Reaction #43578

Reaction equation

3-chloro-6-(methyloxy)-1,5-naphthyridin-4(1H)-one

water

phosphorous tribromide

water

potassium carbonate

3-chloro-6-(methyloxy)-1,5-naphthyridin-4-ol

→

desired compound

Yield 88.0%

8-bromo-7-chloro-2-(methyloxy)-1,5-naphthyridine

Yield 88.0%

Solvents

DMF

Conditions

Workup

1. 1
   Otherat 0° C.
2. 2
   Otherthe internal temperature below 20° C
3. 3
   workup.WAITat 25° C. for 1 h
4. 4
   OtherThe solid formed
5. 5
   Filtrationwas filtered off
6. 6
   Washwashed with water
7. 7
   Otherdried in the oven

Procedure

To a solution of 3-chloro-6-(methyloxy)-1,5-naphthyridin-4(1H)-one (3-chloro-6-(methyloxy)-1,5-naphthyridin-4-ol, for a synthesis see WO2004058144, Example 1(a) (5.1 g, 24.28 mmol) in DMF (50 ml) at 0° C. was added phosphorous tribromide dropwise (2.77 ml, 29.1 mmol) keeping the internal temperature below 20° C. The reaction mixture was then stirred at 10° C. for 0.5 h and then at 25° C. for 1 h. The mixture was then poured on 200 ml of water and the water basified to neutral pH with potassium carbonate. The solid formed was filtered off, washed with water and dried in the oven and then in the desiccator to afford the desired compound (5.8 g, 88%).

Source