Step 1: Synthesis of 4-chloro-6-nitroquinazoline
To a solution of toluene (200 mL) containing 6-nitroquinazolin-4-ol (9.00 g, 47.1 mmol) and triethylamine (TEA, 9.53 g, 94.2 mmol) was slowly added phosphorus oxychloride (POCl3, 5.2 mL, 56.8 mmol) at 25 °C. Subsequently, the reaction mixture was heated to 80 °C and stirred at this temperature for 3.0 hours. Upon completion of the reaction, the mixture was cooled to 25 °C and diluted with the addition of toluene (100 mL). The organic phase was separated, washed with ice water (50 mL), dried over anhydrous sodium sulfate (Na2SO4), filtered, and concentrated by decompression to afford the title compound 4-chloro-6-nitroquinazoline as a yellow solid (7.00 g, 64.2% yield).
The structure of the compound was confirmed by the following spectral data: 1H NMR (400 MHz, DMSO-d6) δ: 8.78 (s, 1H), 8.54 (d, J = 6.8 Hz, 1H), 8.39 (s, 1H), 7.87 (d, J = 12.4 Hz, 1H).
