ChemicalBook CAS DataBase List 2,4-DICHLORO-5-NITROPYRIDINE

2,4-DICHLORO-5-NITROPYRIDINE synthesis

6synthesis methods

Product Name:2,4-DICHLORO-5-NITROPYRIDINE
CAS Number:4487-56-3
Molecular formula:C5H2Cl2N2O2
Molecular Weight:192.99

850663-54-6

4487-56-3

Step 3. Synthesis of 2,4-dichloro-5-nitropyridine: The product of step 2, 2-hydroxy-4-chloro-5-nitropyridine (40.0 g, 229 mmol), was suspended in toluene (300 mL), and phosphorus oxychloride (POCl3, 65 mL, 697 mmol) was added dropwise over a period of 10 min. Subsequently, the reaction mixture was heated to reflux and maintained for 6 hours. Upon completion of the reaction, the mixture was cooled to 60 °C and stirred continuously at this temperature overnight. The non-homogeneous reaction mixture was cooled to room temperature and subsequently concentrated under reduced pressure to remove the solvent. The residue was carefully adjusted to an alkaline pH with saturated aqueous potassium carbonate (K2CO3). extraction was carried out with ethyl acetate (EtOAc), the organic phases were combined and washed sequentially with water and saturated brine. The organic layer was dried over anhydrous sodium sulfate (Na2SO4), filtered and the filtrate was concentrated to give the crude product as an oil. Purification by silica gel column chromatography (eluent: hexane solution of 50% ethyl acetate) afforded the title compound 2,4-dichloro-5-nitropyridine (32.5 g, 74% yield) as an orange oil, which solidified to a solid on standing. Mass spectrometry (electrospray positive ion mode, ES+) showed the molecular ion peak m/e 194 [M+H]+.

7321-93-9 Synthesis

7321-93-9
175 suppliers
$20.00/100mg

4487-56-3
300 suppliers
$24.00/1g

Yield:4487-56-3 77%

Reaction Conditions:

with sulfuric acid;dihydrogen peroxide in water at 0 - 25; for 18 h;

Steps:

1 Synthesis of 2,4-dichloro-5-nitro-pyridine
Fuming H₂SO₄ (13 mL) was added dropwise to the stirred vessel. In a separate flask, concentrated H₂SO₄ was added to 4,6-dichloro-pyridin-3-ylamine (4.54 g, 27.9 mmol) and stirred until complete dissolution occurred. The amine solution was then added to the H₂O₂/fuming H₂SO₄ solution, dropwise. The reaction was allowed to warm to 25° C. over 18 h. The yellow solution was poured over ice and neutralized by the slow addition of solid NaHCO₃. The resultant aqueous solution was extracted three times with EtOAc and the combined organic layers were dried (Na₂SO₄), decanted and concentrated to afford 2,4-dichloro-5-nitro-pyridine as a yellow solid (4.13 g, 77%).