Ammonium Chloride → 4,5-Difluoro-N6-(2-fluoro-4-iodo-phenyl)-benzofuran-6,7-diamine

Participants

Reaction Steps

For scale up synthesis, a solution of (4,5-difluoro-7-nitro-benzofuran-6-yl)-(2-fluoro-4-iodo-phenyl)-amine (165 g) and NH4Cl in 2.5 L of THF and 2.5 L of water was cooled to between 0° C. and 5° C. Zinc dust was added (portionwise) at a temperature of less than 25° C. (exothermic during first half of addition) over 30 minutes. The addition of zinc dust resulted in a color change from yellow to dark purple and to pale yellow. Complete conversion was achieved with the addition of NH4Cl (50 g) and zinc (60 g), followed by vigorous stirring for 20 minutes and a further 1.5 hours. Purity was 89.5%. The suspension was filtered and rinsed with 1 L of water and 1.5 L of THF. The combined solution was concentrated to remove THF (87.7% purity). 3 L of EA was added with stirring for 30 minutes. The layers were separated; the EA layer was washed with 2 L of water twice and then dried of MgSO4. The EA was filtered and concentrated to dryness. The crude was used in the next step without further purification. 1H NMR (CDCl3, 400 MHz): δ 8.06 (d, 1H), 7.46 (dd, 1H), 7.40 (bs, 1H), 7.19 (d, 1H), 7.07 (d, 1H), 6.11 (t; 1H); 5.33 (bs, 1H).

Provenance & Evidence