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HETEROCYCLES, Vol. 91, No. 7, 2015
1H). 13C-NMR (CDCl3) Gꢀꢁ118.1, 122.0, 123.8, 125.5, 127.3, 127.6, 130.3, 130.8, 135.2, 138.4, 144.4,
+
146.4, 146.7, 158.2, 182.7. HR-MS (ESI) m/z: Calcd for C15H9N2O2 [(M+H) ]: 249.0664. Found:
249.0669.
2,8-Dimethylindolo[2,1-b]quinazoline-6,12-dione (1b): Yellow solid. Mp 251-253 °C. IR (CHCl3):
1724, 1694 cm-1. 1H-NMR (CDCl3) G: 2.44 (s, 3H), 2.54 (s, 3H), 7.55 (d, J = 8.6 Hz, 1H), 7.63 (d, J = 8.0
Hz, 1H), 7.68 (s, 1H), 7.89 (t, J = 8.1 Hz, 1H), 8.20 (s, 1H), 8.46 (d, J = 8.6 Hz, 1H). 13C-NMR (CDCl3)
Gꢀꢁ21.2, 21.7, 117.8, 122.2, 123.6, 125.5, 127.3, 130.6, 136.3, 137.4, 138.9, 141.2, 144.1, 144.4, 144.7,
158.1, 182.8. HR-MS (ESI) m/z: Calcd for C17H13N2O2 [(M+H)+]: 277.0977. Found: 277.0977.
2,8-Dimethoxyindolo[2,1-b]quinazoline-6,12-dione (1c): Yellow solid. Mp 281-283 °C (EtOH). IR
(CHCl3): 1730, 1687 cm-1. 1H-NMR (CDCl3) Gꢀ 3.88 (s, 3H), 3.97 (s, 3H), 7.29 (dd, J = 2.9, 8.6 Hz, 1H),
7.36 (d, J = 3.5 Hz, 1H), 7.38 (dd, J = 2.9, 9.2 Hz, 1H), 7.80 (d, J = 2.9 Hz, 1H), 7.92 (d, J = 8.6 Hz, 1H),
8.49 (d, J = 9.2 Hz, 1H). 13C-NMR (CDCl3) Gꢀꢁ56.1, 56.2, 108.2, 108.4, 119.2, 123.4, 124.2, 124.9, 125.4,
132.5, 140.3, 140.9, 143.1, 157.6, 158.8, 161.4, 182.6. HR-MS (ESI) m/z: Calcd for C17H12N2NaO4
[(M+Na)+]: 331.0695. Found: 331.0693.
2,8-Dichloroindolo[2,1-b]quinazoline-6,12-dione (1d): Yellow solid. Mp 287-289 °C. IR (CHCl3): 1736,
1689 cm-1. 1H-NMR (CDCl3) G: 7.75 (dd, J = 2.3, 8.6 Hz, 1H), 7.80 (dd, J = 2.3, 8.6 Hz, 1H), 7.87 (d, J =
2.3 Hz, 1H), 7.96 (d, J = 8.6 Hz, 1H), 8.39 (d, J = 2.5 Hz, 1H), 8.57 (d, J = 8.6 Hz, 1H). 13C-NMR
(CDCl3) Gꢀꢁ119.4, 123.2, 124.9, 125.4, 127.3, 132.3, 133.7, 135.8, 137.1, 137.9, 144.1, 144.3, 145.1,
156.9, 181.2. HR-MS (ESI) m/z: Calcd for C15H7Cl2N2O2 [(M+H)+]: 316.9885, 318.9855. Found:
316.9882, 318.9843.
General procedure for the oxidation of 4: PCC (1.1 mmol) was added to a stirred solution of 4 (1
mmol) in DMF (5 mL) at 100 °C (pre-heated oil bath) and the mixture was stirred at 100 °C for 0.5 h.
After cooling, the resulting mixture was added to 10% aqueous HCl solution, extracted with AcOEt (100
mL), washed with brine, and dried over MgSO4. The solvent was removed, and the residue was purified
by silica gel column chromatography with CH2Cl2 to give 2.
1
1-Methylindole-3-carbaldehyde (2b): Colorless solid. Mp 69-70 °C. IR (CHCl3): 1659 cm-1. H-NMR
(DMSO-d6) Gꢀꢁ3.85 (s, 3H), 7.23 (t, J = 8.0 Hz, 1H), 7.29 (t, J = 7.5 Hz, 1H), 7.53 (d, J = 8.0 Hz, 1H),
8.07 (d, J = 8.0 Hz, 1H), 8.22 (s, 1H), 9.86 (s, 1H). 13C-NMR (CDCl3) G: 33.9, 111.5, 117.5, 121.4, 123.0,
124.0, 125.1, 138.2, 142.1, 184.9. HR-MS (ESI) m/z: Calcd for C10H9NNaO [(M+Na)+]: 182.0582.
Found: 182.0585.
1-Methoxyindole-3-carbaldehyde (2c): Colorless solid. Mp 50-51 °C. IR (CHCl3): 1658 cm-1. 1H-NMR
(CDCl3) Gꢀꢁ4.19 (s, 3H), 7.33 (t, J = 8.0 Hz, 1H), 7.38 (t, J = 7.5 Hz, 1H), 7.48 (d, J = 8.0 Hz, 1H), 7.88 (s,
1H), 8.30 (d, J = 7.4 Hz, 1H), 9.99 (br s, 1H). 13C-NMR (CDCl3)ꢁGꢀ 66.9, 108.8, 114.2, 121.8, 122.2,
123.6, 124.7, 131.8, 132.8, 184.2. HR-MS (ESI) m/z: Calcd for C10H10NO2 [(M+H)+]: 176.0712. Found: