||With hydrogen bromide; acetic acid; zinc dibromide; at 90℃; for 16.5h;
||In a first step, to a mixture of paraformaldehyde (16.7 g, 556.3 mmol) and triethylbenzene (1, 10 mL, 53.1 mmol) in HBr/AcOH (100 mL, 30 wt %) zinc bromide (19.7 g, 87.5 mmol) was slowly added at room temperature. The mixture was heated to 90 C for 16.5 h, during which time white crystals were formed. The reaction was cooled to room temperature, and the white solid was filtered off, washed with water, and dried under vacuum overnight to give 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene (22.8 g, 51.7 mmol, 97%) as a white solid. In a second step, to a suspension of potassium phthalimide (8.4 g, 45.4 mmol) in dry DMSO (75 mL) 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene (5.0 g, 11.3 mmol) was added at room temperature, under nitrogen atmosphere. The reaction mixture was heated to 84 C for 8 h; the solution obtained was cooled to 0 C, and the formation of a white solid was observed. After 1 h at room temperature, the solid was filtered off, dissolved in water (100 mL), and extracted with CH2Cl2 (2 × 100 mL). The combined organic layers were washed with water (2 × 50 mL), dried over Na2SO4, and concentrated to give 1,3,5-tris(phthalimidomethyl)-2,4,6-triethylbenzene (4.88 g, 7.63 mmol, 67%) as white crystals. Then the mother liquor was poured into water (200 mL), and the white precipitate formed was filtered off. The solid was dissolved in CH2Cl2 (100 mL), washed with water (3 × 50 mL), and dried over Na2SO4. Evaporation of the organic solvent gave a crude (2.69 g) which was purified by flash column chromatography on silica gel (hexane/EtOAc, 1/1, v/v) to afford a second amount of 1,3,5-tris(phthalimidomethyl)-2,4,6-triethylbenzene (1.45 g, 2.27 mmol, 20%). In the thrid step, to a suspension of 1,3,5-tris(phthalimidomethyl)-2,4,6-triethylbenzene (3.2 g, 5.0 mmol) in EtOH/toluene 2:1 v/v (18 mL) hydrazine hydrate (0.98 mL, 30.8 mmol) was added at room temperature under nitrogen atmosphere. The reaction mixture was refluxed for 20 h, and during this time a white solid was formed. The reaction was cooled to room temperature, and the white solid was filtered off, dissolved in a 40% aqueous solution of KOH (120 mL), and extracted with CHCl3 (3 × 150 mL). The combined organic layers were washed with water (3 × 150 mL) and dried over Na2SO4. Evaporation of the organic solvent gave 2 (0.973 g, 3.90 mmol, 78%) as a white solid. Mp 138-140 C; 1H NMR (0.1 mol dm-3 in CDCl3, 200 MHz) delta: 3.87 (bs, 6H), 2.82 (q, 6H), 1.26 (bs, 6H), 1.23 (t, 9H). 13C NMR (CDCl3, 50 MHz) delta: 140.3, 137.4, 39.6, 22.5, 16.8.
||With hydrogen bromide; acetic acid; zinc dibromide; at 20 - 90℃; for 16.5h;
||Add paraformaldehyde (33.5g, 1.11mol) and <strong>[102-25-0]1,3,5-triethylbenzene</strong> (20ml, 106.2mmol) to 100ml of HBr / AcOH (30wt%, mass ratio 3: 7) solution,Slowly add zinc bromide (39.4g, 175mmol) at room temperature,The reaction solution was reacted at 90 C for 16.5 hours.The reaction liquid was cooled to room temperature, and a white solid precipitated, and the solid was filtered out.Wash three times with distilled water and vacuum dry to obtain 45.0g of product, yield 96%,
||With hydrogen bromide; zinc dibromide; In acetic acid;
|| Compound I was synthesized from commercially available 1,3,5- triethylbenzene. Compounds 5, 6 and 7 were prepared as previously described in Vacca, A. et al, J. Am. Chem. Soc. 2004, 126:16456, Nativi, C. et ah, J. Am. Chem. Soc. 2007, 129:4377 and O'Leary. B.M. et ah, J. Am. Chem. Soc. 2001, 123:11519. Trimethylester, 8 was prepared by reflupsilonxing 7 in methanol with sulfuric acid as a catalyst. Trihydrazide, 9 was prepared by dissolving the corresponding ester, 8 in ethanol with hydrazine and brief heating under reflux. The final uranyl ligand, Compoundl was prepared from 9 using Kemp's anhydride acid chloride in dry pyridine with DMAP. The uranyl ligand, Compound I was obtained in high purity by subliming off impurities (excess pyridinium chloride).Compound i  Compound I is most soluble in methanol or dimethylsulfoxide, and NMR studies were done in these solvents. Figures 4 and 5 show the H-TSIMR spectra of uranyl- free ligand in MeOD-d4 and 1H-NMR of uranyl ligand in MeOD-d4with uranyl acetate. The application of Compound I as an agent for uranyl ion sequestration was investigated through liquid-liquid extractions. An aqueous solution of uranyl nitrate (1.6 equivalents) in acetate buffer (pH=5.0) was stirred with chloroform solution of Compound 1 (1 equivalent) and the concentrations of uranium in each phase were determined before and after extraction with Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The extraction experiments were run at a series of uranium concentrations: 400 ppm, 40 ppm, and 4 ppm. At 400 ppm, Compound I extracted 55+5% of the aqueous uranyl ion into the organic phase and at 40 ppm 25+5% is extracted. At 4 ppm no uranium was extracted. The uranium can be recovered from the ligand by adding 0.5M HNO3. Compound I is highly selective for uranyl. The extraction of uranyl ion at 400 ppm was also carried out in the presence of six ions that dominate the chemistry of seawater: CT, Na+, Mg+2, Ca+2, K+ and SO4-2. With these ions present at seawater concentrations, Compound I showed no diminished function. Approximately, 55% of the uranyl ion was extracted into the organic phase.