[Cl:1][C:2]1[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][N:5]=[C:4]([NH2:11])[C:3]=1[C:12]#[C:13][Si](C)(C)C.[F-].[K+].C>CN(C=O)C>[Cl:1][C:2]1[C:7]([N+:8]([O-:10])=[O:9])=[CH:6][N:5]=[C:4]([NH2:11])[C:3]=1[C:12]#[CH:13]To a solution of 4-chloro-5-nitro-3-((trimethylsilyl)ethynyl)pyridin-2-amine (2.36 g, 8.76 mmol) in DMF (30 mL) was added potassium fluoride on alumina (40 wt %, 3.2 g, 22 mmol). The suspension was stirred at about ambient temperature for about 2 h. Activated charcoal (0.23 g) was added and the suspension was filtered though Celite®, washed with DMF (200 mL). The solvent was removed under reduced pressure and the residue was triturated with petroleum ether (50 mL, b.p. 30-60° C.). The solid was filtered, washed with petroleum ether (4×25 mL, b.p. 30-60° C.), and dried in vacuo to give 4-chloro-3-ethynyl-5-nitropyridin-2-amine (2.12 g, 89%) as a brown solid: LC/MS (Table 1, Method c) Rt=1.32 min; MS m/z 196 (M−H)−.
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