References and Notes
1
Weininger SJ.
Stermitz FR.
Organic Chemistry
Academic Press Inc.;
New York:
1984.
p.653
2
Ho T.-L.
J. Org. Chem.
1977,
42:
3755
3
Nahmed EM.
Jenner G.
Tetrahedron Lett.
1991,
32:
4917
4 Matsuda F, Ogiya N, and Kato T. inventors; Japan Kokai JP75-82025.
; Chem. Abstr. 1975, 83, 205977
5
Kajimoto T.
Tsuji J.
Bull. Chem. Soc. Jpn.
1969,
42:
827
6
Watsnabe Y.
Tsuji Y.
Kondo T.
Takeuchi R.
J. Org. Chem.
1984,
49:
4451
7
Choudary BM.
Kantam ML.
Ranganath KVS.
Rao KK.
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8a Yamashita H, and Takahashi Y. inventors; Japan Kokai JP 49-25255.
; Chem. Abstr. 1974, 83, 9476
8b
Kawahara K.
Yakugaku Zasshi
1957,
77:
959 ; Chem. Abstr., 1957, 52, 15650
9
S
-(5-Acetylamino-2-chloro-4-fluorophenyl)ethane-thioate: To a solution of 2-chloro-4-fluoro-5-nitrobenzene-sulfonyl chloride (0.55 g, 2.0 mmol) in AcOH (5 mL) was added red phosphorus (0.25 g, 8.0 mmol) and I2 (5.0 mg, 0.04 mmol). The mixture was stirred and heated to reflux at 110 °C for 6 h. After cooling to r.t., the mixture was filtered. The filtrate was poured into ice-water and extracted with EtOAc (3 ×10 mL). The extracts were combined and dried over anhyd Na2SO4. After evaporating the solvent 0.49 g (94%) the desired product was obtained; mp 143-145 °C. IR (KBr): 3315, 3143, 3096, 1705, 1676, 1599, 1521, 1472, 1371, 1103, 957, 881, 706 cm-1. 1H NMR (400 MHz, CDCl3): δ = 8.55 (1 H, d, J = 7.6 Hz), 7.43 (1 H, s), 7.28 (1 H, d, J = 10.8 Hz), 2.45 (3 H, s), 2.20 (3 H, s). MS (70 eV): m/z = 261 (M+), 219 (M+ - CH2CO), 177 (219 - CH2CO), 142 (177 - Cl).
10
General Procedure. A 50-mL three-necked flask was charged with 3,4-dichloronitrobenzene (1h, 1.92 g, 10 mmol), red phosphorus (0.62 g, 20 mmol), I2 (0.1 g, 0.4 mmol), and an organic acid (2a-e or 4a, 40 mmol). The mixture was stirred at 140 °C (110 °C for AcOH) for 6 h. After cooling to r.t., the mixture was decanted onto ice-water and extracted with EtOAc (3 ×10 mL). The extracts were combined and dried over anhyd Na2SO4. The solvent was evaporated to give product 3a-e and 5.
3a: Mp 110-113 °C. IR (KBr): 3297, 3181, 1669, 1592, 1528, 1470, 1379, 812 cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.75 (s, 1 H), 7.31-7.38 (m, 3 H), 2.18 (s, 3 H). MS (70 eV): m/z = 203 (M+), 161.
3b: Mp 86-88 °C. IR (KBr): 3304, 3097, 1667, 1588, 1522, 1466, 1380, 815 cm-1. 1 H NMR (400 MHz, CDCl3): δ = 7.77 (s, 1 H), 7.26-7.35 (m, 3 H), 2.39 (q, 2 H, J = 7.2 Hz), 1.24 (t, 3 H, J = 7.2 Hz). MS (70 eV): m/z = 217 (M+), 161.
3c: Mp 69-71 °C. IR (KBr): 3310, 3098, 2961, 1671, 1589, 1522, 1466, 1382, 818 cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.77 (s, 1 H), 7.34-7.38 (m, 3 H), 2.33 (t, 2 H, J = 7.2 Hz), 1.69-1.78 (m, 2 H), 0.98 (t, 3 H, J = 7.2 Hz). MS (70 eV): m/z = 231 (M+), 161.
3d: Oil. IR (KBr): 3309, 2928, 1666, 1590, 1522, 1470, 1382, 815 cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.76 (s, 1 H), 7.57 (s, 1 H), 7.32-7.34 (m, 2 H), 2.34 (t, 2 H, J = 7.2 Hz), 1.68-1.73 (m, 2 H), 1.29-1.34 (m, 6 H), 0.88 (t, 3 H, J = 6.4 Hz). MS (70 eV): m/z = 273 (M+), 161.
3e: Mp 134-136 °C. IR (KBr): 3298, 1652, 1582, 1511, 1381, 813, 714 cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.91 (s, 1 H), 7.84-7.90 (m, 3 H), 7.41-7.60 (m, 5 H). MS (70 eV): m/z = 265 (M+), 105.
5: Mp 182-184 °C. IR (KBr): 3086, 2961, 1729, 1684, 1468, 1365, 1256, 1135, 832, 760 cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.53 (d, 1 H, J = 8.4 Hz), 7.26 (s, 1 H), 6.97 (d, 1 H, J = 8.4 Hz), 2.82 (t, 4 H, J = 6.4 Hz), 2.11 (dd, 2 H, J = 6.4, 6.4 Hz). MS (70 eV): m/z = 257 (M+), 229, 187, 161.
11 Following the same procedure described above, 1h was replaced by nitroarenes 1a-g, and propionic acid (2b) was employed to give 3f-l.
3f: Mp 84-86 °C. IR (KBr): 3255, 1666, 1603, 1541, 750 cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.62-7.64 (m, 2 H), 7.30-7.32 (m, 2 H), 7.21 (s, 1 H), 7.08- 7.12 (m, 1 H), 2.43 (q, 2 H, J = 7.2 Hz), 1.26 (t, 2 H, J = 7.2 Hz). MS (70 eV): m/z = 149 (M+), 93.
3g: Mp 79-81 °C. IR (KBr): 3280, 2935, 1659, 1529, 1457, 782, 720 cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.81 (s, 1 H), 6.85-7.11 (m, 3 H), 2.45 (q, 2 H, J = 7.2 Hz), 2.33 (s, 3 H), 2.29 (s, 3 H), 1.26 (t, 2 H, J = 7.2 Hz). MS (70 eV): m/z = 177 (M+), 121, 106.
3h: Mp 91-93 °C. IR (KBr): 3288, 3032, 1664, 1587, 1526, 1285, 754 cm-1. 1H NMR (400 MHz, CDCl3): δ = 8.40-8.42 (m, 1 H), 7.64 (s, 1 H), 7.36-7.37 (m, 1 H), 7.26 -7.29 (m, 1 H), 7.02-7.05 (m, 1 H), 2.48 (q, 2 H, J = 7.2 Hz), 1.28 (t, 2 H, J = 7.2 Hz). MS (70 eV): m/z = 183 (M+), 148, 127.
3i: Mp 74-75 °C. IR (KBr): 3248, 2977, 1668, 1596, 1532, 1415, 1307, 879, 774 cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.74 (s, 1 H), 7.50-7.52 (m, 1 H), 7.36-7.42 (m, 1 H), 7.20-7.26 (m, 1 H), 7.06-7.08 (m, 1 H), 2.39 (q, 2 H, J = 7.2 Hz), 1.24 (t, 3 H, J = 7.2 Hz). MS (70 eV): m/z = 183 (M+), 127.
3j: Mp 123-124 °C. IR (KBr): 3299, 2976, 1666, 1605, 1542, 1492, 823 cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.48 (d, 2 H, J = 8.0 Hz), 7.28 (d, 2 H, J = 8.0 Hz), 7.14 (s, 1 H), 2.39 (q, 2 H, J = 7.4 Hz), 1.25 (t, 3 H, J = 7.4 Hz). MS (70 eV): m/z = 183 (M+), 127.
3k: Mp 105-107 °C. IR (KBr): 3272, 3089, 1663, 1556, 1507, 1212, 830 cm-1. 1H NMR (400 MHz, CDCl3): δ = 7.47-7.48 (m, 2 H), 7.22 (s, 1 H), 6.99-7.02 (m, 2 H), 2.37 (q, 2 H, J = 7.2 Hz), 1.24 (t, 3 H, J = 7.2 Hz). MS (70 eV): m/z = 167 (M+), 111.
3l: Mp 75-77 °C. IR (KBr): 3270, 2987, 1670, 1532, 1424, 1333, 1121, 820 cm-1. 1H NMR (400 MHz, CDCl3): δ = 8.80 (s, 1 H), 7.72 (s, 1 H), 7.49 (d, 1 H, J = 8.0 Hz), 7.29 (d, 2 H, J = 8.0 Hz), 2.50 (q, 2 H, J = 7.4 Hz), 1.29 (t, 3 H, J = 7.4 Hz). MS (70 eV): m/z = 251 (M+), 195.
12 Compound 3b was synthesized by the same procedure as described above, except the amount of catalyst and composition were changed.
