Hydrochloric Acid → 2-Chloro-5-pyridinesulfonyl chloride

A solution of SO2 was prepared by adding thionyl chloride (24.2 mL) into stirring water (144 mL) containing copper (I) chloride (87.0 mg). The solution was then stirred at room temperature overnight. 5-Amino-2-chloropyridine (10.0 g, 77.8 mmol) was added into stirring conc. aq. HCl (80 mL) portionwise. The mixture was stirred until all solid dissolved and was then cooled to −5° C. Into the mixture was added dropwise a solution of sodium nitrite (5.9 g, 85.6 mmol) dissolved in 24 mL of water while the temperature was kept between −5° C. and 0° C. The resulting mixture was stirred for 30 minutes after the completion of the addition and then added dropwise into the aqueous solution of SO2. The temperature was kept below 0° C. during the addition. After the addition the mixture was stirred for 1 h below 0° C. and then filtered. The cake was washed with ice-cold water, dissolved in CH2Cl2, dried over Na2SO4 and concentrated to give 2-chloropyridine-5-sulfonyl chloride as a grey solid (13.6 g, 82%). 1H NMR (500 MHz, CDCl3): δ 9.04 (1H, d, J=2.4 Hz), 8.27 (1H, dd, J=8.5 Hz, J=2.6 Hz), 7.62 (1H, dd, J=8.5 Hz, J=0.4 Hz).

1. customA solution of SO2 was prepared
2. stirringThe mixture was stirred until all solid
3. dissolutiondissolved
4. temperaturewas then cooled to −5° C
5. customwas kept between −5° C. and 0° C
6. stirringThe resulting mixture was stirred for 30 minutes
7. additionafter the completion of the addition
8. additionadded dropwise into the aqueous solution of SO2
9. additionThe temperature was kept below 0° C. during the addition
10. additionAfter the addition the mixture
11. stirringwas stirred for 1 h below 0° C.
12. filtrationfiltered
13. washThe cake was washed with ice-cold water
14. dissolutiondissolved in CH2Cl2
15. dry with materialdried over Na2SO4
16. concentrationconcentrated

ORD record

ord-e9144e691a0747e49640599134704fbb

Source dataset

uspto-grants-2014_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08735414B2