Hz,
1H, HAr), 4.51 (q, J = 7.6 Hz, 2H, CH CH3), 1.46
2
(t, J = 7.6 Hz, 3H, CH2CH ); 13C NMR (100 MHz,
Experimental Procedure for the Synthesis of Com-
pound 2h. To a solution of 4-aminobenzenethiol
(1g) (1 mmol) and DMAP (0.2 mmol) in toluene (2
mL), diethyl phosphite (2 mmol) was added. After
being stirred for 12 h at 110◦C, the reaction mixture
was concentrated under reduced pressure. Purifica-
tion by chromatography on silica gel using ethyl ac-
etate in petroleum ether (60–90◦C) gave pure sam-
ples of product 2h.
4-(Ethylthio)benzenamine (2h). Brown liquid,
yield: 78% (ethyl acetate/petroleum ether = 1/20);
1H NMR (400 MHz, CDCl3): δ = 7.29–7.28 (m, 2H,
HAr), 6.52–6.48 (m, 2H, HAr), 3.68 (br, 2H, NH), 3.13
3
CDCl3): δ = 188.8, 141.1, 128.0, 126.9, 124.6, 121.4,
112.2, 41.3, 11.8. MS: m/z = 195 (M+). Anal. calcd
for C9H9NS2 (195.02): Calcd. C 55.35, H 4.64, N 7.17.
Found: C 55.29, H 4.67, N 7.11.
2-(Benzofuran-2-yl)-5-(ethylthio)-1,3,4-oxadiazo-
le (2e). Colorless solid, mp 62–64◦C, yield: 73%
(ethyl acetate/petroleum ether = 1/15); 1H NMR
(400 MHz, CDCl3): δ = 7.82 (d, J = 0.8 Hz, 1H,
Hfuran), 7.70–7.34 (m, 4H, HAr), 3.36 (q, J = 7.6 Hz,,
2H, CH CH3), 1.58–1.52 (m, 3H, CH2CH ); 13C NMR
2
3
(100 MHz, CDCl3): δ = 154.3, 130.0, 124.7, 124.0,
122.2, 113.5, 112.0, 109.8, 108.8, 27.1, 14.6. MS:
m/z = 246 (M+). Anal. calcd for C12H10NO2S (246.05):
Calcd. C 58.52, H 4.09, N 11.37. Found: C 58.64, H
4.04, N 11.43.
(q, J = 7.2 Hz, 2H, CH CH3), 1.23 (d, J = 7.2 Hz,
2
3H, CH2CH ); 13C NMR (100 MHz, CDCl3): δ = 148.8,
3
134.4, 123.9, 115.4, 38.1, 14.6.0. MS: m/z = 153 (M+).
Anal. calcd for C8H11NS (153.06): Calcd. C 62.70, H
7.24, N 9.14, Found: C 62.81, H 7.29, N 9.05.
5-(Benzofuran-2-yl)-3-ethyl-1,3,4-oxadiazole-2
(3H)-thione (3e). Colorless solid, mp 122–124◦C,
yield: 11% (ethyl acetate/petroleum ether = 1/15);
1H NMR (400 MHz, CDCl3): δ = 7.85 (d, J =
0.8 Hz, 1H, Hfuran), 7.72–7.29 (m, 4H, HAr), 4.26–4.20
(m, 2H, CH CH3), 1.57–1.48 (m, 3H, CH2CH ); 13C
NMR (100 MHz, CDCl3): δ = 175.3, 155.8, 152.4,
140.1, 130.6, 127.7, 126.8, 124.3, 113.5, 112.0,
29.6, 12.5. MS: m/z = 246 (M+). Anal. calcd for
C12H10NO2S (246.05): Calcd. C 58.52, H 4.09, N
11.37. Found: C 58.62, H 4.13, N 11.45.
REFERENCES
[1] (a) Kosolapoff, G. M.; Maier, L. (Eds.). Organic Phos-
phorus Compounds; Wiley-Interscience: New York,
1976; (b) Corbridge, D. E. C. Phosphorus: An Out-
line of Its Chemistry, Biochemistry and Uses, 5th
ed.; Elsevier: Amsterdam, 1995; (c) Swaminathan, S.;
Narayanan, K. V. Chem Rev 1971, 71, 429; (d) Bhat-
tacharya, A. K.; Thyagarajan, G. Chem Rev 1981, 81,
415.
[2] For elected examples of reaction of imines and ke-
timines, see: (a) Merino, P.; Marque´s-Lo´pez, E.;
Herrera, R. P. Adv Synth Catal 2008, 350, 1195;
(b) Ordo´n´ez, M.; Rojas-Cabrera, H.; Cativiela, C.
Tetrahedron 2009, 65, 17; (c) Nakamura, S.; Hayashi,
M.; Hiramatsu, Y.; Shibata, N.; Funahashi, Y.;
2
3
O,O-Diethyl S-p-tolyl phosphorothioate (2f).
Yellow liquid, yield: 86% (ethyl acetate/petroleum
ether
=
1/15); 1H NMR (400 MHz, CDCl3):
Toru, T.
J Am Chem Soc 2009, 131, 18240;
δ = 7.43 (dd, J = 0.8 Hz, J = 8.0 Hz, 2H, HAr), 7.15
(c) Gambecka, J.; Kafarski, P. Mini-Rev Med Chem
2001, 1, 133.
(d, J = 8.0 Hz, 2H, HAr), 4.22–4.13 (m, 4H,
[3] For selected examples of addition to carbonyl com-
pounds, see: (a) Wiemer, D. F. Tetrahedron 1997,
53, 16609; (b) Gro¨ger, H.; Hammer, B. Chem Eur
J 2000, 6, 943; (c) Rath, N. P.; Spilling, C. D. Tetrahe-
dron Lett 1994, 35, 227; (d) Qian, C.; Huang, T.; Zhu,
C.; Sun, J. J Chem Soc, Perkin Trans 1 1998, 2097;
OCH CH3), 2.34 (s, 3H, CH3), 1.35–1.23 (m, 3H,
2
CH2CH ). 13C NMR (100 MHz, CDCl3): δ = 139.2,
3
134.5, 130.1, 122.7, 63.9, 21.1, 16.0. MS: m/z = 260
(M+). Anal. calcd for C11H17PO3S (260.05): Calcd. C
50.76, H 6.58, Found: C 50.88, H 6.53.
Heteroatom Chemistry DOI 10.1002/hc