Preparation of 3-Formyl-N-phenylbenzenesulfonamide (5)
Pyridine (96 mL, 1.5 mol) was added to a solution of aniline (118 mL, 1.3 mol) in EA (600 mL), and the mixture was stirred at 0–5 °C. Then the solution of 3-formylbenzenesulfonyl chloride 4 (200 g, 1.0 mol) in EA (400 mL) was added slowly to the reaction mixture over 1.5 h while maintaining the reaction temperature below 5 °C. The solution was stirred at 0–5 °C for 1 h and then at ambient temperature for 19 h. When the reaction was deemed to be complete with no 4 detected by TLC, the reaction mixture was washed with a 10% aqueous solution of hydrochloric acid (two portions of 500 mL) followed by washing with water (500 L), 5% aqueous solution of sodium bicarbonate (500 mL), and then brine (500 mL); dried with sodium sulfate anhydrous; filtered; and concentrated to afford yellow solid 3-formyl-N-phenylbenzenesulfonamide (242 g, 93%). Crude 5was used directly into next step. A sample of purified 5 as a white solid was analyzed as follows.
1H NMR (CDCl3, 400 MHz) δ = 10.38 (s, 1H), 10.00 (s, 1H), 8.29 (s, 1H), 8.05 (d, J = 7.8 Hz, 1H), 8.00 (d, J = 7.8 Hz, 1H), 7.62 (t, J = 7.8 Hz, 1H), 7.27–7.23 (m, 2H), 7.16–7.01 (m, 3H).
1H NMR (CDCl3, 400 MHz) δ = 10.38 (s, 1H), 10.00 (s, 1H), 8.29 (s, 1H), 8.05 (d, J = 7.8 Hz, 1H), 8.00 (d, J = 7.8 Hz, 1H), 7.62 (t, J = 7.8 Hz, 1H), 7.27–7.23 (m, 2H), 7.16–7.01 (m, 3H).
KHAJURAHO, MADYA PRADESH, INDIA
