2-Fluoroaniline → 2-Fluoro-4-thiocyanatoaniline

A solution of bromine (3.02 g, 18.9 mmol) in sodium bromide-saturated methanol (11 mL) was added dropwise to a solution of 2-fluoroaniline (2.00 g, 18.0 mmol) and potassium thiocyanate (5.25 g, 54.0 mmol) in methanol (45 mL). The mixture was stirred for 0.5 hours, at room temperature, poured into water (300 mL) and made basic with solid Na2CO3. This aqueous mixture was extracted with Et2O (5×30 mL), then the combined Et2O extracts were washed with water (2×100 mL), saturated NaCl (100 mL), and dried (Na2SO4). Removal of the solvent under reduced pressure afforded a pale yellow liquid which was purified by dry flash column chromatography on silica (2.5% Et2O/hexanes as eluant) to give 4-amino-3-fluorophenyl thiocyanate as a white solid (1.60 g, 53%); m.p. 36-38° C. 1H NMR (400 MHz, CDCl3) δ 7.25 (dd, J=10.5, 2.2 Hz, 1 H), 7.18 (ddd, J=8.3, 2.2, 1.0 Hz, 1 H), 6.78 (dd, J=9.0, 8.3 Hz), 4.03 (br s, 2 H). Anal. Calcd for C7H5FN2S: C, 50.0; H, 3.0; N, 16.7. Found: C, 50.2; H, 3.0; N, 16.7. Step B: Preparation of 2-fluoro-4-methylthioaniline

1. extractionThis aqueous mixture was extracted with Et2O (5×30 mL)
2. washthe combined Et2O extracts were washed with water (2×100 mL), saturated NaCl (100 mL)
3. dry with materialdried (Na2SO4)
4. customRemoval of the solvent under reduced pressure
5. customafforded a pale yellow liquid which
6. customwas purified
7. customby dry flash column chromatography on silica (2.5% Et2O/hexanes as eluant)

ORD record

ord-ad8097639c7e468198a555accfa25ec1

Source dataset

uspto-grants-2005_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06891066B2