tert-Butanol → N-ethoxycarbonyl-4-t-butyl-2-fluoroaniline

Participants

Reaction Conditions

Reaction Steps

2-Fluoro-N-ethoxycarbonylaniline (1.00 g, 5.46 mmol) prepared as described in Example 1 was dissolved in 77.6% sulfuric acid (5.00 g) to prepare a solution. t-Butyl alcohol (0.440 g, 6.01 mmol) was added dropwise to the solution under a nitrogen atmosphere over a period of 30 min while stirring and heating the solution at 70° C. After the completion of the dropwise addition, the reaction solution was vigorously stirred at the same temperature for one hr. Thereafter, t-butyl alcohol (0.440 g, 6.01 mmol) was again added dropwise thereto over a period of 30 min. After the completion of the dropwise addition, the reaction solution was vigorously stirred at the same temperature for one hr. t-Butyl alcohol (0.440 g, 6.01 mmol) was again added dropwise thereto over a period of 30 min. After the completion of the dropwise addition, the reaction solution was vigorously stirred at the same temperature for one hr. The reaction solution was cooled to room temperature. n-Hexane (10 mL) was then added to the cooled reaction solution to carry out extraction for separation of the mixture into a sulfuric acid layer and an organic layer. n-Hexane (10 mL) was again added to the sulfuric acid layer to carry out extraction for separation of an organic layer. The organic layers were combined, and the combined organic layer was washed with water and saturated brine in that order. The solvent was then removed from the organic layer by distillation to give 1.45 g of N-ethoxycarbonyl-4-t-butyl-2-fluoroaniline as an oily crude product (yield on weight basis 111%). The crude product was further subjected to separation and purification by column chromatography on silica gel to give 1.17 g of a mixture of 4-t-butyl-2-fluoro-N-ethoxycarbonylaniline with 5-t-butyl-2-fluoro-N-ethoxycarbonylaniline (yield 90%, 4-t-Bu: 5-t-Bu=82:18).

Provenance & Evidence