Reaktion #4446

Reaktionsgleichung

2-hydroxy-4-(4-pyridyl)thiazole

phosphorous oxychloride

→

2-chloro-4-(4-pyridyl)thiazole

Ausbeute 29.0%

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethen quenched
2. 2
   workup.ADDITIONby carefully pouring onto ice (4000 mL)
3. 3
   Extraktionextracted with methylene chloride (5×400 mL)
4. 4
   TrocknenThe combined extracts were dried over sodium sulfate
5. 5
   Einengenconcentrated
6. 6
   Sonstigechromatographed over silica gel (ethyl acetate as eluant)
7. 7
   SonstigeRecrystallization from ethyl acetate/hexane

Vorschrift

A mixture of 2-hydroxy-4-(4-pyridyl)thiazole (17.8 g, 0.10 mol) in phosphorous oxychloride (175 mL) was heated at 140° C. for 48 hours then quenched by carefully pouring onto ice (4000 mL). The resulting mixture was basified with 50% sodium hydroxide to pH 9 and extracted with methylene chloride (5×400 mL). The combined extracts were dried over sodium sulfate, concentrated, and chromatographed over silica gel (ethyl acetate as eluant). Recrystallization from ethyl acetate/hexane afforded 2-chloro-4-(4-pyridyl)thiazole (5.70 g, 29%). mp. 124°-125° C.

Quelle