Hydrazine, (2-fluoro-3-methylphenyl)- synthesis

Yield:1138036-49-3 63%

Reaction Conditions:

Stage #1: 2-fluoro-3-methyl-anilinewith hydrogenchloride;sodium nitrite in water at -20; for 1 h;
Stage #2: with tin(ll) chloride in water at -20 - 0; for 2 h;
Stage #3: with sodium hydroxide in water; pH=12;

Steps:

185 (2-fluoro-3-methylphenyl)hydrazine

Reference Example 185 (2-fluoro-3-methylphenyl)hydrazine To a solution of sodium nitrite (28.7 g) in water (100 mL) was added dropwise a solution of 2-fluoro-4-methylaniline (40 g) in concentrated hydrochloric acid (640 mL) at -20° C., and the mixture was stirred at the same temperature for 1 hr. A solution of tin(II) chloride (121 g) in concentrated hydrochloric acid (200 mL) was added dropwise at -20° C., and the mixture was stirred at 0° C. for 2 hr. The resulting solid was collected by filtration, and washed with water and hexane. The obtained solid was dissolved in water (500 mL), the solution was adjusted to pH 12 with 2 mol/L aqueous sodium hydroxide solution, and extracted twice with dichloromethane. The extract was dried over anhydrous sodium sulfate, and concentrated under reduced pressure to give the title compound as a white solid (28.4 g, yield 63%). ¹H-NMR (CDCl₃) δ: 2.24 (3H, d, J=2.4 Hz), 3.54 (2H, brs), 5.30 (1H, brs), 6.59-6.63 (1H, m), 6.89 (1H, dt, J=7.8, 2.0 Hz), 6.94-6.99 (1H, m).

References:

US2009/156642,2009,A1 Location in patent:Page/Page column 66