6934
P. Bovonsombat et al. / Tetrahedron 66 (2010) 6928e6935
twice. The ether solution was then dried over anhydrous Na2SO4.
The product composition was determined by GCeMS. The major
product of each reaction was isolated by silica gel chromatogra-
phy (10e20% CH2Cl2/hexanes). The products reported herein,
except for compounds 6a and 6b, are known compounds and
were characterized by GCeMS, 1H and 13C NMR. The spectro-
scopic data of the known compounds are in agreement with
those reported in the literature.
(EI), m/z (rel int.): (100, Mþ), (98, (Mþ2)þ); IR (neat):
3513 cmꢂ1
.
4.2.9. 1-Bromo-2-naphthol (9a)17. White solid; yield: 91% (0.101 g).
1H NMR (300 MHz, CDCl3):
8.01 (1H, d, J 9 Hz, H at C-9), 7.75 (1H,
d
d, J 9 Hz, H at C-6), 7.71 (1H, d, J 9 Hz, H at C-4), 7.55 (1H, m, H at C-
8), 7.37 (1H, m, H at C-7), 7.25 (1H, d, J 9 Hz, H at C-3), 5.93 (1H, s,
OH); 13C NMR (75 MHz, CDCl3):
d 150.6, 132.3, 129.7, 129.3, 128.2,
127.8, 125.3, 124.1, 117.1, 106.1; GCeMS (EI), m/z (rel int.): 222 (100,
4.2.1. 4-Bromophenol (1a)11. Colourless liquid; yield: 87%
Mþ), 224 (97, (Mþ2)þ); IR (neat): 3507 cmꢂ1
.
(0.075 g). 1H NMR (300 MHz, CDCl3):
d
7.32 (2H, d, J 8 Hz, Hs at C-3
and C-5), 6.72 (2H d, J 8 Hz, Hs at C-2 and C-6), 5.54 (1H, br s, OH);
4.2.10. 4-Chlorophenol (1b)18. Colourless liquid; yield: 73%
(0.031 g). 1H NMR (300 MHz, CDCl3):
7.15 (2H, d, J 9 Hz, Hs at C-3
and C-5), 6.74 (2H, d, J 9 Hz, Hs at C-2 and C-6); 13C NMR (75 MHz,
13C NMR (75 MHz, CDCl3):
d
154.8, 132.5, 117.2, 112.7; GCeMS (EI),
d
m/z (rel int.): 172 (100, Mþ), 174 (98, (Mþ2)þ); IR (neat):
3339 cmꢂ1
.
CDCl3): d 153.9, 129.6, 125.7, 116.8; GCeMS (EI), m/z (rel int.): 128
(100, Mþ), 130 (34, (Mþ2)þ); IR (neat): 3368 cmꢂ1
.
4.2.2. 4-Bromo-2-methoxyphenol (2a)12. Colourless liquid; yield:
82% (0.083 g). 1H NMR (300 MHz, CDCl3):
7.01 (1H, dd, J 8, 2 Hz, H
at C-5), 6.98 (1H, d, J 2 Hz, H at C-3), 6.82 (1H, d, J 8 Hz, H at C-6),
3.88 (s, 3H); 13C NMR (75 MHz, CDCl3):
147.3, 144.9, 124.2, 115.8,
d
4.2.11. 4-Chloro-2-methoxyphenol (2b)18a. Colourless liquid; yield:
44% (0.035 g). 1H NMR (300 MHz, CDCl3):
6.84 (3H, s, Hs at C-3,
C-5 and C-6), 5.55 (1H, s, OH), 3.87 (3H, s, CH3); 13C NMR (75 MHz,
d
d
114.2, 111.6, 56.2; GCeMS (EI), m/z (rel int.): 202 (100, Mþ), 204 (98,
CDCl3): d 147.0, 144.3, 124.6, 121.1, 115.2, 111.4, 56.1; GCeMS (EI),
(Mþ2)þ); IR (neat): 3538 cmꢂ1
.
m/z (rel int.): 158 (97, Mþ), 160 (32, (Mþ2)þ); IR (neat):
3539 cmꢂ1
.
4.2.3. 4-Bromo-2-chlorophenol (3a)6m. White solid; yield: 81%
(0.084 g). 1H NMR (300 MHz, CDCl3):
7.46 (1H, d, J 2 Hz, H at C-3),
7.28 (1H, dd, J 9, 2 Hz, H at C-5), 6.90 (1H, d, J 9 Hz, H at C-6); 13C
d
4.2.12. 2-Bromo-4-chlorophenol (10b)6m. Colourless liquid; yield:
42% (0.043 g). 1H NMR (300 MHz, CDCl3):
7.46 (1H, d, J 2 Hz, H at
C-3), 7.19 (1H, dd, J 9, 2 Hz, H at C-5), 6.95 (1H, d, J 9 Hz, H at C-6);
d
NMR (75 MHz, CDCl3):
d 150.7, 131.4, 125.0, 120.8, 117.7, 112.3;
GCeMS (EI), m/z (rel int.): 206 (77, Mþ), 208 (100, (Mþ2)þ), 210 (24,
13C NMR (75 MHz, CDCl3):
d 151.2, 131.4, 129.2, 121.8, 116.9, 110.4;
(Mþ4)þ); IR (neat): 3531 cmꢂ1
.
GCeMS (EI), m/z (rel int.): 206 (78, Mþ), 208 (100, (Mþ2)þ), 210 (24,
(Mþ4)þ); IR (neat): 3504 cmꢂ1
.
4.2.4. 2-Acetyl-4-bromophenol (4a)13. White solid; yield: 50%
(0.054 g). 1H NMR (300 MHz, CDCl3):
7.84 (1H, d, J 2 Hz, H at C-3),
7.55 (1H, dd, J 9, 2 Hz, H at C-5), 6.90 (1H, d, J 9 Hz, H at C-6), 2.63
(3H, s, COCH3); 13C NMR (75 MHz, CDCl3):
203.6, 161.3, 139.1,
d
4.2.13. 2-Acetyl-4-chloro-phenol (4b). White solid; yield: 49%
(0.042 g). 1H NMR (300 MHz, CDCl3):
12.14 (1H, s, OH), 7.69 (1H,
d
d
d, J 2 Hz, H at C-3), 7.41 (1H, dd, J 9, 2 Hz, H at C-5), 6.94 (1H, d, J
132.9, 125.0, 120.5, 110.4, 26.7; GCeMS (EI), m/z (rel int.): 214 (55,
9 Hz, H at C-6), 2.62 (3H, s, COCH3); 13C NMR (75 MHz, CDCl3):
Mþ), 216 (54, (Mþ2)þ); IR (neat): 3616, 1647 cmꢂ1
.
d 203.6, 160.9, 136.3, 129.9, 123.6, 120.3, 120.1, 26.7; GCeMS (EI),
m/z (rel int.): 170 (48, Mþ), 172 (15, (Mþ2)þ); IR (neat): 3467,
4.2.5. Methyl 5-bromo-2-hydroxybenzoate (5a)14. Colourless liquid;
yield: 72% (0.083 g). 1H NMR (300 MHz, CDCl3):
10.69 (1H, s, OH),
1648 cmꢂ1
.
d
7.94 (1H, d, J 2 Hz, H at C-6), 7.52 (1H, dd, J 9, 2 Hz, H at C-4), 6.88
4.2.14. Methyl 5-chloro-2-hydroxybenzoate (5b)19. White solid;
yield: 57% (0.053 g). 1H NMR (300 MHz, CDCl3):
10.67 (1H, s, OH),
(1H, d, J 9 Hz, H at C-3), 3.96 (3H, s, CO2CH3); 13C NMR (75 MHz,
d
CDCl3):
d
169.5, 160.6, 140.9, 138.4, 119.5, 113.8, 110.8, 52.6; GCeMS
7.79 (1H, d, J 2 Hz, H at C-6), 7.39 (1H, dd, J 9, 2 Hz, H at C-4), 6.92
(EI), m/z (rel int.): 230 (38, Mþ), 232 (37, (Mþ2)þ); IR (neat): 3437,
(1H, dd, J 9, 0.9 Hz, H at C-3), 3.95 (3H, s, CO2CH3); 13C NMR
1681 cmꢂ1
.
(75 MHz, CDCl3): d 169.6, 160.2, 135.7, 129.2, 123.9, 119.2, 113.3,
52.6; GCeMS (EI), m/z (rel int.): 186 (41, Mþ), 188 (14, (Mþ2)þ); IR
4.2.6. 3-Acetyl-4-bromophenol (6a). White solid; yield: 45%
(0.048 g). Mp (ether/pet. ether) 76e77 ꢀC; 1H NMR (300 MHz,
(neat): 3436, 1678 cmꢂ1
.
CDCl3):
d
7.43 (1H, d, J 9 Hz, H at C-5), 6.96 (1H, d, J 3 Hz, H at C-2),
4.2.15. 3-Acetyl-4-chlorophenol (6b). White solid; yield: 33%
(0.028 g). Mp (ether/pet. ether) 79e81 ꢀC. 1H NMR (300 MHz,
6.82 (1H, dd, J 9, 3 Hz, H at C-6), 2.64 (3H, s, COCH3); 13C NMR
(75 MHz, CDCl3):
d
202.7, 155.4, 142.0, 134.9, 119.6, 116.0, 108.9,
CDCl3):
d 7.27 (1H, d, J 9 Hz, H at C-6), 7.07 (1H, d, J 3 Hz, H at C-2),
30.4; GCeMS (EI), m/z (rel int.): 214 (42, Mþ), 216 (44, (Mþ2)þ); IR
(neat): 3499,1694 cmꢂ1; Anal. Calcd for C8H7BrO2: C, 44.68; H, 3.28.
Found: C, 44.86; H, 2.99.
6.91 (1H, dd, J 9, 3 Hz, H at C-5), 2.66 (3H, s, COCH3); 13C NMR
(75 MHz, CDCl3): d 201.3, 154.8, 139.5, 131.8, 122.6, 119.7, 116.1, 30.8;
GCeMS (EI), m/z (rel int.): 170 (44, Mþ), 172 (14, (Mþ2)þ); IR (neat):
3401, 1688 cmꢂ1; Anal. Calcd for C8H7ClO2: C, 56.32; H, 4.14. Found:
C, 56.80; H, 4.14.
4.2.7. 2-Bromo-5-hydroxybenzaldehyde (7a)15. White solid; yield:
51% (0.051 g). 1H NMR (300 MHz, CDCl3):
d
10.29 (1H, s, CHO), 7.51
(1H, d, J 9 Hz, H at C-3), 7.45 (1H, d, J 3 Hz, H at C-6), 7.03 (1H, dd, J 9,
3 Hz, H at C-4); 13C NMR (75 MHz, CDCl3):
192.5, 155.8, 134.9,
4.2.16. 2-Chloro-5-hydroxybenzaldehyde (7b). White solid; yield:
d
42% (0.033 g). 1H NMR (300 MHz, CDCl3):
d 10.41 (1H, s, CHO), 7.41
123.6, 117.6, 115.7, 114.7; GCeMS (EI), m/z (rel int.): 200 (89, Mþ),
(1H, d, J 3 Hz, H at C-6), 7.34 (1H, d, J 9 Hz, H at C-3), 7.07 (1H, dd, J 9,
202 (88, (Mþ2)þ); IR (neat): 3502, 1695 cmꢂ1
.
3 Hz, H at C-4), 5.97 (1H, br s, OH); 13C NMR (75 MHz, CDCl3):
d
190.0, 154.9, 133.0, 131.8, 125.0, 123.0, 115.0; GCeMS (EI), m/z (rel
4.2.8. 2-Bromo-4-methylphenol (8a)16. Colourless liquid; yield:
88% (0.082 g). 1H NMR (300 MHz, CDCl3):
7.26 (1H, d, J 1 Hz, H
int.): 156 (84, Mþ), 158 (28, (Mþ2)þ); IR (neat): 3435, 1664 cmꢂ1
.
d
at C-3), 7.00 (1H, dd, J 8, 1 Hz, H at C-5), 6.90 (1H, d, J 8 Hz, H at
4.2.17. 2-Chloro-4-methylphenol (8b). Colourless liquid; yield: 40%
(0.028 g). 1H NMR (300 MHz, CDCl3):
7.03 (1H, s, H at C-3), 6.86
(2H, s, Hs at C-5 and C-6), 2.17 (3H, s, CH3); 13C NMR (75 MHz,
C-6), 5.39 (1H, br s, OH), 2.26 (3H, s, CH3); 13C NMR (75 MHz,
d
CDCl3):
d 150.0, 132.1, 131.4, 129.8, 115.8, 109.8, 20.2; GCeMS