Iodine → 2',3'-Difluoro-4'-iodo-4-pentylbiphenyl

Participants

Reaction Conditions

Reaction Steps

2′,3′-Difluoro-4-pentylbiphenyl (612 g, 0.243 mol), and dry tetrahydrofurane (400 ml) were placed in 1 L flask equipped with mechanical stirrer, nitrogen inlet and outlet, pressure-equilibrated dropping funnel and thermometer. The reaction flask was flushed with nitrogen and minor flow was held during whole reaction time. The mixture was cooled down to −78° C. on the dry ice/acetone bath and then 2.5 mol/dm3 of n-butyllithium solution in hexane (100 ml 025 mol) was added dropwise, keeping the reaction temperature below −70° C. After addition of all n-butyllithium the mixture was stirred for additional 2 hours at −78° C. Next iodine solution in tetrahydrofurane (63.5 g, 0.25 mol) was added dropwise maintaining the temperature below −70° C. After addition of the iodine solution the cooling bath was removed and the mixture was stirred to reach the room temperature. Organic solvents were evaporated and the thick oily residue was diluted with hexane and treated with water solution of sodium sulfite to remove the remaining iodine. Phases were separated and hexane was evaporated. The residue was distilled under reduced pressure 1 mmHg collecting the fraction boiling at 174-175° C. The colourles liquid product 71 g was obtained with 78% of theor. yield.

Provenance & Evidence