Thionyl Chloride → 9H-Fluorene-9-carbonitrile

Participants

Reaction Steps

100 ml (1.37 mol) of thionyl chloride are added to 21.0 g (0.10 mol) of fluorene-9-carboxylic acid and the mixture is refluxed for about 90 minutes. The excess thionyl chloride is evaporated off on a vacuum rotary evaporator. The residue is taken up three times with about 50 ml of toluene each time and the mixture evaporated on a vacuum rotary evaporator. The oily residue is added in portions to a mixture of about 1 kg of ice and 240 ml of concentrated ammonia solution. The fluorene-9-carboxylic acid amide which has precipitated is filtered off, washed with water and dried under a high vacuum. The dried fluorene-9-carboxylic acid amide is then added to 160 ml (1.75 mol) of phosphorus oxychloride and the mixture is refluxed for about 2 hours. The reaction mixture is cooled and concentrated on a vacuum rotary evaporator. The residue is taken up in toluene and the mixture is washed with water. The organic phases are combined, dried over sodium sulfate and concentrated on a vacuum rotary evaporator. Crystallization of the residue from cyclohexane gives 12.4 g (65%) of 9-cyano-fluorene, melting point 152°-154° C. (compound (101), Table 1).

Provenance & Evidence