Molecules 2019, 24, 3555
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1H-NMR (400 MHz, CDCl3):
δ
10.98 (br s, 1H, NH), 8.62 (d, 1H, J = 8.6 Hz, ArH), 7.83 (s, 1H, ArH),
7.35 (d, 1H, J = 8.6 Hz, ArH), 4.38 (q, 2H, J = 7.1 Hz, OCH2CH3), 2.41 (q, 2H, J = 7.5 Hz, CH2CH2CH3),
2.33 (s, 3H, ArCH3), 1.78 (sextet, 2H, J = 7.5 Hz, CH2CH2CH3), 1.42 (t, 3H, J = 7.1 Hz, OCH2CH3), 1.01
(t, 3H, J = 7.5 Hz, CH2CH2CH3); 13C-NMR (101 MHz, CDCl3):
δ 171.9, 168.4, 139.3, 135.3, 131.7, 130.8,
120.3, 114.9, 61.3, 40.6, 20.7, 19.0, 14.2, 13.8; HRMS (ESI): m/z [M + H]+ calcd. for C14H19NO3: 250.1443,
found: 250.1441.
(
±
)-2-Ethoxy-6-methyl-2-phenyl-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-one (18d): 249 mg (88%, method 1)
as white crystals, m.p. 117–118 ◦C; IR (thin film): 3249, 1662, 1602 cm−1; 1H-NMR (400 MHz, CDCl3):
11.98 (br s, 1H, NH), 8.82 (d, 1H, J = 8.5 Hz, ArH), 8.05 (d, 2H, J = 6.8 Hz, ArH), 7.89 (s, 1H, ArH),
7.58-7.47 (complex, 3H), 7.42 (d, 1H, J = 8.5 Hz, ArH), 4.42 (q, 2H, J = 7.1 Hz, OCH2CH3), 3.36 (s, 3H,
δ
ArCH3), 1.44 (q, 3H, J = 7.1 Hz, OCH2CH3); 13C-NMR (101 MHz, CDCl3):
δ 168.9, 165.5, 139.5, 135.4,
135.1, 132.1, 131.8, 131.0, 128.8, 127.3, 120.4, 115.4, 61.5, 20.8, 14.3; HRMS (ESI): m/z [M + H]+ calcd. for
C17H17NO3: 284.1287, found: 284.1283.
(
±
)-2-Ethoxy-2-methyl-7-nitro-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-one (20a): 212 mg (84%, method 1)
and 219 mg (87%, method 2) as light tan crystals, m.p. 108–109 ◦C; IR (thin film): 3270, 1702, 1604,
1538, 1350 cm−1; 1H-NMR (400 MHz, CDCl3):
11.16 (br s, 1H, NH), 9.60 (d, 1H, J = 2.4 Hz, ArH), 8.20
(d, 1H, J = 8.8 Hz, ArH), 7.87 (dd, 1H, J = 8.8, 2.4 Hz, ArH), 4.45 (q, 2H, J = 7.1 Hz, OCH2CH3), 2.28 (s,
δ
3H, CH3), 1.46 (t, 3H, J = 7.1 Hz, OCH2CH3); 13C-NMR (101 MHz, CDCl3):
δ 169.2, 166.9, 151.2, 142.2,
131.9, 119.3, 116.4, 115.2, 62.5, 25.5, 14.1; HRMS (ESI): m/z [M + H]+ calcd. for C11H12N2O5: 253.0825,
found: 253.0824.
(
±
)-2-Ethoxy-2-ethyl-7-nitro-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-one (20b): 229 mg (86%, method 1) and
234 mg (88%, method 2) as light tan crystals, m.p. 74–75 ◦C; IR (thin film): 3273, 1694, 1600, 1538,
1349 cm−1; 1H-NMR (400 MHz, CDCl3):
11.18 (br s, 1H, NH), 9.65 (d, 1H, J = 2.4 Hz, ArH), 8.20 (d,
δ
1H, J = 8.8 Hz, ArH), 7.86 (dd, 1H, J = 8.8, 2.4 Hz, ArH), 4.45 (q, 2H, J = 7.1 Hz, OCH2CH3), 2.53 (q, 2H,
J = 7.5 Hz, CH2CH3), 1.46 (t, 3H, J = 7.1 Hz, OCH2CH3), 1.30 (t, 3H, J = 7.5 Hz, CH2CH3); 13C-NMR
(101 MHz, CDCl3):
δ 173.1, 166.9, 151.2, 142.5, 131.9, 119.3, 116.3, 115.3, 62.4, 31.6, 14.1, 9.3; HRMS (ESI):
m/z [M + H]+ calcd. for C12H14N2O5: 267.0981, found: 267.0977.
(
±
)-2-Ethoxy-2-propyl-7-nitro-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-one (20c): 238 mg (85%, method 1) and
245 mg (88%, method 2) as light tan crystals, m.p. 66–67 ◦C; IR (thin film): 3270, 1697, 1604, 1538,
1349 cm−1; 1H-NMR (400 MHz, CDCl3):
11.17 (br s, 1H, NH), 9.65 (d, 1H, J = 2.4 Hz, ArH), 8.20 (d,
δ
1H, J = 8.8 Hz, ArH), 7.86 (dd, 1H, J = 8.8, 2.4 Hz, ArH), 4.45 (q, 2H, J = 7.1 Hz, OCH2CH3), 2.47 (q, 2H,
J = 7.4 Hz, CH2CH2CH3), 1.81 (sextet, 2H, J = 7.4 Hz, CH2CH2CH3), 1.46 (t, 3H, J = 7.1 Hz, OCH2CH3),
1.04 (t, 3H, J = 7.4 Hz, CH2CH2CH3); 13C-NMR (101 MHz, CDCl3):
δ 172.3, 166.9, 151.2, 142.5, 131.9,
119.3, 116.3, 115.3, 62.4, 40.4, 18.8, 14.1, 13.7; HRMS (ESI): m/z [M + H]+ calcd. for C13H16N2O5:
281.1138, found: 281.1140.
(
±
)-2-Ethoxy-7-nitro-2-phenyl-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-one (20d): 283 mg (90%, method 1) as
off-white crystals, m.p. 180–181 ◦C; IR (thin film): 3257, 1673, 1651, 1600, 1538, 1346 cm−1; 1H-NMR
(400 MHz, CDCl3): 11.62 (br s, 1H, NH), 9.31 (d, 1H, J = 2.4 Hz, ArH), 8.20 (d, 1H, J = 8.8 Hz, ArH),
δ
8.03 (dd, 1H, J = 8.8, 2.4 Hz, ArH), 7.97 (d, 2H, J = 7.4 Hz, ArH, 7.69 (t, 1H, J = 7.4 Hz, ArH), 7.61 (t,
2H, J = 7.4 Hz, ArH), 4.38 (q, 2H, J = 7.1 Hz, OCH2CH3), 1.33 (t, 3H, J = 7.1 Hz, OCH2CH3); 13C-NMR
(101 MHz, CDCl3):
δ 166.7, 165.7, 150.6, 141.0, 134.1, 133.1, 132.7, 129.5, 127.7, 1239, 118.2, 116.0, 62.6,
14.3; HRMS (ESI): m/z [M + H]+ calcd. for C16H14N2O5: 315.0981, found: 315.0975.
(±
)-7-Chloro-2-ethoxy-2-methyl-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-one (21a): 203 mg (84%, method 1) as
white crystals, m.p. 75–76 ◦C; IR (thin film): 3262, 1681, 1578 cm−1; 1H-NMR (400 MHz, CDCl3):
δ
10.70 (br s, 1H, NH), 8.43 (d, 1H, J = 2.2 Hz, ArH), 7.92 (d, 1H, J = 8.6 Hz, ArH), 7.23 (dd, 1H, J = 8.6,
2.2 Hz, ArH), 4.83 (q, 2H, J = 7.1 Hz, OCH2CH3), 2.15 (s, 3H, CH3), 1.34 (t, 3H, J = 7.1 Hz, OCH2CH3);
13C-NMR (101 MHz, CDCl3):
δ
169.1, 167.7, 142.4, 140.8, 131.8, 122.6, 120.1, 113.2, 61.6, 25.5, 14.2;
HRMS (ESI): m/z [M + H]+ calcd. for C11H1235ClNO3: 242.0584, found: 242.0582.