Quinoline → Methyl 5-ethenyl-2-hydroxybenzoate

Reaction equation

[C:1]([C:3]1[CH:4]=[CH:5][C:6]([OH:13])=[C:7]([CH:12]=1)[C:8]([O:10][CH3:11])=[O:9])#[CH:2].N1C2C(=CC=CC=2)C=CC=1>C(OCC)C.[Pd]>[CH:1]([C:3]1[CH:4]=[CH:5][C:6]([OH:13])=[C:7]([CH:12]=1)[C:8]([O:10][CH3:11])=[O:9])=[CH2:2]

Participants

Procedure

Methyl 5-ethynyl-2-hydroxybenzoate (8 g, 45.4 mmol), prepared according to Example 1b, was dissolved in a mixture of diethyl ether and light petroleum (200+200 ml) in a hydrogenation flask. Quinoline (1.7 ml) and palladium on CaCO3, poisoned with Pb (Lindlar catalyst; 200 mg) were added, and the flask was attached to an atmospheric pressure hydrogenation apparatus. The mixture was stirred for 2 h at room temperature, by then the calculated amount of hydrogen had been consumed. The catalyst was filtered off and the solution was evaporated to dryness. The product was purified by flash column chromatograpy on silica, using toluene as an eluent. A nearly quantitative yield was obtained.