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 1 M 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-4d1fb41ff68347a19abf0fc18d688d1a

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07745477B2