Synthesis of 3-O-((N-ethyl, methyl) carbamoyl) acetophenone (7):Acetone (1000 ml) was added to a flask equipped with a reflux condenser and mechanical stirrer. 3'-Hydroxyacetophenone (G) (125 g, 0.919 mol) was added with stirring at room temperature to give a yellow transparent solution. Potassium carbonate (381 g, 2.757 mol, 3 eq.) and N-methyl-N-ethylcarbamoyl chloride (EMCC, 167.5 g, 1.379 mol, 1.5 eq.) were then added all at once. The addition funnel was rinsed with acetone (250 ml) and added to the reaction mixture. The reaction mixture was heated to reflux (55 °C). after 4 h, potassium carbonate (25.5 g, 0.18 mol, 0.2 eq.) and acetone (92 ml, 0.74 v/v) were added in a single addition. after 1 h, potassium carbonate (12.75 g, 0.09 mol, 0.1 eq.) was added in another single addition. Upon completion of the reaction, the reaction material was cooled to about 35°C and filtered under vacuum through a sintered funnel. The solids were discarded and the mother liquor was concentrated to give the crude product (7) as a red liquid. Yield:229 g, yield 112.74%.HPLC purity:96.71%. Sulfated ash:0.4%.1H NMR (δ ppm): 1.41-1.56 (2×t, 3H, N-CH2CH3), 2.6 (s, 3H, COCH3), 3.00 and 3.09 (2×s, 3H, N-CH3), 3.38-3.53 (2×q, 2H, N-CH2CH3), 7.32 (d, 1H, Ar- H), 7.46 (t, 1H, Ar-H), 7.69 (s, 1H, Ar-H), 7.78 (d, 1H, Ar-H).
