Реакция #449800

Уравнение реакции

2-chloro-4-pyridinemethanol

NBS

K2CO3

NBS

Na2CO3

→

title compound

2-Chloro-4-pyridinecarboxaldehyde

Растворители

EtOAc

Условия реакции

Обработка

1. 1
   Температураwas refluxed for 3 h
2. 2
   Температураthe reaction was heated
3. 3
   Температураto reflux for an additional 3.5 h
4. 4
   Температураcooled
5. 5
   Фильтрацияfiltered through a pad of celite
6. 6
   Промывкаeluting with 0.5-4% CH3OH/CH2Cl2
7. 7
   workup.ADDITIONThe fractions containing product
8. 8
   Промывкаwashed successively with sat aq NaHCO3, 10% Na2S2O3, and brine
9. 9
   Сушкаdried (MgSO4)
10. 10
    Концентрированиеconcentrated in vacuo

Методика

A suspension of 2-chloro-4-pyridinemethanol (8.0 g, 55.9 mmol), NBS (14.9 g, 83.9 mmol), and K2CO3 (11.75 g, 97.1 mmol) in EtOAc was refluxed for 3 h. A second portion of NBS (14.9 g, 83.9 mmol) and Na2CO3 (12.0 g, 114 mmol) were added and the reaction was heated to reflux for an additional 3.5 h, cooled and filtered through a pad of celite. The filtrate, after concentrattion to a small volume, was subjected to flash chromatography eluting with 0.5-4% CH3OH/CH2Cl2. The fractions containing product were combined, washed successively with sat aq NaHCO3, 10% Na2S2O3, and brine, dried (MgSO4) and concentrated in vacuo to give the title compound as a light yellow solid; yield 5.3 g (67%). 1H NMR (CDCl3) δ10.06 (s, 1H), 8.66 (d, 1H, J=5.0 Hz), 7.76 (s, 1H), 7.66 (d, 1H, J=5.0 Hz).

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