4-Fluorobenzoic Acid → 4-Fluorobenzoyl chloride

Participants

Reaction Conditions

Reaction Steps

Separately, thionyl chloride (5 ml) is added to 4-fluorobenzoic acid (1.2 g) and the mixture is warmed at 60° C. for 3 hours, followed by distilling off excess thionyl chloride under reduced pressure to obtain 4-fluorobenzoyl chloride. To this chloride is added a solution of trans-4-(4'-heptylphenyl)cyclohexanol obtained above (2 g) in pyridine (2 ml) and toluene (50 ml), followed by vigorous shaking. The resulting reaction liquid is allowed to stand at room temperature overnight, followed by pouring it into water (50 ml) and further adding toluene (50 ml) to carry out extraction. The toluene layer is washed with 6N hydrochloric acid and then with 2N aqueous solution of sodium hydroxide, followed by washing with water until the layer becomes neutral, drying over anhydrous sodium sulfate and distilling off toluene under reduced pressure. The residual oily substance is recrystallized from ethanol to obtain the objective 4-fluorobenzoic acid trans-4-(4"-heptylphenyl)cyclohexyl ester. Yield: 2.6 g, 90.0%, C-Sm: 62.0°-62.3° C., Sm-N point: 78.4° C., N-I point: 102.1°-102.7° C.

Provenance & Evidence