Sodium Pyrosulfite → 5,5'-(Hexafluoroisopropylidene)bis[1-phenyl-2-(3-ethynylphenyl)benzimidazole]

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Reaction Conditions

Reaction Steps

Compound VIII was synthesized from compounds (VI) and (V) as follows. A mixture of 2.00 g of sodium metabisulfite and 0.76 g (4.26 mmol) of 3-(trimethylsilylethynyl)benzaldehyde (VI) in 50 ml of 1:1 ethanol-water was deaerated with argon and heated at 75°-80° C. for 30 minutes. The yellow solution was then treated with a slurry of 1.00 g (1.94 mmol) of 2,2-bis(3-amino-4-anilinophenyl)hexafluoropropane (V) in 50 ml of ethanol. The mixture was heated at a gentle reflux (oil bath temperature about 100° C.) for 7 hours, cooled, diluted with 100 ml of 10% hydrochloric acid. The bright yellow solid was filtered, then washed with 50 ml of 10% hydrochloric acid, 50 ml of water and 50 ml of cold hexane. The powdery product (VII), after thorough drying, weighed 1.67 g (1.90 mmol, 97.8%) and showed characteristic trimethylsilylethynyl absorptions in its infrared spectrum.

Provenance & Evidence