O-Cresol → HCID 19387417, compound

Participants

Reaction Steps

4-Bromoanisole (46.7 g) was added dropwise to a stirred mixture of magnesium (6.0 g) in dry THF (250 mL). When all the magnesium had dissolved, 9-fluorene (40.0 g) in THF (400 mL) was added dropwise. The mixture was then stirred at room temperature for 3 hours and quenched with saturated ammonium chloride solution. The excess solvent was evaporated in vacuo and the residue extracted with ethyl acetate. The organic layers were dried (MgSO4), filtered, evaporated and recrystallized from hexane/ether to give 9-hydroxy-9-(4-methoxyphenyl)fluorene as a solid (48.2 g) M.P. 91°-93° C. This trityl alcohol (3.2 g) and o-cresol (1.8 g) were dissolved in acetic acid (25 mL) and concentrated H2SO4) (0.5 mL) was added dropwise. A deep red color developed rapidly and the reaction mixture decolorized after 30 seconds. After five minutes, the mixture was poured into water, neutralized with NaOH solution, and extracted with ethyl acetate. The organic layers were dried (MgSO4), filtered, evaporated in vacuo to give 9-(4-methoxyphenyl)-9-(3-methyl-4-hydroxyphenyl)fluorene (4.0 g) as an oil, which was used in the next step without further purification. Ethanethiol (3.7 g) was added dropwise to a stirred suspension of sodium hydride (2.3 g, 60% in mineral oil) in dry DMF (20mL). After the hydrogen bubbling had ceased, the above-mentioned oil was added and the mixture refluxed for 2 hours under nitrogen. The excess solvent was evaporated in vacuo and the residue extracted with ethyl acetate. The organic layers were dried (MgSO4), filtered, evaporated in vacuo and the residue recrystallized from chloroform-hexane to give the title compound (2.5 g) as a solid. M.P. 186°-188° C.

Provenance & Evidence