Reaction #2146708

Reaction equation

diisopropylazodicarboxylate

1,3-propanediol mono-p-toluenesulfonate

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

triphenylphosphine

→

6-methoxy-2-[4′-(3″-p-toluenesulfonyloxypropoxy)phenyl]imidazo[1,2-a]pyridine

Yield 45.1%

Solvents

N,N-dimethylformamide

tetrahydrofuran

Conditions

Workup

1. 1
   workup.DISSOLUTIONto completely dissolve the contents
2. 2
   Concentrationthe reaction solution was concentrated
3. 3
   OtherThe resulting crude product was purified by flash silica gel column chromatography (elution solvent: chloroform/ethyl acetate=19/1)
4. 4
   Otherfurther purified by recycle preparative HPLC (HPLC apparatus
5. 5
   Othermobile phase: chloroform), and further purified again by flash silica gel column chromatography (elution solvent: hexane/ethyl acetate=35/65)

Procedure

To a solution of 554 mg (corresponding to 2.40 mmol) of 1,3-propanediol mono-p-toluenesulfonate in 10 mL of tetrahydrofuran, 260 mg (corresponding to 1.08 mmol) of 2-(4′-hydroxyphenyl)-6-methoxyimidazo[1,2-a]pyridine and 636 mg (corresponding to 2.42 mmol) of triphenylphosphine were added. Further, 5 mL of N,N-dimethylformamide was added thereto to completely dissolve the contents. To the reaction mixture, 0.48 mL (corresponding to 2.42 mmol) of diisopropylazodicarboxylate was added. After the resulting mixture was stirred at room temperature for 23 hours, the reaction solution was concentrated. The resulting crude product was purified by flash silica gel column chromatography (elution solvent: chloroform/ethyl acetate=19/1), further purified by recycle preparative HPLC (HPLC apparatus: LC-908 (under trade name: manufactured by Japan Analytical Industry Co., Ltd.); column: two of JAIGEL 2H (under trade name; manufactured by Japan Analytical Industry Co., Ltd.) connected together; mobile phase: chloroform), and further purified again by flash silica gel column chromatography (elution solvent: hexane/ethyl acetate=35/65) to obtain 220 mg (corresponding to 0.487 mmol) of 6-methoxy-2-[4′-(3″-p-toluenesulfonyloxypropoxy)phenyl]imidazo[1,2-a]pyridine (FIG. 1, Step 7).

Source