Sulfuric Acid → HCID 23043782, compound

Participants

Reaction Steps

Lithium diisopropylamide mono(tetrahydrofuran) (1.5M in cyclohexane; 3.6 ml) was added dropwise to a solution of 3,4-dihydro-1(2H)-dibenzothiophenone (1.0 g) in dry THF (30 ml) at -65°. The resultant solution was stirred at -65° for 1 h and 5-methyl-1-(triphenylmethyl)-1H-imidazole-4-carboxaldehyde (1.9 g) was then added. The reaction mixture was stirred for a further 1.5 h, whilst it was allowed to warm to 0°. The solution was quenched with acetic acid (6 ml) and the resultant suspension was treated with water (10 ml) and p-toluenesulphonic acid (10.2 g). The reaction mixture was heated at reflux for 17 h, added cautiously to 8% aqueous sodium bicarbonate (300 ml), and extracted with dichloromethane (2×120 ml). The combined organic extracts were dried and evaporated to give an oil which was heated at reflux in a mixture of trifluoroacetic acid (60 ml) and concentrated sulphuric acid (0.3 ml) for 40 min. The reaction mixture was concentrated in vacuo to ca. 10 ml, added cautiously to 8% aqueous sodium bicarbonate (300 ml) and the resultant suspension was extracted with dichloromethane (2×120 ml). The combined organic extracts were dried and evaporated to give a foam which was purified by FCC eluting with System A (100:5:0.5) to give the title compound (648 mg) as a solid, m.p. 220°-223°.

Provenance & Evidence