4
Tetrahedron
by flash column chromatography on silica gel afforded the desired
products 2.
121.7, 115.6, 114.2, 102.4, 36.5. HRMS (ESI-QTOF): m/z (M +
H)+ calcd for C10H11BrN3O: 268.0085; found: 268.0078.
3-(4-bromophenyl)-1,1-dimethylurea
(2a):
Eluent:
3-(4-bromo-2-nitrophenyl)-1,1-dimethylurea (2h): Eluent:
dichloromethane: petroleum ether (15:1). Yellow solid, 25 mg,
yield: 44%, mp: 103-105 oC. 1H NMR (300 MHz, CDCl3): δ
dichloromethane: ethyl acetate (120:1). White solid, 28 mg,
yield: 64%. mp: 170-172 oC. 1H NMR (300 MHz, CDCl3): δ
7.38 (d, J = 8.7 Hz, 2H), 7.28 (d, J = 8.7 Hz, 2H), 6.38 (s, 1H),
3.03 (s, 6H). 13C NMR (75 MHz, CDCl3): δ 155.5, 138.4, 131.7,
121.5, 115.3, 36.4. HRMS (ESI-QTOF): m/z (M + H)+ calcd for
C9H12BrN2O: 243.0133; found: 243.0130.
10.17 (s, 1H), 8.68 (d, J = 9.2 Hz, 1H), 8.37 (d, J = 1.5
Hz, 1H), 7.70 (dd, J = 2.2, 9.2 Hz, 1H), 3.13 (s, 6H). 13C NMR
(75 MHz, CDCl3): δ 154.3, 138.8, 136.6, 135.7, 128.0, 122.8,
113.1, 36.5. HRMS (ESI-QTOF): m/z (M + H)+ calcd for
C9H10BrN3O3: 287.9984; found:287.9977.
3-(2-bromophenyl)-1,1-dimethylurea (2a’): White solid, 5
o
1
mg, yield: 11%. mp: 89-90 C. H NMR (300 MHz, CDCl3): δ
8.23 (d, J = 8.4 Hz, 1H), 7.48 (d, J = 8.1 Hz, 1H), 7.29 (d, J =
7.5 Hz, 1H), 7.01 (s, 1H), 6.85-6.91 (m, 1H), 3.03 (s, 6H). 13C
NMR (75 MHz, CDCl3): δ 155.0, 137.1, 131.9, 128.3, 123.4,
120.9, 113.0, 36.4. HRMS (ESI-QTOF): m/z (M + H)+ calcd for
C9H12BrN2O: 243.0133; found: 243.0140.
3-(4-bromo-3-methoxyphenyl)-1,1-dimethylurea
(2i):
Eluent: dichloromethane: petroleum ether (10:1). White solid,
28 mg, yield: 52%. mp: 140-142 oC. 1H NMR (300 MHz,
CDCl3): δ 7.43 (s, 1H), 7.36 (d, J = 8.5 Hz, 1H), 6.64 (dd, J =
1.8, 8.4 Hz, 1H), 6.51 (s, 1H), 3.87 (s, 1H), 3.03 (s, 6H). 13C
NMR (75 MHz, CDCl3): δ 156.0, 155.4, 140.0, 112.4, 112.3,
104.1, 56.2, 36.5. HRMS (ESI-QTOF): m/z (M + H)+ calcd for
C10H14BrN2O2: 273.0239; found: 273.0237.
3-(4-bromo-2-methoxyphenyl)-1,1-dimethylurea
(2b):
Eluent: dichloromethane: petroleum ether (4:1). Purple oil, 36
mg, yield: 67%. 1H NMR (300 MHz, CDCl3): δ 8.10 (d, J = 8.7
Hz, 1H), 7.07 (d, J = 8.7 Hz, 1H), 7.0 (s, 1H), 6.97 (s, 1H), 3.87
(s, 3H), 3.05 (s, 6H). 13C NMR (75 MHz, CDCl3): δ 155.2,
148.2, 128.3, 123.8, 119.8, 113.8, 113.1, 56.0, 36.3. HRMS
(ESI-QTOF): m/z (M + H)+ calcd for C10H14BrN2O2: 273.0239;
found: 273.0233.
3-(4-bromo-3-methylphenyl)-1,1-dimethylurea
(2j):
Eluent: dichloromethane: petroleum ether (2:1). White solid, 36
mg, yield: 70%. mp: 149-151 oC. 1H NMR (300 MHz, CDCl3): δ
7.27 (d, J = 8.6 Hz, 1H), 7.22 (s, 1H), 6.95 (d, J = 8.4 Hz, 1H),
6.13 (s, 1H), 2.90 (s, 6H), 2.23 (s, 3H). 13C NMR (75 MHz,
CDCl3): δ 155.5, 138.4, 138.2, 132.3, 122.1, 118.8, 117.9, 36.5,
23.0. HRMS (ESI-QTOF): m/z (M + H)+ calcd for C10H14BrN2O:
257.0290; found: 257.0286.
3-(4-bromo-2-methylphenyl)-1,1-dimethylurea
(2c):
Eluent: dichloromethane: petroleum ether (15:1). White solid,
42 mg, yield: 82%. mp: 90-92 oC. 1H NMR (300 MHz, CDCl3):
δ 7.60 (d, J = 9.2 Hz, 1H), 7.28 (s, 2H), 6.14 (s, 1H), 3.02 (s,
6H), 2.02 (s, 6H). 13C NMR (75 MHz, CDCl3): δ 155.6, 136.4,
132.8, 130.5, 129.5, 124.0, 116.3, 36.4, 17.6. HRMS (ESI-
QTOF): m/z (M + H)+ calcd for C10H14BrN2O: 257.0290; found:
257.0283.
3-(4-bromo-3-chlorophenyl)-1,1-dimethylurea
(2k):
Eluent: dichloromethane: petroleum ether (15:1). White solid,
45 mg, yield: 82%. mp: 165-167 oC. 1H NMR (300 MHz,
DMSO-d6): δ 8.56 (s, 1H), 7.86 (s, 1H), 7.58 (d, J = 8.8 Hz, 1H),
7.42 (d, J = 8.8 Hz, 1H), 2.92 (s, 6H). 13C NMR (75 MHz,
DMSO-d6): δ 155.6, 142.1, 133.7, 133.0, 120.8, 120.0, 112.7,
3-(4-bromo-2-chlorophenyl)-1,1-dimethylurea
(2d):
36.6. HRMS (ESI-QTOF): m/z (M
C9H11BrClN2O: 276.9743; found: 276.9735.
+
H)+ calcd for
Eluent: dichloromethane: petroleum ether (100:1). White solid,
45 mg, yield: 82%. mp: 74-76 oC. 1H NMR (300 MHz, CDCl3):
δ 8.17 (d, J = 8.9 Hz, 1H), 7.47 (d, J = 2.0 Hz, 1H), 7.35 (dd, J =
2.0, 8.8 Hz, 1H), 6.95 (s, 1H), 3.07 (s, 6H). 13C NMR (75 MHz,
CDCl3): δ 154.6, 135.3, 131.0, 130.7, 122.6, 121.7, 114.2, 36.4.
HRMS (ESI-QTOF): m/z (M + H)+ calcd for C9H11BrClN2O:
276.9743; found: 276.9738.
3-(3,4-dibromophenyl)-1,1-dimethylurea (2l): Eluent:
dichloromethane: petroleum ether (1:2). White solid, 41 mg,
yield: 64%. mp: 175-177 oC. 1H NMR (300 MHz, CDCl3): δ
7.74 (s, 1H), 7.45 (d, J = 8.3 Hz, 1H), 7.23 (t, J = 9.2, 7.3 Hz,
1H), 6.44 (s, 1H), 3.00 (s, 6H). 13C NMR (75 MHz, DMSO-d6):
δ 155.6, 142.0, 133.6, 124.0, 123.6, 120.4, 115.1, 36.6. HRMS
(ESI-QTOF): m/z (M + H)+ calcd for C9H11Br2N2O: 322.9218;
found: 322.9217.
3-(2,4-dibromophenyl)-1,1-dimethylurea (2e): Eluent:
dichloromethane: petroleum ether (8:1).White solid, 47 mg,
o
1
yield: 72%. mp: 80-81 C. H NMR (300 MHz, CDCl3): δ 8.16
(d, J = 8.9 Hz, 1H), 7.62 (d, J = 1.3 Hz, 1H), 7.37 (dd, J = 1.5,
8.9 Hz, 1H), 6.96 (s, 1H), 3.06 (s, 6H). 13C NMR (75 MHz,
CDCl3): δ 154.7, 136.4, 133.9, 131.3, 121.8, 114.7, 113.2, 36.4.
HRMS (ESI-QTOF): m/z (M + H)+ calcd for C9H11Br2N2O:
322.9218; found: 322.9212.
3-(4-bromo-2,3-dimethylphenyl)-1,1-dimethylurea (2m):
Eluent: dichloromethane: ethyl acetate (120:1). White solid, 47
mg, yield: 86%. mp: 182-184 oC. 1H NMR (300 MHz, CDCl3): δ
7.23 (d, J = 8.6 Hz, 1H), 7.08 (d, J = 8.6 Hz, 1H), 6.00 (s, 1H),
2.89 (s, 6H), 2.26 (s, 3H), 2.06 (s, 3H). 13C NMR (75 MHz,
CDCl3): δ 156.2, 136.4, 136.2, 131.5, 129.9, 123.4, 121.2, 36.5,
20.4, 15.3. HRMS (ESI-QTOF): m/z (M + H)+ calcd for
C11H16BrN2O: 271.0466; found: 271.0438.
methyl 5-bromo-2-(3,3-dimethylureido)benzoate (2f):
Eluent: dichloromethane: petroleum ether (15:1). White solid,
51 mg, yield: 85%. mp: 143-144 oC. 1H NMR (300 MHz,
CDCl3): δ 10.62 (s, 1H), 8.57 (d, J = 9.2 Hz, 1H), 8.13 (d, J =
2.2 Hz, 1H), 7.60 (dd, J = 2.2, 9.2 Hz, 1H), 3.94 (s, 1H), 3.11 (s,
6H). 13C NMR (75 MHz, CDCl3): δ 168.2, 155.2, 142.7, 137.2,
133.0, 121.1, 115.2, 112.6, 52.4, 36.3. HRMS (ESI-QTOF): m/z
(M + H)+ calcd for C11H14BrN2O3: 301.0188; found: 301.0185.
3-(4-bromo-2,5-dimethylphenyl)-1,1-dimethylurea (2n):
Eluent: dichloromethane: petroleum ether (15:1). White solid,
31 mg, yield: 58%. mp: 112-113 oC. 1H NMR (300 MHz,
CDCl3): δ 7.64 (s, 1H), 7.30 (s, 1H), 6.08 (s, 1H), 3.03 (s, 6H),
2.34 (s, 3H), 2.18 (s, 3H). 13C NMR (75 MHz, CDCl3): δ 155.7,
136.3, 135.9, 133.3, 127.6, 124.6, 118.9, 36.4, 22.6, 17.0.
HRMS (ESI-QTOF): m/z (M + H)+ calcd for C11H16BrN2O:
271.0466; found: 271.0441.
3-(4-bromo-2-cyanophenyl)-1,1-dimethylurea
(2g):
Eluent: dichloromethane. White solid, 37 mg, yield: 69%. mp:
118-120 oC. 1H NMR (300 MHz, CDCl3): δ 8.21 (d, J = 9.6 Hz,
1H), 7.61 (d, J = 7.6 Hz, 1H), 7.59 (s, 1H), 6.96 (s, 1H), 3.06 (s,
6H). 13C NMR (75 MHz, CDCl3): δ 154.0, 141.6, 137.2, 133.7,
3-(4-bromo-3-chloro-2-fluorophenyl)-1,1-dimethylurea
(2o): Eluent: dichloromethane: petroleum ether (15:1). White
o
1
solid, 38 mg, yield: 65%. mp: 126-128 C. H NMR (300 MHz,