反応 #1077768
ord-e8350c947ae442baae5232ca0b586247
反応条件
後処理
- 1乾燥4-Arm PEG (MW 20 Kda, 20 g, ˜1 mmol) (Shearwater Corporation) was azeotropically dried in vacuo with CHCl3 (3×200 ml)
- 2workup.DISSOLUTIONwas redissolved in CH2Cl2 (250 ml)
- 3温度to reflux under of argon for 17 hours
- 4濃縮The mixture was then concentrated in vacuo
- 5workup.DISSOLUTIONthe residual syrup was dissolved in toluene (˜200 ml)
- 6ろ過filtered
- 7その他The toluene was removed in vacuo at about 45° C.
- 8workup.ADDITIONthe residue was treated with 5 ml of CH2Cl2
- 9その他triturated with 2-propanol (300 ml)
- 10ろ過The resulting precipitate was collected by vacuum filtration
- 11その他dried in vacuo
実験手順
4-Arm PEG (MW 20 Kda, 20 g, ˜1 mmol) (Shearwater Corporation) was azeotropically dried in vacuo with CHCl3 (3×200 ml) and was redissolved in CH2Cl2 (250 ml). To this clear solution was added artelinic acid (3.30 g, 7.88 mmol), N,N-dimethylaminopyridine (DMAP) (catalytic amount), and 1-hydroxybenzotriazole (HOBT) (0.680 g, 5.03 mmol). N,N-dicyclohexylcarbodiimide (DCC) (1.74 g, 8.43 mmol in about 10 ml of CH2Cl2) was then added and the mixture was allowed to reflux under of argon for 17 hours. The mixture was then concentrated in vacuo and the residual syrup was dissolved in toluene (˜200 ml) and filtered. The toluene was removed in vacuo at about 45° C. and the residue was treated with 5 ml of CH2Cl2 and triturated with 2-propanol (300 ml). The resulting precipitate was collected by vacuum filtration and dried in vacuo to obtain a pure water-soluble product (18.5 g, 92% yield) with >95% substitution as indicated by 1H NMR. Partial 1H NMR data (CDCl3, 300 MHz): δ 0.94 (s, 12H, C9—CH3), 0.95 (s, 12H, C6—CH3), 1.44 (s, 12H, C3—CH3), 2.68 (m, 4H, H-9), 3.63 (bs, 1818H, PEG backbone), 4.45 (t, 8H, J 4.4 Hz, PEG—OCH2CH2O—COAr), 4.56 (d, 4H, J 13.1 Hz, OCHAHB—Ar), 4.91-4.96 (m, 8H, H-10 overlapped with OCHAHB—Ar), 5.44 (s, 4H, H-12), 7.37 (d, 4H, J 7.8 Hz, Ar), 8.01 (d, 4H, Ar).