Example 4: Synthesis of 6-methyl-4-quinolone
1. In a dry reaction flask, 2-amino-5-methylacetophenone (99 mg, 0.67 mmol) was dissolved in toluene (8 mol) to form a homogeneous solution.
2. To the above solution, sodium hydride (60% oil dispersion, 80 mg, 2 mmol) was slowly added and the reaction mixture was stirred at room temperature for 30 min.
3. Ethyl formate (0.27 ml, 3.3 mmol) was added dropwise, and after addition, the reaction mixture was continued to be stirred at room temperature overnight.
4. After completion of the reaction, water (3 ml) was slowly added to the reaction solution and stirred for 5 minutes.
5. The reaction solution was adjusted to neutral with 10% hydrochloric acid solution and crystals were precipitated. 6.
6. The precipitated crystals were collected by filtration, washed with cold water (3 ml x 2) and dried to give 6-methyl-4-quinolone (56 mg, 53% yield).
Product Characterization:
1H-NMR (DMSO-d6, 400MHz): δ 2.40 (s, 3H), 5.99 (dd, J = 1.2, 7.3Hz, 1H), 7.41-7.49 (m, 2H), 7.84 (dd, J = 5.9, 7.3Hz, 1H), 7.87 (s, 1H), 11.7 (brs, 1H).
Mass spectrum (FD-MS, m/z): 159 (M+).
