ChemicalBook CAS DataBase List 5-Bromo-2-iodobenzoic acid

5-Bromo-2-iodobenzoic acid synthesis

5synthesis methods

Product Name:5-Bromo-2-iodobenzoic acid
CAS Number:21740-00-1
Molecular formula:C7H4BrIO2
Molecular Weight:326.91

5794-88-7

21740-00-1

General procedure for the synthesis of 5-bromo-2-iodobenzoic acid from 2-amino-5-bromobenzoic acid: a solution of 2-amino-5-bromobenzoic acid (3.9 g, 0.018 mol), sodium nitrite (NaNO2, 1.5 g, 0.022 mol) and sodium hydroxide (NaOH, 0.90 g, 0.023 mmol) in water (55 mL) was added dropwise to a stirred of a concentrated hydrochloric acid solution. The hydrochloric acid (HCl, 6.4 mL) in water (9 mL) solution was cooled at 0°C for 1.5 hours. After dropwise addition, stirring was continued for 30 minutes at 0°C. The formed diazonium salt suspension was added to a stirred solution of potassium iodide (KI, 4.5 g, 0.027 mol) and concentrated hydrochloric acid. A solution of sulfuric acid (H2SO4, 1.1 mL) in water (7.4 mL) was slowly added over 20 minutes at 35 to 40°C. The mixture was then heated to 90 °C and stirred for 30 min. Unreacted iodine was removed by steam distillation. The mixture was stirred and cooled. The crude product was filtered and washed with cold water, then dissolved in 40% aqueous sodium hydroxide. The polymer fraction was separated by decantation and the clarified solution was acidified with concentrated hydrochloric acid. The product was extracted with ether (Et2O). The extract was dried with anhydrous magnesium sulfate (MgSO4) and concentrated in vacuum. The residue was crystallized from a solvent mixture of methanol (MeOH) and water (H2O) (1:1, v/v) to give 5-bromo-2-iodobenzoic acid (3.56 g, 0.0109 mol, 60% yield) as a light yellow solid.

5794-88-7 Synthesis

5794-88-7
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21740-00-1
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Yield:21740-00-1 87%

Reaction Conditions:

Stage #1:5-Bromo-2-aminobenzoic acid with hydrogenchloride;sodium nitrite in water at 0 - 40; for 3 h;
Stage #2: with sulfuric acid;potassium iodide in water at 90; for 1.33333 h;

Steps:

1 Example 1. Synthesis of 2-iodo-5-bromobenzoic acid (2)
2-Amino-5-bromobenzoic acid (2.14 g, 10 mmol), NaNO2 (0.828 g, 12 mmol) and NaOH (0.55 g,11 mmol) was dissolved in 40 ml of water, stirred, cooled to 0 ° C in an ice bath, and 12 ml of a 6 mol/L hydrochloric acid solution was added dropwise thereto, and the mixture was dropped over 2 hours. After the completion of the dropwise addition of hydrochloric acid, the reaction system was continued at 0 ° C for 1 h, then the reaction system was heated to 35-40 ° C, and a solution of KI [(KI 2.5 g, 15 mmol), H 2 SO 4 (0.6 ml) and water (5 ml) was slowly added. ], 20min added. The reaction system was then heated to 90 ° C for 1 h. After the reaction,The reaction system was slowly cooled to room temperature to precipitate a large amount of solids.Filtered, washed with water to give a crude yellow product. The crude product was recrystallized from 50% ethanol to give a pale yellow solid, 2.87g.The yield was 87%.

References:

Jiangsu Engineering Polytechnic College;Feng Chengliang;Yao Wenjin;Yan Bin CN109678686, 2019, A Location in patent:Paragraph 0053-0055

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