Reaktion #88685

Reaktionsgleichung

peracetic acid

n-BuLi

trimethoxy boron

tetramethylethylenediamine

triethylamine

acetic anhydride

5-Bromo-1,4-dimethyl-6-octyl-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine

→

1d

1,4-Dimethyl-6-octyl-2,3-dihydro-1H-pyrrolo[2,3-b]pyridin-5-yl acetate

Lösungsmittel

water

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionextracted with three 25-mL portions of EtOAc
2. 2
   WaschenThe combined organic layer was washed with brine
3. 3
   Trocknendried over anhydrous MgSO4
4. 4
   Filtrationfiltered
5. 5
   Einengenconcentrated under diminished pressure
6. 6
   workup.DISSOLUTIONThe resulting oil was dissolved in 10 mL of CH2Cl2 at 0° C.
7. 7
   workup.STIRRINGThe reaction was stirred at room temperature for 1 h
8. 8
   Sonstigequenched by the addition of 10 mL of sat aq. NH4Cl
9. 9
   ExtraktionThe solution was extracted with three 30-mL portions of EtOAc
10. 10
    WaschenThe combined organic layer was washed with brine
11. 11
    Trocknendried over anhydrous MgSO4
12. 12
    Filtrationfiltered
13. 13
    Einengenconcentrated under diminished pressure
14. 14
    SonstigeThe residue was purified via flash chromatography on a silica
15. 15
    WaschenStep gradient elution with 1:10→1:4 ethyl acetate-hexanes as eluent

Vorschrift

To a solution containing 202 mg (0.60 mmol) of 5-Bromo-1,4-dimethyl-6-octyl-2,3-dihydro-1H-pyrrolo[2,3-b]pyridine in 5 mL of THF was added 90 μL (69.7 mg, 0.60 mmol) of tetramethylethylenediamine (TMEDA) at −78° C. followed by 0.75 mL (1.20 mmol) of n-BuLi (1.6 M in hexanes). After 30 min, 147 μL (137 mg, 1.32 mmol) of trimethoxy boron was added and the resulting mixture was stirred for another 1 h. To the reaction mixture was added dropwise 277 μL (100 mg, 314 mg total solution mg, 1.32 mmol) of peracetic acid (32% wt) and the solution was then warmed to 0° C. The mixture was diluted by 20 mL of water and extracted with three 25-mL portions of EtOAc. The combined organic layer was washed with brine, dried over anhydrous MgSO4, filtered, and concentrated under diminished pressure. The resulting oil was dissolved in 10 mL of CH2Cl2 at 0° C., followed by the addition of 485 μL (352 mg, 3.48 mmol) of triethylamine, 6.1 mg (0.05 mmol) of DMAP and 164 μL (177 mg, 1.74 mmol) of acetic anhydride. The reaction was stirred at room temperature for 1 h and quenched by the addition of 10 mL of sat aq. NH4Cl. The solution was extracted with three 30-mL portions of EtOAc. The combined organic layer was washed with brine, dried over anhydrous MgSO4, filtered, and concentrated under diminished pressure. The residue was purified via flash chromatography on a silica: gel column (46×2.5 cm). Step gradient elution with 1:10→1:4 ethyl acetate-hexanes as eluent gave 1d as a yellow oil: yield 92 mg (48%); silica gel TLC Rf 0.22 (3:7 ethyl acetate-hexanes); 1H NMR (CDCl3) δ 0.76 (t, 2H, J=7.2 Hz), 1.12-1.22 (m, 10H), 1.55 (quint, 2H, J=8.0 Hz), 1.88 (s, 3H), 2.20 (s, 3H), 2.35 (t, 2H, J=8.0 Hz), 2.75 (t, 2H, J=8.4 Hz), 2.88 (s, 3H), 3.42 (t, 2H, J=8.4 Hz).

Quelle