Tin tetrachloride → 1-Methyl-9H-fluoren-9-one

Participants

Reaction Steps

A mixture of 1.32 g (6.2 mmol) of 3'-methyl-2-biphenylcarboxylic acid, 40 mL of CH2Cl2 and 0.70 mL (9.6 mmol) of SOCl2 was warmed to reflux for 2 h. The solution was cooled to room temperature and 1.10 mL (9.4 mmol) of SnCl4 was added dropwise with stirring. The dark brown homogenous mixture was stirred for 18 h, poured into 50 mL of cold saturated aqueous NaHCO3, and extracted with 2×50 mL of ether. The ether extracts were combined and washed with 30 mL of saturated NaHCO3 solution, 30 mL of H2 0 and 30 mL of brine, dried (MgSO4) and concentrated in vacuo. Chromatography over SiO2 (Biotage 40 S) using 1% EtOAc in hexanes provided 168 mg (16% yield) of 1-methyl-9-fluorenone (Ladd, D. L. et al., Synthesis and dopaminergic binding of 2-aryldopamine analogues: Phenethylamines, 3-benzazepines, and 9-(aminomethyl)fluorenes. J. Med. Chem. 1986, 29, 1904-1912).

Provenance & Evidence