反应详情

温度

75 °C

2,5-Dimethylphenol (6.1 g, 0.05 mol) and ethyl bromobutyrate were dissolved in 60 ml of N,N-Dimethylacetamide (DMAC). Potassium carbonate (11 g) and potassium iodide 0.5 g (0.003 mol) were added to this solution. The mixture was stirred at 70-80° C. for 24 hours. The filtrate was added to distilled water (200 ml). An oily precipitate formed and was extracted with methylene chloride (100 ml). The organic layer was washed with 5% sodium carbonate (3×150 ml), dried over anhydrous sodium sulfate, and concentrated to give al oily residue. The oil was dissolved in ethanol (5 ml). The solution was mixed with 2N sodium hydroxide (30 ml). The mixture was stirred at 70-80° C. until the ester was hydrolyzed (determined by HPLC). The solution was acidified with 3N hydrochloride to pH 1 to form a precipitate. The precipitate was collected by filtration and dissolved in 4% sodium bicarbonate. Insoluble materials were removed by filtration. The filtrate was acidified to pH 1 to form a precipitate. The precipitate was collected by filtration and air-dried. 6.6 g of 4-(2,5-dimethylphenoxy) butyric acid was recovered. Melting point: 63-65° C. Combustion analysis: % C. 69.21 (calcuated), 69.04 (found); % H, 7.74 (calculated); 7.49 (found). 1H NMR Analysis (d6-DMSO). δ 6.98, d, 1H; 6.71, s, 1H; 6.62, d, 1H; 3.94, t, 2H; 2.40, t, 2H; 2.24, s, 3H; 2.09, s, 3H; 1.95, p, 2H.

1. additionThe filtrate was added
2. distillationto distilled water (200 ml)
3. customAn oily precipitate formed
4. extractionwas extracted with methylene chloride (100 ml)
5. washThe organic layer was washed with 5% sodium carbonate (3×150 ml)
6. dry with materialdried over anhydrous sodium sulfate
7. concentrationconcentrated
8. customto give al oily residue
9. customto form a precipitate
10. filtrationThe precipitate was collected by filtration
11. dissolutiondissolved in 4% sodium bicarbonate
12. customInsoluble materials were removed by filtration
13. customto form a precipitate
14. filtrationThe precipitate was collected by filtration
15. customair-dried
16. custom6.6 g of 4-(2,5-dimethylphenoxy) butyric acid was recovered