Dichloromethane ethylacetate → 2-Chloro-5-fluoropyridin-4-amine

Participants

Reaction Steps

A mixture of 2-chloro-5-fluoro-4-nitropyridine-1-oxide (11, 1.3 g, 6.8 mmol) and 1.6 g of Raney nickel in 80 mL of anhydrous ethyl alcohol was hydrogenated at 40 psi in a Parr hydrogenation apparatus for 3 h when TLC showed that the starting material had disappeared and a new spot was detected (CH2Cl2/EtOAc, 4:1, v/v, Rf0.78 and 0.71, for the starting material and the product, respectively). The catalyst was removed by filtration and washed carefully with ethyl alcohol. The filtrate and washings were combined and evaporated in vacuo to give 0.9 g (91%) of product as an off-white solid. A small analytical sample was purified by recrystallization from hot water to afford white crystals: mp 110-111° C.; 1H NMR (CDCl3) δ4.50 (br s, 2 H, NH2, D2O exchangeable), 7.15 (d, 1 H, 3-H, J=6 Hz), 7.95 (d, 1H, 6-H, J=2 Hz). Analysis calculated for C5H4ClFN2: C, 40.97; H, 2.75; N, 19.12. Found: C, 41.18; H, 2.39; N, 18.89.

Provenance & Evidence