Thiourea → 5-Fluoro-2-methoxyaniline

Participants

Reaction Steps

A mixture of 2-chloro-3-(5-fluoro-2-methoxy-phenyl)-propionaldehyde (crude from above) and thiourea (29.2 g, 0.384 mol) in ethanol (400 mL) was heated to reflux for 15 hours. The solvent was removed and the residue was diluted with dichloromethane (300 mL), sodium hydroxide (10% aqueous solution, 150 mL) and water (200 mL). The aqueous phase was extracted twice with dichloromethane (150 mL). The combined organic layer was washed with water, a saturated aqueous solution of sodium chloride, dried over sodium sulfate, and evaporated to dryness. The crude product was recrystallized from a mixture of ethyl acetate and hexanes to give the pure product (6.5 g, 0.027 mol, 6.2% from 5-fluoro-2-methoxy-phenylamine). ESI-MS m/z calc. 238.1. found 239.2 (M+1)+ 1H NMR (CDCl3): δ 6.90-6.81 (m, 2H), 6.79-6.76 (m, 2H), 4.75 (br, 2H), 3.91 (s, 2H), 3.82 (s, 3H).

Provenance & Evidence