溴代异丁酸乙二醇酯溴代异丁酸羟乙醇酯

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Anhydrous ethylene glycol (301.3 g, 4.85 mol) and triethylamine (28 mL, 200 mmol) were diluted with dry tetrahydrofuran (100 mL). The reaction mixture was cooled in an ice-water bath and a solution of α-bromoisobutyryl bromide (12 mL, 97.1 mmol) in dry tetrahydrofuran (50 mL) was slowly added while stirring. The mixture was stirred in the cooling bath for 1 h and then at room temperature for 16 h. The reaction mixture was then poured into water (800 mL) and extracted with dichloromethane (6×100 mL). The organic fractions were combined, washed with acidic water (pH=4), dried over MgSO4 and evaporated to dryness to afford 17.477 g (yield=85.3%) of a very pale yellow liquid. 1H NMR (CDCl3, δ, ppm): 4.30-4.19 (m, 2H), 3.86-3.75 (m, 2H), 2.86-2.47 (broad peak, 1H, OH), 1.89 (s, 6H). 13C NMR (CDCl3, δ): 171.95, 67.40, 60.63, 55.89, 30.72. The reaction mixture was cooled in an ice-water bath The mixture was stirred in the cooling bath for 1 h extracted with dichloromethane (6×100 mL) washed with acidic water (pH=4) dried over MgSO4 evaporated to dryness to afford 17.477 g (yield=85.3%) of a very pale yellow liquid

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 2-Hydroxyethyl-2-bromo-2-methylpropionate (initiator 9) (0.187 g, 0.887 mmol) and 3-(2,5-Dioxo-2,5-dihydro-pyrrol-1-yl)-propionic acid (0.300 g, 1.77 mmol) were dissolved in dichloromethane (10 ml) under nitrogen in a 25 ml round-bottomed flask. Then N,N′-Dicyclohexylcarbodiimide (DCC) (0.366 g, 1.77 mmol) was added to the solution. After one day at room temperature, very low conversion was observed and 0.5 ml (9.50×10−3 mmol) of a solution of 4-dimethylaminopyridine (DMAP) in dichloromethane (Conc.DMAP=19 mmol/l) was added. Total conversion was then achieved in 12 hours and the solvent was removed under reduced pressure. The solid residue was extracted with 3×50 ml of petroleum ether and the petroleum ether was removed by evaporation under vacuum in order to isolate a colourless oil (0.270 g, 0.745 mmol, 84%). The pale pink residue was extracted with 3×50 ml of diethylether, but TLC (CH2Cl2/AcOEt 9:1) revealed that only traces of the ester were present. An analytical pure sample was obtained by flash chromatography (cc, SiO2, Pet. Ether/Et2O 3:1). Total conversion was then achieved in 12 hours the solvent was removed under reduced pressure The solid residue was extracted with 3×50 ml of petroleum ether the petroleum ether was removed by evaporation under vacuum in order

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Ethylene glycol (279 g, 4500 mmol) and Et3N (3.34 g, 33.0 mmol) were poured in a 2-necked round bottom flask. To this was added dropwise and a solution of 2-bromoisobutryl bromide (6.90 g, 30.0 mmol) in anhydrous THF (50 mL) at room temperature over ca. 1 h. The colourless solution was stirred overnight, then diluted in 500 mL of water and extracted with 3×200 mL of a mixture of Et2O/CH2Cl2 (4:1). The organic layers, reunited, were washed with 2×200 mL of water and dried over MgSO4. Evaporation of the solvent at reduced pressure (rotavapor, without heating) gave a pale yellow liquid. The latter was dissolved in ca. 30 mL of CH2Cl2 then 10 g of SiO2 were added and the solvent evaporated again until a white powder was obtained. This was poured in a column packed with SiO2, (ca 15 cm depth) previously eluted with petroleum ether/Et2O 5:1 and purified by column chromatography (elute with petroleum ether/Et2O 5:1) to eliminate the impurities. The desired product, using this solvent mixture, has an Rf ˜0 (stays on the bottom of the TLC plate). When the impurities have been eliminated, the column was eluted with 100% Et2O, to give a colourless liquid. Yield 82%. IR ν(N—H) 3388 cm−1 (broad); ν(C═O) 1731 cm−1. 1H NMR (CDCl3) δ=1.97 (s, 6H, CH3); 3.89 (t, J=4.6 Hz; 2H, OCH2CH2OH); 4.33 (t, J=4.6 Hz; 2H, OCH2CH2OH). 13C NMR (CDCl3) δ=30.45 (2C, CH3), 55.55 (1C, C(CH3)2Br); 60.66 (1C, OCH2CH2OH); 65.90 (1C, OCH2CH2OH); 171.69 (1C, C═O). To this was added dropwise extracted with 3×200 mL of a mixture of Et2O/CH2Cl2 (4:1) were washed with 2×200 mL of water dried over MgSO4 Evaporation of the solvent at reduced pressure (rotavapor, without heating) gave a pale yellow liquid the solvent evaporated again until a white powder was obtained This was poured in a column previously eluted with petroleum ether/Et2O 5:1 purified by column chromatography (elute with petroleum ether/Et2O 5:1) the column was eluted with 100% Et2O to give a colourless liquid

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: Ethylene glycol (279 g, 4500 mmol) and Et3N (3.34 g, 33.0 mmol) were poured in a 2-necked round bottom flask. To this was added dropwise and a solution of 2-bromoisobutryl bromide (6.90 g, 30.0 mmol) in anhydrous THF (50 mL) at room temperature over ca. 1 h. The colourless solution was stirred overnight, then diluted in 500 mL of water and extracted with 3×200 mL of a mixture of Et2O/CH2Cl2 (4:1). The organic layers, reunited, were washed with 2×200 mL of water and dried over MgSO4. Evaporation of the solvent at reduced pressure (rotavapor, without heating) gave a pale yellow liquid. The latter was dissolved in ca. 30 mL of CH2Cl2 then 10 g of SiO2 were added and the solvent evaporated again until a white powder was obtained. This was poured in a column packed with SiO2, (ca 15 cm depth) previously eluted with petroleum ether/Et2O 5:1 and purified by column chromatography (elute with petroleum ether/Et2O 5:1) to eliminate the impurities. The desired product, using this solvent mixture, has an Rf˜0 (stays on the bottom of the TLC plate). When the impurities have been eliminated, the column was eluted with 100% Et2O, to give a colourless liquid. Yield 82%. IR ν(N—H) 3388 cm− (broad); ν(C═O) 1731 cm−1. 1H NMR (CDCl3) δ=1.97 (s, 6H, CH3); 3.89 (t, J=4.6 Hz; 2H, OCH2CH2OH); 4.33 (t, J=4.6 Hz; 2H, OCH2CH2OH). 13C NMR (CDCl3) δ=30.45 (2C, CH3), 55.55 (1C, C(CH3)2Br); 60.66 (1C, OCH2CH2OH); 65.90 (1C, OCH2CH2OH); 171.69 (1C, C═O). To this was added dropwise extracted with 3×200 mL of a mixture of Et2O/CH2Cl2 (4:1) were washed with 2×200 mL of water dried over MgSO4 Evaporation of the solvent at reduced pressure (rotavapor, without heating) gave a pale yellow liquid the solvent evaporated again until a white powder was obtained This was poured in a column previously eluted with petroleum ether/Et2O 5:1 purified by column chromatography (elute with petroleum ether/Et2O 5:1) the column was eluted with 100% Et2O to give a colourless liquid