Reaktion #43407

Reaktionsgleichung

2-chloro-5-fluoro-6-(methyloxy)-3-pyridinecarboxylic acid

toluene triethylamine tert-butanol

diphenylphosphoryl azide

sodium bicarbonate

→

1,1-Dimethylethyl [2-chloro-5-fluoro-6-(methyloxy)-3-pyridinyl]carbamate

Reaktionsbedingungen

Aufarbeitung

1. 1
   Extraktionthen extracted with ethyl acetate (3×500 ml)
2. 2
   TrocknenThe combined organic extracts were dried over magnesium sulphate
3. 3
   Sonstigeevaporated
4. 4
   SonstigeThe residue was chromatographed
5. 5
   Wascheneluting with 0-40% dichloromethane in petrol affording the product as a white solid (36.35 g, 83%)

Vorschrift

A mixture of 2-chloro-5-fluoro-6-(methyloxy)-3-pyridinecarboxylic acid (32.65 g, 159 mmol) in toluene/triethylamine/tert-butanol (300 ml/26.4 ml/75 ml) was treated with diphenylphosphoryl azide (37.7 ml, 174.8 mmol) and heated to 100° C. for 2 hours. The mixture was treated with saturated aqueous sodium bicarbonate solution (500 ml) then extracted with ethyl acetate (3×500 ml). The combined organic extracts were dried over magnesium sulphate and evaporated. The residue was chromatographed eluting with 0-40% dichloromethane in petrol affording the product as a white solid (36.35 g, 83%).

Quelle