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The Journal of Organic Chemistry
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to provide air supply. The reaction vial was placed in a custom-built cooling system at 25 °C and irradiated under stirring with a 455 nm
LED through the glass bottom (0.5 cm distance to LED). The reaction progress was monitored by TLC or GC-FID and the reaction was
stopped, when all starting material was consumed, or no further progress was detected. Four equal reaction mixtures were united and
the solvent was removed at reduced pressure. Subsequently the products were purified by automated silica gel flash column
chromatography.
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tert-Butyl (2,4-dimethyl-6-nitrophenyl)carbamate (8b). According to the general procedure, after 24 h 8b was isolated as yellow solid
(43.1 mg, 0.162 mmol, 81%) using a gradient of 2% to 10% EtOAc/PE for silica gel flash column chromatography. 1H NMR (400 MHz,
CDCl3) δ 7.61 (s, 1H), 7.29 (s, 1H), 2.35 (s, 3H), 2.32 (s, 3H), 1.48 (s, 9H). 13C NMR (101 MHz, CDCl3) δ 152.7, 137.4, 136.8, 136.0,
127.7, 123.0, 81.3, 28.2, 20.7, 18.7. UV-Vis (ε, L∙mol-1∙cm-1): 268 nm (2949), 320 (1598). FT-IR (cm-1, neat, ATR): 3118, 2978, 1700,
1532. HRMS (+ESI) m/z: Calcd for C13H18N2O4Na 289.1159 [M + Na]+; Found 289.1167. Mp: 140-142 °C.
tert-Butyl (2,6-dimethyl-4-nitrophenyl)carbamate (10b). According to the general procedure, after 24 h 10b was isolated as yellow
solid (14.3 mg, 0.054 mmol, 27%) using a gradient of 2% to 9% EtOAc/PE for silica gel flash column chromatography.1H NMR (400
MHz, CDCl3) δ 7.94 (s, 2H), 6.01 (s, 1H), 2.36 (s, 6H), 1.50 (s, 9H). 13C NMR (101 MHz, CDC3l) δ 145.7, 140.2, 136.8, 123.2, 81.1,
28.2, 18.8. UV-Vis (ε, L∙mol-1∙cm-1): 290 nm (7793). FT-IR (cm-1, neat, ATR): 3244, 2926, 1685, 1502. HRMS (+ESI) m/z: Calcd for
C13H18N2O4Na 289.1159 [M + Na]+; Found 289.1164.
tert-Butyl (4-ethynyl-2-nitrophenyl)carbamate (11b). According to the general procedure, after 5.5 h 11b was isolated as yellow solid
(37.0 mg 0.141 mmol, 71%) using a gradient of 2% to 7% EtOAc/PE for silica gel flash column chromatography. 1H NMR (400 MHz,
CDCl3) δ 9.71 (s, 1H), 8.56 (m, 1H), 8.31 (m, 1H), 7.66 (m, 1H), 3.10 (s, 1H), 1.54 (s, 9H). 13C NMR (101 MHz, CDCl3) δ 151.9, 138.8,
136.2, 135.3, 129.5, 120.6, 115.9, 82.3, 81.1, 78.4, 28.2. UV-Vis absorption (ε, L∙mol-1∙cm-1): 373 nm (3284). FT-IR (cm-1, neat, ATR):
3388, 3287, 2983, 2929, 1729, 1503. HRMS (+ESI) m/z: Calcd for C13H14N2O4Na 285.0846 [M + Na]+; Found 285.0852. Mp: 112-113
°C.
tert-Butyl (2-nitro-4-vinylphenyl)carbamate (12b). According to the general procedure, after 1 h 12b was isolated as yellow solid (8.1
mg, 0.031 mmol, 15%) using a gradient of 2% to 5% EtOAc/PE for silica gel flash column chromatography. 1H NMR (400 MHz, CDCl3) δ
9.64 (s, 1H), 8.52 (m, 1H), 8.18 (m, 1H), 7.66 (m, 1H), 6.66 (dd, J = 17.6, 10.9 Hz, 1H), 5.77 (d, J = 17.6 Hz, 1H), 5.34 (d, J = 10.9 Hz,
1H), 1.54 (s, 9H). 13C NMR (101 MHz, CDCl3) δ 152.2, 136.0, 135.2, 134.2, 133.0, 131.8, 123.3, 120.8, 115.4, 80.0, 28.2. UV-Vis
absorption (ε, L∙mol-1∙cm-1): 258 nm (25766), 380 (3016). FT-IR (cm-1, neat, ATR): 3355, 2926, 1729, 1512. HRMS (+ESI) m/z: Calcd for
C13H16N2O4Na 287.1002 [M + Na]+; Found 287.1003. Mp: 64-67 °C.
tert-Butyl (2-nitro-4-phenoxyphenyl)carbamate (16b). According to the general procedure, after 6 h 12b was isolated as orange solid
(40.2 mg, 0.122 mmol, 61%) using an isocratic mixture of 1% EtOAc/PE for silica gel flash column chromatography. 1H NMR (300 MHz,
CDCl3) δ 9.49 (s, 1H), 8.52 (m, 1H), 7.78 (m, 1H), 7.41 – 7.29 (m, 3H), 7.20 – 7.12 (m, 1H), 7.00 (m, 2H), 1.54 (s, 9H). 13C NMR (75 MHz,
CDCl3) δ 156.3, 152.4, 151.4, 136.5, 131.5, 130.1, 126.9, 124.2, 122.5, 118.9, 114.8, 81.8, 28.2. UV-Vis absorption (ε, L∙mol-1∙cm-1):
383 nm (3502). FT-IR (cm-1, neat, ATR): 3369, 2926, 1726, 1510. HRMS (+ESI) m/z: Calcd for C17H18N2O5Na 353.1108 [M + Na]+; Found
353.1115. Mp: 81-81 °C.tert-Butyl (3-bromo-4-nitrophenyl)carbamate (18b-p), tert-Butyl (5-bromo-2-nitrophenyl)carbamate (18b-
o1) and tert-Butyl (3-bromo-2-nitrophenyl)carbamate (18b-o2). According to the general procedure, after 8 h 18b-p, 18b-o1 and 18b-
o2 were isolated as yellow solids (18b-p 9.4 mg, 0.030 mmol, 15%. 18b-o1 9.4 mg, 0.030 mmol, 15%. 18b-o2 18.3 mg, 0.058 mmol, 29%)
using a gradient of 2% to 15% EtOAc/PE for silica gel flash column chromatography. Spectral data for 18b-p: 1H NMR (400 MHz, CDCl3)
δ 7.94 (d, J = 9.0 Hz, 1H), 7.90 (d, J = 2.3 Hz, 1H), 7.38 (dd, J = 9.0, 2.4 Hz, 1H), 6.74 (s, 1H), 1.53 (s, 9H). 13C NMR (101 MHz, CDCl3)
δ 151.60, 143.60, 143.09, 127.36, 123.35, 116.52, 116.45, 82.34, 28.20. HRMS (+ESI) m/z: Calcd for C11H13BrN2O4Na 338.9951 [M +
Na]+; Found 338.9954. Spectral data for 18b-o: 1H NMR (400 MHz, CDCl3) δ 9.73 (s, 1H), 8.85 (d, J = 2.1 Hz, 1H), 8.06 (d, J = 9.0 Hz,
1H), 7.21 (dd, J = 9.0, 2.1 Hz, 1H), 1.55 (s, 9H). 13C NMR (101 MHz, CDCl3) δ 151.85, 136.83, 134.47, 131.35, 127.00, 125.10, 123.25,
82.46, 28.18.HRMS (+ESI) m/z: Calcd for C11H13BrN2O4Na 338.9951 [M + Na]+; Found 338.9948. Spectral data for 18b-o2: 1H NMR (400
MHz, CDCl3) δ 8.15 (dd, J = 8.2, 1.5 Hz, 1H), 7.36 (dd, J = 8.0, 1.6 Hz, 1H), 7.34 – 7.31 (m, 1H), 1.51 (s, 9H). 13C NMR (101 MHz, CDCl3)
δ 151.8, 133.0, 132.2, 128.1, 121.3, 114.2, 82.3, 28.2. UV-Vis absorption (ε, L∙mol-1∙cm-1): 275 nm (2607). FT-IR (cm-1, neat, ATR): 3417,
2929, 1737, 1490. HRMS (+ESI) m/z: Calcd for C11H13BrN2O4Na 338.9951 [M + Na]+; Found 338.9978.
tert-Butyl (2-bromo-6-nitrophenyl)carbamate (19b-o) and tert-Butyl (2-bromo-4-nitrophenyl)carbamate (19b-p). According to the
general procedure, after 10 h 19b-o and 19b-p were isolated as yellow solids (19b-o 10.5 mg, 0.033 mmol, 17%. 19b-p 6.3 mg, 0.020
mmol, 10%) using a gradient of 3% to 5% EtOAc/PE for silica gel flash column chromatography. Spectral data for 19b-o: 1H NMR (400
MHz, CDCl3) δ 8.46 – 8.39 (m, 2H), 8.18 (m, 1H), 7.32 (s, 1H), 1.56 (s, 9H). 13C NMR (101 MHz, CDCl3) δ 151.5, 142.3, 142.3, 128.0,
124.2, 118.2, 111.0, 82.7, 28.2. UV-Vis absorption (L∙mol-1∙cm-1): ε318 = 12161. FT-IR (cm-1, neat, ATR): 3408, 2930, 1729, 1504. HRMS
(+ESI) m/z: Calcd for C11H13BrN2O4Na 338.9951 [M + Na]+; Found 338.9949. Spectral data for 19b-p: 1H NMR (400 MHz, CDCl3) δ 7.88
(m, 1H), 7.82 (m, 1H), 7.18 (m, 1H), 6.95 (s, 1H), 1.49 (s, 9H). 13C NMR (101 MHz, CDCl3) δ 145.3, 137.1, 130.2, 125.9, 124.7, 120.9,
82.7, 28.1. UV-Vis absorption (ε, L∙mol-1∙cm-1): 307 nm (1787). FT-IR (cm-1, neat, ATR): 3157, 2986, 1700, 1532. HRMS (+ESI) m/z:
Calcd for C11H13BrN2O4Na 338.9951 [M + Na]+; Found 338.9952.
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Di-tert-butyl (2-nitro-1,4-phenylene)dicarbamate (22b). According to the general procedure, after 8.5 h 12b was isolated as orange
solid (41.2 mg, 0.117 mmol, 58%) using a gradient of 2% to 8% EtOAc/PE for silica gel flash column chromatography.1H NMR (300 MHz,
Chloroform-d) δ 9.45 (s, 1H), 8.44 (m, 1H), 8.33 (d, J = 2.6 Hz, 1H), 7.51 (m, 1H), 6.68 (s, 1H), 1.52 (d, J = 3.6 Hz, 18H). 13C NMR (75
MHz, CDCl3) δ 152.5, 152.4, 136.1, 132.9, 131.0, 126.1, 121.5, 114.8, 81.7, 28.3, 28.2. UV-Vis absorption (ε, L∙mol-1∙cm-1): 248 nm
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