Ammonium Hydroxide → 4-Amino-3-chloro-2,5,6-trifluoro-pyridine

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Reaction Steps

This compound was prepared by a modification of the procedure of Chambers et al., J. Chem. Soc. 1964, 5634-5640. A mixture of 3-chloro-2,4,5,6-tetrafluoropyridine (1, 37.4 g, 201 mmol) and 150 mL of 28% ammonium hydroxide was stirred at room temperature for 5 h. The resulting white crystals were collected and carefully washed with ice water to give 2 as a white solid (35 g). The combined filtrate and washings were extracted with ether. The ether extract was dried (MgSO4), filtered and evaporated in vacuo to give additional 2 (1.3 g); total yield: 26.3 g (99%). The product was used directly for the next step in the reaction. A small sample was purified by silica gel column chromatography: mp 118-120° C. (Lit., Chambers et al., J. Chem. Soc. 1964, 5634-5640, mp 117-118° C.).

Provenance & Evidence