Reaction #61356

Reaction equation

water

aniline.HCl

NaOH

toluene

aniline

→

2-phenyl-4-hydroxyquinoline

Yield 20.0%

Conditions

Workup

1. 1
   Otherfor 16 h
2. 2
   ConcentrationThe solution was concentrated
3. 3
   Otherto afford a brown oil that
4. 4
   ExtractionThe aqueous suspension was extracted twice with ethyl acetate
5. 5
   Washwashed with brine
6. 6
   Dryingdried over MgSO4
7. 7
   Filtrationfiltered
8. 8
   Concentrationconcentrated
9. 9
   Otherchromatographed on silica gel
10. 10
    Washeluting with 3% MeOH in ethyl acetate

Procedure

This amide (250 mg, 1.53 mmol) was refluxed using a Dean-Stark apparatus with aniline (143 mg, 1.53 mmol) and aniline.HCl (10 mg, 0.08 mmol) in toluene (10 mL) for 16 h. The solution was concentrated to afford a brown oil that was mixed with polyphosphoric acid (2 g) and heated at 135° C. for 20 min. The reaction mixture was poured into water and adjusted to pH 8 with 5 M NaOH. The aqueous suspension was extracted twice with ethyl acetate. The organic layers were combined, washed with brine, dried over MgSO4, filtered and concentrated. The residue was flash chromatographed on silica gel, eluting with 3% MeOH in ethyl acetate, to give 2-phenyl-4-hydroxyquinoline (2), 67 mg, 20% yield.

Source