Ammonium Chloride → 2-Chloro-4-ethynylpyridine

Temperature

0 °C

To a solution of 2.389 g of 2-chloro-4-trimethylsilanylethynyl-pyridine (11.39 mmol) in THF (90 ml) were added 11.39 ml of a 1M TBAF solution in THF at −78° C. and the reaction mixture was stirred for 45 min at 0° C. Then saturated NH4Cl solution was added and the THF was removed under reduced pressure. The aqueous mixture was extracted with diethylether and the combined organic extracts were washed with water and brine, dried (Na2SO4), filtered and concentrated in vacuo. The remaining residue was purified by column chromatography (pentane/diethylether 100:0 to 4:1) to give 2-chloro-4-ethynyl-pyridine (1.427 g, 91%) as an off-white solid. 1H-NMR (CDCl3, 300 MHz): δ 3.36 (s, 1H), 7.27 (dd, J=5 and 1 Hz, 2H), 7.40 (br s, 1H), 8.37 (d, J=8 Hz, 2H).

1. customthe THF was removed under reduced pressure
2. extractionThe aqueous mixture was extracted with diethylether
3. washthe combined organic extracts were washed with water and brine
4. dry with materialdried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customThe remaining residue was purified by column chromatography (pentane/diethylether 100:0 to 4:1)

ORD record

ord-306d3973b3774497a593223746e565de

Source dataset

uspto-grants-2010_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07678818B2