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ChemicalBook CAS DataBase List 2-Bromo-5-chloropyridine
40473-01-6

2-Bromo-5-chloropyridine synthesis

4synthesis methods
-

Yield:40473-01-6 93%

Reaction Conditions:

with hydrogen bromide;bromine;sodium nitrite in water at 0 - 10; for 1.5 h;

Steps:

2-Bromo-5-chloropyridine (3).
Bromine (26 ml, 0.52 mol)was added to a solution of 2-amino-5-chloropyridine (2)(25.6 g, 0.2 mol) in 48% HBr solution (100 ml, 1.2 mol),while maintaining the temperature at solution of sodium nitrite (32.4 g, 0.47 mol) in water(50 ml) was added over 1 h at the same temperature. Afterthe addition was complete, the reaction mixture was stirredfor additional 30 min and then treated with a solution ofNaOH (74.6 g, 1.86 mol) in water (100 ml) at such a ratethat the temperature did not exceed 20-25°C. The obtainedprecipitate was filtered off, washed with a saturatedsolution of NaHSO3 (~5 ml), several times with ice water(3×30 ml), and air-dried. Yield 35.6 g (93%), beige powder,mp 67-68° (hexane) (mp 68-69°10). Rf -0.4 (CHCl3).1H NMR spectrum (CDCl3), δ, ppm (J, Hz): 7.44 (1H, d,J = 8.4, H-3); 7.54 (1, dd, J = 8.4, J = 2.6, H-4); 8.35(1H, d, J = 2.6, H-6). 13C NMR spectrum (CDCl3), δ, ppm:128.7; 131.5; 138.1; 139.2; 148.6.

References:

Alekseyev, Roman S.;Amirova, Sabina R.;Terenin, Vladimir I. [Chemistry of Heterocyclic Compounds,2017,vol. 53,# 2,p. 196 - 206][Khim. Geterotsikl. Soedin.,2017,vol. 53,# 2,p. 196 - 206,11]

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