2,5-Dibromopyridine

1. Description Off-White Crystals http://www.echemi.com/ http://www.echemi.com/ Basic Attributes CAS No：624-28-2 Molecular Formula ：C5H3Br2N Molecular Mass ：236.89 Exact Mass ：234.863205 PSA ：12.9 A^2 LogP ：2.6 EINECS ：210-839-6 InChIKeys ：ZHXUWDPHUQHFOV-UHFFFAOYSA-N H-bond Acceptor ：1 H-bond Donor ：0 SP3 ：0.00 RBN ：0 Characteristics Appearance ：Almost white or light beige to brown Crystalline Powder Density ：2.1±0.1 g/cm3 Melting Point ：92-95 °C(lit.) Bolling Point ：235 °C / 772mmHg Flash Point ：96.4±21.8 °C Refractive Index ：1.607 Solubility ：H2O: insoluble

2. Storage Condition ：Store below +30°C. BRN ：109099 Safety Information Hazard Class ：IRRITANT HS Code ：29333999 UN No. ：NONH for all modes of transport WGK_Germany ：3 Risk Code ：36/37/38-20/21/22 Safety Instructions ：26-37/39-36/37/39-36 Dangerous Mark ：Xi,Xn P Code ：P261-P305 + P351 + P338 Hazard Statements ：H315-H319-H335 Hazard Note ：Irritant Product Usage Organic synthesis, pharmaceutical intermediates. In the pharmaceutical industry, it is used to

3. synthesize diisopropyramine (propylpyramine pharmaceutical intermediates. Dimethyl sulfate is one of the important chemical raw materials. It is an important methylating agent. It is used in chemicals, medicine, pesticides, military industry, dyes, spices, rubber phosphate) for heart diseases. Used as Production Methods 2-Amino-5-bromopyridine (2; 13.0 g, 75.1 mmol) was added over 10 min to a cold (10 °C) aq 47percent HBr (37 mL, 0.33 mol). Br2 (11 mL, 0.21mol) was added, keeping the temperature below 10 °C. Then, a solution of NaNO2 (16.1 g, 0.19 mol) in H2O (19 mL) was added dropwise, maintaining the temperature at 0–5 °C. The reaction mixture was stirred for an additional 30 min, then treated with a solution of NaOH (28.0 g, 0.70 mol) in H2O (30 mL) at such a rate that the temperature did not exceed 20–25 °C. The mixture was extracted with Et2O (3 × 40 mL) and the combined organic layers were dried (Na2SO4). The solvent was evaporated under vacuum, the residue was suspended in hexane (10 mL), and the solid formed was collected by filtration to afford a pale brown powder; yield: 15.49 g (87percent); mp 94–95 °C (Lit.19mp 96 –97 °C); Rf = 0.55 (CHCl3). IR (KBr): 3411, 3022, 2924, 2852, 1549, 1437, 1356, 1090, 997 cm –1.1H NMR (CDCl3): δ = 7.39 (d, J = 8.4 Hz, 1 H, H-3), 7.67 (dd, J1 = 8.4 Hz,J2 = 2.5 Hz, 1 H, H-4), 8.45 (d, J = 2.4 Hz, 1 H, H-6). 13C NMR (CDCl3): δ = 120.1, 129.5, 140.4, 141.2, 151.3. MS (EI, 70 eV): m/z (percent) = 239 (36, [M (81Br, 81Br)]+), 237 (71, [M (79Br,81Br)]+), 235 (35, [M (79Br, 79Br)]+), 158 (85), 156 (85), 81 (57), 76 (78),50 (100).Anal. Calcd for C5H3Br2N: C, 25.35; H, 1.28; N, 5.91. Found: C, 25.46; H,1.13; N, 5.95.[00159] Scheme 1. Preparation of relevant pyri(mi)dyl halides A-H. Key: (a) NBS, NHTo a solution of 5-bromopyridin-2-amine (5.0 g, 28.9 mmol) in hydrogen bromide(50.0 mL, 46percent), sodium nitrite (15.0 g, 217.4 mmol) solution in water was slowlyadded at 0 °C. The resulting solution was stirred for 10 mm at the same temperature.Br2 (37.2 mL, 232.8 mmol) was slowly added to the reaction mixture at 0 °C andstirred for 15 mm at 0 °C. The reaction mixture was basified with sodium hydroxide and extracted with ethyl acetate, washed with sodium thiosulphate solution, water and brine solution. The organic layer was dried over anhydrous Na2SO4 and concentrated under vacuo. The product was purified by column chromatography toyield title compound (4.0 g, 58.0percent) white solid. LCMS: (M+H) = 237.9;1H NMR:(DMSO-d6, 300MHz) 6 8.57-8.58 (d, 1 H), 8.00- 8.04 (dd, 1 H), 7.64- 7.67(d, 1 H).To a solution of 5-bromopyridin-2-amine (5.0 g, 28.9 mmol) in hydrogen bromide (50.0 mL, 46percent), sodium nitrite (15.0 g, 217.4 mmol) solution in water was slowly added at 0 00 abd then stirred for 10 mm at the same temperature. To the reaction mixture Br2 (37.2 mL, 232.8 mmol) was slowly added at 0 00 and stirred for 15 mm at0 00. The reaction mixture was basified with sodium hydroxide and extracted with ethyl acetate, washed with sodium thiosulphate solution, water and brine solution. The organic layer was dried over anhydrous Na2SO4 and concentrated under vacuo. The product was purified by column chromatography to yield title compound (4.0 g, 58.0percent) white solid. LOMS: (M+H) = 237.9; 1H NMR: (DMSO-d6, 300MHz) 6 8.57-8.58 (d, 1 H), 8.00- 8.04 (dd, 1 H), 7.64- 7.67(d, 1 H).