Potassium Hydroxide → 2-(4-Chloro-3-methoxyphenylthio)-4-fluorophenylacetic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of 4-chloro-3-methoxythiophenol (see Example 30) (36.2 g), 2-bromo-4-fluorophenylacetic acid (see the preceding Example) (39.6 g), potassium hydroxide (20 g) and dimethylformamide (250 ml) is heated to 100° C. while stirring until formation of a homogeneous solution. The greatest part of the dimethylformamide is distilled off under normal pressure, removing also the water arising by neutralization. Dimethylformamide (250 ml), anhydrous potassium carbonate (10 g) and copper (6 g) are added to the residue and the mixture is stirred for 14 hours in a bath heated to 170° C. The solvent is evaporated in vacuo, the residue dissolved in water, filtered and the filtrate made acidic by addition of hydrochloric acid. The separated oily acid is extracted with a large volume of warm benzene. The extract is then worked up, yielding 40 g of the crude 2-(4-chloro-3-methoxyphenylthio)-4-fluorophenylacetic acid which is crystallized from aqueous ethanol or cyclohexane. The pure compound melts at 118°-119° C.

Provenance & Evidence