9
10.67 (1H, s, OH), 7.94 (1H, d, J 2 Hz, H at C-6), 7.52 (1H, dd, J
9, 2 Hz, H at C4), 6.87 (1H, d, J 9 Hz, H at C-3), 3.95 (3H, s,
OCH3); 13C NMR (75 MHz, CDCl3): δ 171.0, 161.0, 138.6,
132.4, 119.9, 114.1, 110.9, 52.7; GC-MS (EI), m/z (rel int.): 233
(3, (M+3)+), 232 (36, (M+2)+), 231 (4, (M+1)+), 230 (37, M+),
200 (98, ((M+2)-HOCH3)+), 199 (20), 198 (100, (M-HOCH3)+),
173 (8), 172 (37), 171 (8), 170 (37), 143 (9), 136 (2), 119 (5), 91
(8), 64 (11), 63 (50), 62 (16), 53 (13), 38 (5); IR (neat): 3183,
1737, 1079 cm-1.
5.2.14. 2-Bromo-9H-fluoren-9-one (14a).20 Yellow solid;
1
ACCEPTED MANUSCRIPT
yield: 38% (0.3912 g). Mp 129-131 °C, lit.21 128-130 °C; H
NMR (300 MHz, CDCl3): δ 7.76 (1H, d, J 2 Hz, H at C-1), 7.61
(1H, dd, J 8, 2 Hz, H at C-3), 7.51 (2H, d, J 4 Hz, Hs at C-5 and
C-8), 7.40 (1H, d, J 8 Hz, H at C-6), 7.39 (1H, d, J 8 Hz, H at C-
4), 7.37-7.30 (1H, m, H at C-7); 13C NMR (75 MHz, CDCl3): δ
192.3, 143.6, 143.0, 137.1, 135.8, 135.0, 133.7, 129.4, 127.5,
124.6, 122.7, 121.7, 120.4; GC-MS (EI), m/z (rel int.): 260 (98,
(M+2)+), 258 (100, M+), 232 (3, ((M+2)-CO)+), 230 (4, (M-
CO)+), 179 (2, (M-Br)+), 152 (7, ((M+1)-Br-CO)+), 151 (49, (M-
Br-CO)+), 116 (4), 115 (4), 98 (4), 75 (13); IR (neat): 1716, 1076
cm-1
5.2.9.
2-Acetyl-4-Bromophenol (9a).6c White solid; yield: 87%
1
(0.0937 g). H NMR (300 MHz, CDCl3): δ 12.16 (1H, s, OH),
7.84 (1H, d, J 2 Hz, H at C-3), 7.55 (1H, dd, J 9, 2 Hz, H at C5),
6.90 (1H, d, J 9 Hz, H at C-6), 2.64 (3H, s, CH3); 13C NMR (75
MHz, CDCl3): δ 203.5, 161.3, 139.1, 132.9, 125.0, 120.5, 110.4,
26.7; GC-MS (EI), m/z (rel int.): 217 (5, (M+3)+), 216 (51,
(M+2)+), 215 (5, (M+1)+), 214 (52, M+), 202 (8), 201 (97,
((M+2)-CH3)+), 199 (100, (M-CH3)+), 173 (17), 172 (3), 171
(17), 145 (12), 143 (13), 119 (3) 117 (4), 92 (7), 64 (9), 63 (28),
62 (11), 53 (11), 43 (24, CH3CO+); IR (neat): 2923, 1643, 1084
cm-1.
5.3 Iodination of acetanilide
Thiourea (5.2 mol%, 2 mg, 0.026 mmol) was added to an
acetonitrile solution (10 mL) containing N-iodosuccinimide (1.0
equiv, 113 mg, 0.5 mmol). Acetanilide (67.4 mg, 0.5 mmol) was
added immediately to the resulting stirred solution and allowed to
stir at room temperature for 2 hours. The reaction was quenched
by the addition of 10% aqueous solution of Na2S2O3 (10 mL) and
extracted with ethyl acetate (70 mL). The organic solution was
then washed with additional 10% Na2S2O3 (2 x 10 mL), followed
by deionized water (3 x 15 mL) and brine (2x 10 mL). The
organic solution was then dried over anhydrous Na2SO4 and the
solvent was evaporated in vacuo to give an off-white crude solid,
which was purified by centrifugal thin-layer chromatography
using a 2 mm thick silica gel 60GF254 coated plate (5%
EtOAc/CH2Cl2) to give N-(4-iodophenyl)acetamide (0.0972 g,
74%) as an off-white solid; Mp (H2O) 179-181 °C, lit.18 180-182
°C; 1H NMR (300 MHz, CD3OD): δ 7.58 (2H, d, J 9 Hz, Hs at C-
3 and C-5), 7.33 (2H, d, J 9 Hz, Hs at C2 and C6), 2.08 (3H, s,
COCH3); 13C NMR (75 MHz, CD3OD): δ 171.8, 140.0, 139.0,
123.1, 87.8, 24.0; GC-MS (EI), m/z (rel int.): 262 (6, (M+2)+),
261 (58, M+), 220 (8, ((M+2)-COCH3+H)+) 219 (100, (M-
COCH3+H)+), 191 (3), 127 (2, I), 92 (21, (M-COCH3+H-I)+), 91
(5), 65 (11), 64 (6), 63 (8), 43 (13, (COCH3)+); IR (neat): 3287,
3252, 1664, 1061 cm-1.
5.2.10. 1-Bromonaphthalene (10a).16 Colourless liquid; yield:
1
78% (0.1623 g). H NMR (300 MHz, CDCl3): δ 8.24 (1H, d, J 8
Hz, H at C-2), 7.84-7.78 (3H, m, Hs at C-4, C-5 and C-8), 7.60-
7.53 (2H, m, Hs at C-6 and C-7), 7.32 (1H, t, J 8 Hz, H at C-3);
13C NMR (75 MHz, CDCl3): δ 134.7, 129.9, 128.3, 127.9, 127.3,
127.1, 126.7, 126.2, 122.9, 118.8; GC-MS (EI), m/z (rel int.): 209
(10, (M+3)+), 208 (97, (M+2)+), 207 (12, (M+1)+), 206 (100, M+),
128 (8, ((M+1)-Br)+), 127 (75, (M-Br)+), 104 (7), 103 (8), 87 (3),
86 (2), 77 (8), 76 (4), 75 (8), 74 (8), 63 (13); IR (neat): 3053,
1591, 1561, 1056 cm-1.
5.2.11. 2-Bromofluorene (11a).17 White solid; yield: 71% (0.1744
g). Mp 103-104 °C, lit.18 102-103 °C; 1H NMR (300 MHz,
CDCl3): δ 7.75 (1H, d, J 8 Hz, H at C-3), 7.68 (1H, d, J 1 Hz, H
at C-1), 7.64 (1H, d, J 8 Hz, H at C-4), 7.50 (1H, d, J 8 Hz, H at
C-5), 7.54 (1H, d, J 8 Hz, H at C-8), 7.41-7.30 (2H, m, Hs at C-6
and C-7), 3.89 (2H, s, Hs at C-9); 13C NMR (75 MHz, CDCl3): δ
145.2, 142.9, 140.7, 130.2, 129.9, 128.3, 127.2, 127.0, 125.1,
121.1 120.4, 120.0; GC-MS (EI), m/z (rel int.): 247 (3, (M+3)+),
246 (26, (M+2)+), 245 (5, (M+1)+), 244 (25, M+), 166 (14,
((M+1)-Br)+), 165 (100, (M-Br)+), 164 (13), 163 (23), 162 (4),
139 (3), 115 (2), 83 (13), 82 (7), 63 (2); IR (neat): 3031, 1601,
1567, 1061 cm-1.
5.4 UV-vis experiments
5.4.1 Preparation of UV-vis spectra of NBS with 1-5% thiourea
The solutions of thiourea, NBS, and NBS with 1-5% thiourea
were prepared in the same manner as those of NCS-thiourea
studies. The amounts of thiourea used for the 50 mL acetonitrile
stock solution was 0.0190 g (mmol). The aliquots of freshly-
made thiourea stock solution for 1%, 2%, 3% and 5% solutions
of thiourea with 0.5 mmol of NBS (0.0890 g) were 1, 2, 3 and
mL, respectively. These solutions were stirred for 10 minutes
before their UV-vis spectra were recorded. The order of spectra
recording was the same as in the NCS study with the 1% solution
first and 5% solution last. A UV-vis spectrum of 5% thiourea,
made in the same manner as stated above for NCS, was recorded
after the NBS and 5% thiourea solution recording. A UV-vis
spectrum of NBS (0.0890 g, 0.5 mmol) in 10 mL of acetonitrile
was recorded 10 minutes after it was made but before the
recording of the NBS and 1% thiourea solution.
5.2.12. 1-Bromo-2,5-dimethylbenzene (12a).18 Colourless liquid;
1
yield: 72% (0.2670 g). H NMR (300 MHz, CDCl3): δ 7.37 (1H,
s, H at C-3), 7.11 (1H, d, J 8 Hz, H at C-6), 7.01 (1H, d, J 8 Hz,
H at C-5), 2.36 (3H, s, CH3), 2.30 (3H, s, CH3); 13C NMR (75
MHz, CDCl3): δ 137.2, 134.6, 132.8, 130.5, 128.0, 124.7, 22.4,
20.6; GC-MS (EI), m/z (rel int.): 187 (6, (M+3)+), 186 (64,
(M+2)+), 185 (11, (M+1)+), 184 (64, M+), 171 (7, ((M+2)-CH3)+),
169 (7, ((M-CH3)+), 106 (9, ((M+1)-Br)+), 105 (100, (M-Br)+),
104 (11), 103 (25), 89 (4), 79 (19), 78 (15), 77 (25), 63 (9), 51
(17); IR (neat): 3019, 2922 cm-1.
5.2.13. 3-Bromo-4-methoxybenzaldehyde (13a).19 White solid;
1
yield: 77% (0.3318 g). Mp 45-46 °C, lit.20 43-44 °C; H NMR
5.4.2 Preparation of UV-vis spectra of NBS with 5% thiourea
and acetanilide
(300 MHz, CDCl3): δ 9.84 (1H, s, CHO), 8.07 (1H, d J 2 Hz, H
at C-2), 7.82 (1H, dd, J 8, 2 Hz, H at C-6), 7.01 (1H, d, J 8 Hz, H
at C-5), 3.99 (3H, s, OCH3); 13C NMR (75 MHz, CDCl3): δ
189.5, 160.6, 134.5, 131.2, 130.8, 112.7, 111.6, 56.6; GC-MS
(EI), m/z (rel int.): 216 (75, (M+2)+), 215 (100, ((M+2)-H)+), 214
(76, M+), 213 (96, (M-H)+), 188 (1), 187 (5), 186 (1), 185 (5),
157 (7), 155 (6), 145 (11), 143 (12), 119 (8), 92 (3), 78 97), 77
(9), 76 (8), 75 (9), 74 (8), 63 (22); IR (neat): 1683, 1048 cm-1.
A 10 mL solution of 5% thiourea (2.5 mM) was prepared in a
10 mL volumetric flask by dissolving thiourea (0.0190 g, mol) in
acetonitrile. Three 10 mL solutions of 0.5 mmol of NBS (0.0890
g) were made in separate 10 mL volumetric flasks with the first
one also containing 5% thiourea (1 mL of the 5% stock solution,
the second containing 5% thiourea (1 mL aliquot) and 0.0125 M
acetanilide (0.0169 g, mmol) and the third containing 5%