Pyridine → HCID 21265377, compound

Participants

Reaction Conditions

Reaction Steps

120 g of thionyl chloride was added to 100 g of 4-bromobenzoic acid and the mixture was heated at 90° C. while stirring for 6 hours. After the reaction, an excess amount of thionyl chloride was removed by evaporation. 85 g of bromobenzoic acid chloride was obtained at a distillation temperature range of 190°-200° C. by vacuum distillation at about 20 mmHg. A solution prepared from 50 g of 3,4-difluorophenol, 150 ml of dimethylformamide, and 31 g of pyridine was added dropwise to the bromobenzoic acid chloride over about one hour while stirring at a temperature below 30° C. The mixture was then heated to 70° C. and stirred for 10 hours, and poured into a 10-fold amount of water to produce crystals. The crystals were collected by filtration, washed with dilute HCl and then water, dried in vacuum at 40° C., and recrystallized from ethyl acetate to obtain 50 g of 3,4-difluorophenyl 4-bromobenzoate. To this were added 25 g of 4-n-propylphenylacetylene, 0.11 g of bis(triphenylphosphine)palladium(II) chloride, 0.12 g of copper iodide, 0.96 g of triphenylphosphine, and 320 ml of triethylamine, followed by stirring for 10 hours while heating at 90° C. After the reaction, the reaction product was poured into a 10-fold amount of water to produce crystals. The crystals were collected by filtration, washed with water, dried in vacuum at 40° C., and recrystallized from a mixed solvent of ethyl acetate and methanol to obtain 43 g of 3,4-difluorophenyl 4-[2-(4-propylphenyl)ethynyl]benzoate of the following formula. ##STR9##

Provenance & Evidence