General
The structures of products 2a-i were confirmed by analysis using spectral data (1H-NMR, 13C-NMR, FT-IR and HRMS). All spectral data and spectrum are represented in Additional file 1. The FT-IR spectra were measured by using KBr pellets. The NMR spectra were recorded on 600 MHz spectrometer and chemical shifts are reported relative to TMS. The mass spectra were recorded using a TOF-Q instrument was operated in positive ion mode. The melting points were measured in open capillary tubes without correction. All commercial reagents were synthesis grade and were used as received without additional purification. The procedures for preparation and purification of reported products are the same.
Preparation of 2-phenyl-4H-3,1-benzoxazin-4-one (2a)
Benzoyl chloride (0.349 ml, 3 mmol) was added to a stirred solution of anthranilic acid (0.411 g, 3 mmol) and triethylamine (0.460 mL, 3.3 mmol) in chloroform (10 mL). The mixture was stirred at room temperature for 2 hours, then, a yellow light colour solution of Cyanuric chloride (0.553 g, 3 mmol) in DMF (5 mL) was added to the stirred mixture. After 4 hours, the solvent was evaporated in vacuum and the residual was poured into distilled water (20 mL) and ice. Then, the filtrated solids were washed with a saturated solution of NaHCO3 (10 mL, two times) and distilled water (two times, 25 mL each). The white precipitate was recrystallized from a 1:1 diethyl ether/ethanol mixture to give the fine needle crystal of 2a (0.578 gr, yield: 86%, mp: 123–124°C). IR (KBr): vmax/cm−1 1764, 1622, 1603, 1541, 1266, 1077. 1H-NMR (DMSO): δ ppm 8.20 (ddd, J = 7.2, 1.2, 0.6 Hz, 2H), 8.15 (ddd, J = 7.2, 1.2, 0.6 Hz 1H), 7.95 (tdd, J = 8.4, 7.2, 1.2 Hz, 1H), 7.59-7.73 (m, 5H). 13C-NMR (DMSO): 159.4, 156.8, 146.7, 137.3, 133.2, 130.5, 129.5, 129.1, 128.5, 128.3, 127.4, 117.4. HRMS (ESI-TOF) m/z: [M+H]+ Calcd for C14H10NO2 (224.0707); Found 224.0706.
Preparation of 2-(3,5-dinitrophenyl)-4H-3,1-benzoxazin-4-one (2b)
3,5-dinitrobenzoyl chloride (0.692 gr, 3 mmol) is used for preparation of 2b using the same procedure as 2a. The sea-urchin shaped crystal was prepared (0.839 gr, yield: 89%, mp: 236–238°C) from crystallization of the gray powder of 2b in 1:1 ether/ethanol. IR (KBr): vmax/cm−1 1776, 1622, 1603, 1541, 1473, 1266, 1077. 1H-NMR (DMSO): δ ppm 9.13 (dd, J = 1.8, 1.2 Hz, 2H), 9.04 (dd, J = 1.4, 1.2 Hz, 1H), 8.23 (ddd, J = 7.8, 1.2, 0.6 Hz, 1H), 8.02 (ddd, J =8.4, 7.8,1.2 Hz, 1H), 7.90 (ddd, J =7.8, 1.2, 0.6 Hz, 1H) and 7.73 (ddd, J = 8.4, 7.8,1.2 Hz, 1H). 13C-NMR (DMSO): 158.6, 153.6, 149.1, 145.9, 137.7, 133.7, 130.2, 128.8, 127.9, 127.6, 122.1, 117.8. HRMS (ESI-TOF) m/z: [M+H]+ Calcd for C14H8N3O6 (314.0408); Found 314.0390.
Preparation of 2-(furan-2-yl)-4H-3,1-benzoxazin-4-one (2c)
For preparation of 2c, 2-Furoyl chloride was used by using the same procedure, as 2a. The product was isolated as a white crystalline solid (0.500 gr, yield: 78%, mp 106–108°C)
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IR (KBr): vmax/cm−1 1753, 1683, 1604, 1557, 1256, 1011. 1H-NMR (DMSO, δ ppm): 8.12 (ddd, J = 7.8, 1.2, 0.6 Hz, 1H), 8.09 (dd, J = 0.6, 1.8 Hz, 1H), 7.93 (ddd, J = 0.6, 1.2, 7.8 Hz, 1H), 7.66 (ddd, J = 7.8, 1.2, 7.8 Hz, 1 H), 7.59 (ddd, J = 7.8, 1.2, 7.8 Hz, 1H), 7.45 (dd, J = 3.6, 0.6 Hz, 1H), 6.80 (dd, J = 1.8, 3.6 Hz, 1H). 13C-NMR (DMSO): 158.7, 149.6, 148.4, 146.7, 144.6, 137.4, 128.8, 128.6, 127.1, 117.5, 113.4. HRMS (ESI-TOF) m/z: [M+H]+ Calcd for C12H8NO3 (214.0499); Found 214.0497.
Preparation of 2-(furan-3-yl)-4H-3,1-benzoxazin-4-one (2d)
3-Furoyl chloride was used for preparation 2d and the product was isolated as a white crystalline solid (0.506 gr, yield: 79%, mp 89–91°C). IR (KBr): vmax/cm−1 1764, 1644, 1632, 1603, 1258, 1069. 1H-NMR (DMSO, δ ppm): 8.55 (dd, J = 1.8, 0.6 Hz, 1H), 8.16 (ddd, J = 7.8, 1.2, 0.6 Hz, 1H), 7.92 (ddd, J = 7.8, 1.2, 0.6 Hz, 1H), 7.89 (dd, J = 1.8, 1.2 Hz, 1H), 7.64 (ddd, J = 7.8, 1.2, 0.6 Hz, 1H), 7.59 (ddd, J = 7.4, 7.2, 1.2 Hz, 1 H), 7.00 (dd, J = 1.8, 0.6 Hz, 1 H). 13C-NMR (DMSO): 159.2, 153.5, 147.4, 146.7, 145.9, 137.4, 128.8, 128.6, 126.93, 119.8, 117.3, 109.2. HRMS (ESI-TOF) m/z: [M+H]+ Calcd for C12H8NO3 (214.0499); Found 214.0478.
Preparation of 2-(N-phthaloylmethyl)-4H-3,1-benzoxazin-4-one (2e)
Benzoxazinone 2e was prepared from phthalimidoacetyl chloride (0.671 gr, 3 mmol) the same procedure as above and product was collected as a light yellow crystalline solid (0.752 gr, yield: 82%, mp 261–263°C). IR (KBr): vmax/cm−1 1776, 1688, 1591, 1529, 1258, 1088. 1H-NMR (DMSO): δ ppm 7.89-8.08 (m, 5 H, Ar-H), 7.87 (ddd, J = 7.8, 1.2, 0.6 Hz 1H, Ar-H), 7.60 (ddd, J = 7.8, 1.2, 6.6 Hz, 1 H, Ar-H), 7.23 (ddd, J = 6.6, 7.2, 1.2 Hz, 1 H, Ar-H), 3.77 (s, 2 H, CH2). 13C-NMR (DMSO): 167.9, 167.8, 165.7, 138.6, 135.2, 134.2, 132.0, 131.0, 124.5, 124.4, 122.3, 119.8, 52.7. HRMS (ESI-TOF) m/z: [M+H]+ Calcd for C17H11N2O4 (307.0713); Found 307.0720.
Preparation of 2-(4-bromophenyl)-4H-3,1-benzoxazin-4-one (2f)
Final product was isolated as a crystalline solid (0.802 gr, yield: 89%, mp: 184–185°C). IR (KBr): vmax/cm−1 1762, 1619, 1602, 1586, 1256, 1067. 1H-NMR (DMSO): δ ppm 8.16 (ddd, J = 7.2, 1.2, 0.6 Hz, 1H), 8.11 (ddd, J = 6.6, 1.8, 0.6 Hz, 2H), 7.96 (ddd, J = 8.4, 7.2, 1.2 Hz, 1H), 7.81 (ddd, J = 6.0, 1.2, 0.6 Hz, 2H), 7.73 (ddd, J = 8.4, 1.2, 0.6 Hz, 1H) and 7.64 (ddd, J = 7.8, 7.2, 0.6 Hz, 1H). 13C-NMR (DMSO): 159.2, 156.2, 154.1, 137.4, 132.6, 130.2, 129.8, 129.2, 128.6, 127.4, 127.1, 117.5. HRMS (ESI-TOF) m/z: [M+H]+ Calcd for C14H9BrNO2 (301.9811); Found 301.9807.
Preparation of 2-(styryl)-4H-3,1-benzoxazin-4-one (2g)
The product was collected as a yellow crystalline solid (0.600 gr, yield: 80%, mp: 148–149°C). IR (KBr): vmax/cm−1 1761, 1635, 1592, 1566, 1251, 1040. 1H-NMR (DMSO): δ ppm 7.78 (d, J = 16.2 Hz, 1H), 7.59 - 8.16 (m, 9H, Ar-H), 7.01 (d, J = 16.2 Hz, 1H). 13C-NMR (DMSO): 159.2, 157.3, 147.1, 141.6, 137.3, 134.9, 130.8, 129.4, 128.9, 128.7, 128.5, 127.1, 119.7, 117.3. HRMS (ESI-TOF) m/z: [M+H]+ Calcd for C16H12NO2 (250.0863); Found 250.0851.
Preparation of 2-(diphenylamino)-4H-3,1-benzoxazin-4-one (2h)
The result was isolated as a crystalline solid (83% yield, 0.780 gr, mp: 167–168°C). IR (KBr): vmax/cm−1 1745, 1619, 1582, 1489, 1267, 1072. 1H-NMR (DMSO): δ ppm 7.93 (ddd, J = 8.4, 1.8, 0.6 Hz, 1H), 7.69 (ddd, J = 8.4, 7.2, 1.8 Hz, 1H), 7.42-7.45 (m, 8 H, Ar-H), 7.29 - 7.32 (m, 2H, Ar-H), 7.26 (ddd, J = 7.8, 7.2, 0.6 Hz, 1H), 7.16 (ddd, J = 7.8, 1.2, 0.6 Hz, 1H). 13C-NMR (DMSO): 159.4, 153.1, 150.1, 142.7, 137.2, 128.5, 129.7, 128.0, 127.2, 125.1, 124.9, 114.1. HRMS (ESI-TOF) m/z: [M+H]+ Calcd for C20H15N2O2 (315.1128); Found 315.1131.
Preparation of 2-(4-nitrophenyl)-4H-3,1-benzoxazin-4-one (2i)
The procedure 2a was used for synthesis and workup of 2-(4-nitrophenyl)-4H-3,1-benzoxazin-4-one and the final product was gathered as a yellow wish crystalline solid (0.779 gr, yield: 86%, mp: 202–204). IR (KBr): vmax/cm−1 1766, 1607, 1589, 1522, 1493, 1251, 1082. 1H-NMR (DMSO): δ ppm 8.43 (ddd, J = 6.6, 1.8, 0.6 Hz, 2 H), 8.39 (ddd, J = 0.6, 7.8, 1.1 Hz, 1H), 8.18 (ddd, J = 0.6, 7.2, 1.2 Hz, 2H), 8.00 (ddd, J = 7.8, 1.2, 0.6 Hz, 1H), 7.71 (ddd, J = 8.4, 1.2, 7.2 Hz, 1H), 7.30 (ddd, J = 7.2, 7.8, 0.6 Hz, 1H). 13C-NMR (DMSO): 159.0, 156.2, 150.3, 146.7, 137.4, 136.4, 130.1, 129.8, 128.6, 127.2, 125.4, 119.1. HRMS (ESI-TOF) m/z: [M+H]+ Calcd for C14H9N2O4 (269.0557); Found 269.0554.