Reaktion #794425

Reaktionsgleichung

Diphenylphosphoryl azide

2-Chloro-5-fluoronicotinic acid

tert-butanol

triethylamine

→

tert-butyl (2-chloro-5-fluoropyridin-3-yl)carbamate

Ausbeute 50.4%

Lösungsmittel

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter 2 hours the reaction was cooled
2. 2
   Einengenconcentrated under reduced pressure
3. 3
   SonstigeThe residue was partitioned between water (100 mL), saturated sodium bicarbonate (70 mL) and ethyl acetate (300 mL)
4. 4
   TrocknenThe organic was dried with magnesium sulfate
5. 5
   Sonstigeevaporated to dryness under reduced pressure
6. 6
   SonstigePurification

Vorschrift

2-Chloro-5-fluoronicotinic acid (7.03 g, 40.0 mmol) was dissolved in a mixture of toluene (100 mL), tert-butanol (20 ml, 209 mmol), and triethylamine (6.8 ml, 48.9 mmol). Diphenylphosphoryl azide (9 ml, 41.8 mmol) was added slowly and the reaction heated at 90° C. After 2 hours the reaction was cooled and concentrated under reduced pressure. The residue was partitioned between water (100 mL), saturated sodium bicarbonate (70 mL) and ethyl acetate (300 mL). The organic was dried with magnesium sulfate and evaporated to dryness under reduced pressure. Purification using silica chromatography (hexane to ethyl acetate gradient) gave the desired tert-butyl (2-chloro-5-fluoropyridin-3-yl)carbamate (4.97 g, 20.15 mmol, 50.3% yield) as a thick oil.

Quelle