Bromine → HCID 20377723, compound

Participants

Reaction Steps

g 20 of 5-carbomethoxy-2-benzyloxy-acetophenone, m.p. = 86°-88° C. dissolved in methylene chloride (ml 200) were reacted with bromine (9.8 g) at 10° C. for 15 minutes. After treatment with 10% sodium sulphite and water, the organic phase was evaporated to dryness. The residue, crystallized from isopropyl ether, gave 5-carbomethoxy-2-benzyloxy-ω-bromo-acetophenone (17 g), m.p. = 84°-86° C., which was dissolved in dimethylformamide (85 ml) and reacted with anhydrous potassium acetate (5.6 g) at 50° C. for 2 hours. After cooling, and dilution with water, the precipitate was filtered and washed with cold methanol so obtaining 5-carbomethoxy-2-benzyloxy-ω-acetoxy-acetophenone (12.9 g), m.p. = 86°-87° C., which was dissolved in tetrahydrofuran (40 ml) and ethanol (20 ml); few drops of concentrated HCl were added and then the solution was hydrogenated at atmospheric pressure and room temperature in the presence of 5% Pd/O (2.5g) to the theoretical hydrogen consumption. The mixture was filtered to remove the catalyst and the organic solution was evaporated to dryness so detaining crude 5-carbomethoxy-2-hydroxy-ω-acetoxy-acetophenone (9.2 g), which was dissolved in dioxane (20 ml) and pyridine (10 ml) and reacted with trans-cinnamoyl-chloride (9.4 g) at room temperature for 8 hours. The reaction mixture was diluted with water and acidified to pH 4. The precipitate was filtered, dried and dissolved in methyl-ethyl-ketone (100 ml); anhydrous K2CO3 (9.3 g) was added and the mixture was vigorously stirred under reflux for 5 hours.

Provenance & Evidence