JOURNAL OF CHEMICAL RESEARCH 2017 507
.
+
–1
Experimental
found: 153 [M ]; IR (KBr, cm ): ν 3012, 2924, 1634, 1574, 1522, 1455,
384, 1343, 1289, 1260, 1097, 1024, 887, 819, 804, 735.
,3,5-Trimethyl-2-nitrobenzene (2f): Flash column chromatography
on a silica gel (ethyl acetate: petroleum ether, 1:20) gave 2f: Yellowish
1
All manipulations were carried out under air atmosphere and all
commercial chemicals were used without further purification. Column
chromatography was generally performed on silica gel (300–400
mesh) and reactions were monitored by thin layer chromatography
1
6
1
solid; yield 13.9 mg (42%); m.p. 39–41 °C (lit. 39–41 °C); H NMR
300 MHz, CDCl ): δ 2.28 (s, 6H), 2.31 (s, 3H), 6.92 (d, J = 0.5 Hz,
(
2
(
TLC) using UV light, to visualise the course of the reactions.
3
13
H); C NMR (75 MHz, CDCl ): δ 17.5, 21.0, 129.4, 129.6, 140.3,
3
.+
NMR spectra were recorded on either a 300 or 400 MHz Bruker
spectrometer. GC–MS spectra were recorded on a Shimadzu GCMS
QP-2010 spectrometer with an EI source. IR spectra were recorded on
a FTIR Bruker Vector 55 spectrometer using KBr discs. Melting points
were taken on an Electrothermal melting point apparatus and are used
without correction.
1
49.8; EI-MS calcd for C H NO : 165; found: 165 [M ]; IR (KBr,
9 11 2
–1
cm ): ν 3030, 2924, 2855, 1605, 1519, 1480, 1457, 1365, 859, 835, 701,
02.
Nitrobenzene (2g): Flash column chromatography on a silica gel
ethyl acetate/ petroleum ether, 1:20) gave 2g: Yellowish liquid;
yield 16.7 mg (68%); H NMR (300 MHz, CDCl ): δ 7.58–7.53 (m,
H), 7.74–7.68 (m, 1H), 8.23 (d, J = 8.2 Hz, 2H); C NMR (75 MHz,
6
6
(
1
3
3
1
2
CAUTION: In view of the explosive nature of hydroperoxide
reagents which were heated, all reactions were carried out on the
small scale indicated in fume hoods with anti-blast shields.
CDCl ): δ 123.8, 129.3, 134.7, 148.1; EI-MS calcd for C H NO : 123;
3
6
5
2
.
+
–1
found: 123 [M ]; IR (KBr, cm ): ν 3010, 2924, 2858, 2360, 2341, 1621,
606, 1588, 1521, 1478, 1349, 1316, 1261, 1107, 1069, 1021, 920, 851,
1
Synthesis of 2; general procedure
Under air, 1 (0.2 mmol), NH I (0.8 mmol), 70% TBHP in water
794, 700, 680.
4
1-Bromo-4-nitrobenzene (2h): Flash column chromatography on
a silica gel (ethyl acetate/petroleum ether, 1:25) gave 2h: Yellowish
solid; yield 29.6 mg (73%); m.p. 124 °C (lit. 125–127 °C); H NMR
(
2.4 mmol) and DMSO (0.5 mL) were added to a 10 mL Schlenk tube
sealed with a Teflon lined cap. The reaction mixture was stirred at
0 °C for 4 h in an oil bath. Upon completion, the reaction mixture was
6
1
9
13
(
300 MHz, CDCl ): δ 7.67–7.72 (m, 2H), 8.09–8.14 (m, 2H); C NMR
3
left to cool to room temperature and slowly quenched with anhydrous
sodium sulfite. The reaction mixture was then diluted with ethyl
acetate (5 mL) and then washed with water (5 × 5 mL). The aqueous
layer was extracted with EtOAc (3 × 5 mL). The combined organic
(
75 MHz, CDCl ): δ 125.0, 130.0, 132.7, 147.0; EI-MS calcd for
3
79
81
.+
C H BrNO : 201, for C H BrNO : 203; found: 201, 203 [M ]; IR
6
4
2
6
4
2
–1
(
1
KBr, cm ): ν 3104, 3011, 2924, 2851, 1604, 1599, 1577, 1520, 1344,
261, 1107, 1093, 1066, 1023, 848, 741, 704, 675.
1-Bromo-3-nitrobenzene (2i): Flash column chromatography on
layers were dried over Na SO . The filtrate was concentrated and the
2
4
crude product was purified by column chromatography on silica gel
with petroleum ether (60–90 °C)/ethyl acetate eluent. Characterisation
data are consistent with literature data.
a silica gel (ethyl acetate/petroleum ether, 1:25) gave 2i: Yellowish
low melting point solid; yield 14.2 mg (35%); m.p. 50–51 °C (lit.
21
1
5
1–52 °C); H NMR (300 MHz, CDCl ): δ 7.45 (t, J = 8.1 Hz, 1H),
3
1-Methyl-4-nitrobenzene (2a): Flash column chromatography on a
7
.82–7.87 (m, 1H), 8.16–8.20 (m, 1H), 8.39 (t, J = 2.0 Hz, 1H);
C NMR (75 MHz, CDCl ): δ 122.2, 122.9, 126.8, 130.6, 137.7, 148.8;
EI-MS calcd for C H BrNO : 201, for C H BrNO : 203; found: 201,
203 [M ]; IR (KBr, cm ): ν 3095, 3011, 2925, 2854, 1634, 1570, 1530,
1457, 1348, 1113, 1060, 980, 888, 869, 808, 731.
silica gel [ethyl acetate/petroleum ether (1:20)] gave 2a: Light yellow
13
3
6
1
solid; yield 23.3 mg (85%); m.p 48–50 °C (lit. 49–51 °C); H NMR
300 MHz, CDCl ): δ 2.47 (s, 3H), 7.32 (d, J = 8.7 Hz, 2H), 8.12 (d,
79
81
6
4
2
6
4
2
(
.+
–1
3
13
J = 8.4 Hz, 2H); C NMR (75 MHz, CDCl ): δ 20.6, 122.5, 128.8,
1
3
.
+
45.0; EI-MS calcd for C H NO : 137; found: 137 [M ]; IR (KBr,
7 7 2
1-Bromo-2-nitrobenzene (2j): Flash column chromatography on
a silica gel (ethyl acetate/petroleum ether, 1:25) gave 2j: Yellowish
–
1
cm ): ν 3012, 2963, 2923, 1599, 1519, 1495, 1450, 1345, 1261, 1097,
022, 802.
-Methyl-3-nitrobenzene (2b): Flash column chromatography on
a silica gel (ethyl acetate/petroleum ether, 1:20) gave 2b: Yellowish
1
21
1
solid; yield 15.4 mg (38%); m.p. 39–40 °C (lit. 38–40 °C); H NMR
19
1
(
300 MHz, CDCl ): δ 7.41–7.50 (m, 2H), 7.74–7.77 (m, 1H), 7.83–7.87
3
13
(
m, 1H); C NMR (75 MHz, CDCl ): δ 114.5, 125.7, 128.3, 133.2,
3
1
liquid; yield 10.3 mg (38%); H NMR (300 MHz, CDCl ): δ 2.47
79
81
3
135.1, 150.2; EI-MS calcd for C H BrNO : 201, for C H BrNO : 203;
6 4 2 6 4 2
(
s, 3H), 7.39–7.45 (m, 1H), 7.49–7.52 (m, 1H), 8.01–8.04 (m, 2H);
.+
–1
found: 201, 203 [M ]; IR (KBr, cm ): ν 3011, 2922, 2851, 1653, 1635,
1570, 1560, 1527, 1452, 1353, 1324, 1286, 1254, 1075, 1037, 869, 852,
831, 739.
1
3
C NMR (75 MHz, CDCl ): δ 21.3, 120.7, 123.9, 129.1, 135.4, 139.8,
48.2; EI-MS calcd for C H NO : 137; found: 137 [M ]; IR (KBr,
3
.
+
1
7 7 2
–1
cm ): ν 3010, 2923, 1634, 1601, 1574, 1522, 1384, 1343, 1289, 1097,
024, 820, 802, 754.
-Methyl-2-nitrobenzene (2c): Flash column chromatography on
a silica gel (ethyl acetate/petroleum ether, 1:20) gave 2c: Yellowish
1-Chloro-4-nitrobenzene (2k): Flash column chromatography on
1
a silica gel (ethyl acetate/petroleum ether, 1:25) gave 2k: Yellowish
2
0
1
6
1
solid; yield 22.7 mg (72%); m.p. 79–81 °C (lit. 81–83 °C); H NMR
13
(
300 MHz, CDCl ): δ 7.50–7.55 (m, 2H), 8.18–8.21 (m, 2H); C NMR
3
1
liquid; yield 11.4 mg (42%); H NMR (300 MHz, CDCl ): δ 2.61 (s,
3
(75 MHz, CDCl ): δ 125.0, 129.6, 141.4, 146.5; EI-MS calcd for
3
35 37 .+
3
H), 7.32–7.37 (m, 2H), 7.48–7.53 (m, 1H), 7.97 (d, J = 8.0 Hz, 1H);
C NMR (75 MHz, CDCl ): δ 20.5, 124.7, 126.9, 132.8, 133.0, 133.6,
49.6; EI-MS calcd for C H NO : 137; found: 137 [M ]; IR (KBr,
C H ClNO : 157, for C H ClNO : 159; found: 157, 159 [M ]; IR
6
4
2
6
4
2
13
–1
3
(KBr, cm ): ν 3104, 3012, 2924, 2851, 1604, 1577, 1520, 1476, 1420,
1355, 1344, 1313, 1107, 1093, 1012, 848, 741, 675.
.+
1
7 7 2
–1
cm ): ν 3030, 2923, 2852, 1596, 1558, 1515, 1465, 1442, 1381, 1336,
297, 1269, 1195, 1088, 1037, 955, 865, 828, 817, 745.
-Methoxy-4-nitrobenzene (2d): Flash column chromatography
on a silica gel (ethyl acetate/petroleum ether, 1:15) gave 2d: Beige
1-Chloro-3-nitrobenzene (2l): Flash column chromatography on a
1
silica gel (ethyl acetate/petroleum ether, 1:25) gave 2l; Yellowish solid;
1
21
1
yield 12.0 mg (38%); m.p. 43–44 °C (lit. 46–47 °C); H NMR (300
MHz, CDCl ): δ 7.52 (t, J = 8.2 Hz, 1H), 7.69 (dd, J = 8.0, 0.9 Hz, 1H),
3
6
1
solid; yield 19.0 mg (62%); m.p. 51–52 °C (lit. 50–52 °C); H NMR
300 MHz, CDCl ): δ 3.92 (s, 3H), 6.97 (d, J = 9.3 Hz, 2H), 8.22 (d,
13
8
.14 (dd, J = 8.2, 1.2 Hz, 1H), 8.24 (t, J = 2.0 Hz, 1H); C NMR (75
(
3
MHz, CDCl ): δ 121.7, 123.9, 130.4, 134.7, 135.4, 148.8; EI-MS calcd
3
35 37
13
J = 9.3 Hz, 2H); C NMR (75 MHz, CDCl ): δ 56.0, 114.0, 125.9, 141.5,
1
3
for C H ClNO : 157, for C H ClNO : 159; found: 157, 159 [M. ];
6 4 2 6 4 2 +
.
+
64.6; EI-MS calcd for C H NO : 153; found: 153 [M ]; IR (KBr,
–1
7
7
3
IR (KBr, cm ): ν 3011, 2922, 2851, 1631, 1570, 1560, 1528, 1452, 1352,
324, 1286, 1254, 1037, 869, 852, 832, 739, 669.
,4-Dinitrobenzene (2m): Flash column chromatography on a
silica gel (ethyl acetate/petroleum ether, 1:20) gave 2m: White solid;
–1
cm ): ν 3021, 2963, 2923, 2850, 1608, 1599, 1519, 1499, 1346, 1261,
097, 1022, 862, 846, 802, 751.
-Methoxy-3-nitrobenzene (2e): Flash column chromatography on
a silica gel (ethyl acetate/petroleum ether, 1:15) gave 2e: Yellowish
1
1
1
1
6
1
yield 19.8 mg (59%); m.p. 169–171 °C (lit. 165–166 °C); H NMR
1
oil; yield 10.8 mg (35%); H NMR (400 MHz, CDCl ): δ 3.82 (s, 3H),
7
J = 2.0 Hz, 1H), 7.73–7.75 (m, 1H); C NMR (75 MHz, CDCl ): δ 55.3,
1
13
3
(300 MHz, CDCl ): δ 8.44 (s, 4H); C NMR (75 MHz, CDCl ): δ
124.9, 151.0; EI-MS calcd for C H N O : 168; found: 168 [M ]; IR
6 4 2 4
(KBr, cm ): ν 3123, 3109, 3020, 2960, 2924, 2852, 1945, 1730, 1560,
1477, 1409, 1388, 1345, 1320, 1104, 1010, 872, 839, 819, 710, 517.
3
3
.15 (dd, J = 8.3 Hz, J = 2.4 Hz, 1H), 7.35 (t, J = 8.2 Hz, 1H), 7.65 (t,
.+
1
2
13
–1
3
07.6, 115.3, 120.8, 129.4, 148.8, 159.7; EI-MS calcd for C H NO : 153;
7 7 3