Reaction #2146693

Reaction equation

2-(4′-benzoyloxyphenyl)-6-methoxyimidazo[1,2-a]pyridine

boron tribromide

methanol

→

2-(4′-hydroxyphenyl)-6-hydroxyimidazo[1,2-a]pyridine

Yield 89.5%

Solvents

dichloromethane

Conditions

Workup

1. 1
   Otherto remove moisture
2. 2
   workup.DISSOLUTIONwas dissolved in 245 mL of chloroform
3. 3
   TemperatureAfter the temperature of the resulting solution was raised to room temperature
4. 4
   OtherAfter the completion of the reaction
5. 5
   Temperaturethe reaction solution was cooled with ice
6. 6
   workup.STIRRINGfurther stirred at room temperature for 3 hours
7. 7
   ConcentrationThe reaction mixture was then concentrated under reduced pressure
8. 8
   Otherto obtain slurry
9. 9
   Otherprecipitates
10. 10
    Filtrationwere filtered
11. 11
    Otherrecovered
12. 12
    OtherThe precipitates recovered
13. 13
    Washwere washed with chloroform
14. 14
    Otherdried under reduced pressure

Procedure

4.90 g (corresponding to 14.83 mmol) of 2-(4′-benzoyloxyphenyl)-6-methoxyimidazo[1,2-a]pyridine that was sufficiently dried to remove moisture was dissolved in 245 mL of chloroform and cooled down to −15° C. To this solution, a solution of 12.62 mL (corresponding to 133.48 mmol) of boron tribromide in 134 mL of dichloromethane was added dropwise. After the temperature of the resulting solution was raised to room temperature, the solution was stirred for 17 hours. After the completion of the reaction, the reaction solution was cooled with ice and supplemented with 668 mL of methanol, and further stirred at room temperature for 3 hours. The reaction mixture was then concentrated under reduced pressure. The resulting crude product was supplemented with 290 mL of chloroform and 29 mL of methanol to obtain slurry, and then precipitates were filtered and recovered. The precipitates recovered were washed with chloroform and then dried under reduced pressure, to obtain 3.00 g (corresponding to 13.28 mmol) of 2-(4′-hydroxyphenyl)-6-hydroxyimidazo[1,2-a]pyridine (FIG. 3, Step 6).

Source