Reaction #607455

Reaction equation

HCl

2-Furoyl chloride

3,4-diaminoquinoline

dichloromethane

Water

→

2-Furyl-1H-Imidazo[4,5-c]quinoline

Solvents

pyridine

NaOH

Conditions

Workup

1. 1
   Otherto quench
2. 2
   Otherthe reaction
3. 3
   Otherthe solvent was evaporated under reduced pressure
4. 4
   Otherto afford an orange solid
5. 5
   TemperatureAfter cooling on ice the pH
6. 6
   OtherThe solid that precipitated
7. 7
   Filtrationwas filtered off
8. 8
   Washwashed with water and ether
9. 9
   ExtractionThen extracted with ethyl acetate (3 times 15 ml)
10. 10
    Washwashed with water (3 time 15 ml)
11. 11
    Dryingdried over MgSO4
12. 12
    OtherThe solvent was evaporated
13. 13
    Otherthe residue was dried

Procedure

2-Furoyl chloride (1.1 g, 0.8 ml, 8.1 mmol) in dry dichloromethane (15 ml) was added dropwise to a solution of to 3,4-diaminoquinoline 8 (1.0 g, 6.0 mmol) in dry pyridine (6.2 ml) under nitrogen. The solution was stirred for 2 hours at room temperature. Water (15 ml) was added to quench the reaction and the solvent was evaporated under reduced pressure to afford an orange solid. This crude solid in 2N NaOH (15 ml) was refluxed for 2 hours. After cooling on ice the pH was adjusted to 7 using concentrated HCl. The solid that precipitated was filtered off and washed with water and ether. Then extracted with ethyl acetate (3 times 15 ml) and washed with water (3 time 15 ml) and dried over MgSO4. The solvent was evaporated and the residue was dried. Eluent for column chromatography was 1-5% methanol in dichloromethane. Yield: 0.62 g (44%). Mp.: 236-238° C. 1H NMR (DMSO-d6): δ 6.74 (s, 1H, Ar); 7.35 (d, 1H, J=3.7 Hz, Ar); 7.69-7.73 (m, 2H, Ar); 7.83 (s, 1H, Ar); 8.09 (s, 1H, Ar); 8.46 (s, 1H, Ar); 9.09 (s, 1H, Ar). 13C NMR (DMSO-d6): δ 111.4, 112.6, 120.7, 121.8, 126.5, 127.2, 129.5, 138.2, 143.6, 144.3, 145.1, 147.2, 155.4.

Source