HCID 13958724, compound → HCID 13958725, compound

Participants

Reaction Steps

4-(2-fluoro-5-nitrophenyl)-2,6-dimethylpyridine, 180 g, was divided into four equal portions and each portion was reduced separately as follows. A mixture containing 45 g of 4-(2-fluoro-5-nitrophenyl)-2,6-dimethylpyridine, 200 ml of acetic acid and 800 mg of platinum dioxide was catalytically hydrogenated until hydrogen uptake ceased, about 4 hours with little hydrogen uptake the last thirty minutes. The catalyst was filtered off, washed with 300 ml of water, and the filtrate made basic by adding aqueous ammonium hydroxide. The solution was cooled to yield a oily material which solidified. The solid was collected, washed with water and dried to yield the desired amine. The remaining three 45 g portions of 4-(2-fluoro-5-nitrophenyl)-2,6-dimethylpyridine were reduced in the same way and the combined amine products were dissolved in 600 ml of concentrated hydrochloric acid and heated on a steam bath with stirring for 4 and 1/2 hours and then treated with decolorizing charcoal and filtered. The filtrate was made basic by adding aqueous ammonia and the resulting mixture was chilled to yield an oil which crystallized. The crystalline material was collected, washed with water and dried in an oven to yield 164.9 g of gummy solid. The solid was dissolved in ether containing 5% methanol and the solution was filtered through silica gel to remove the gummy impurities. The ether-methanol solvent of the filtrate was distilled off in vacuo and the residue was recrystallized from ether-isopropyl alcohol to yield 80.9 g of 3-(2,6-dimethyl-4-pyridinyl)-4-fluorobenzeneamine, m.p. 142°-145° C. Concentration of the mother liquor yielded another 43.4 g of the product, m.p. 141°-144° C., thereby giving a total yield of 82%.

Provenance & Evidence