Réaction #11321

Équation de réaction

ammonium persulphate

sulphuric acid

3,6-dichloropyridazine

ammonia

cyclobutane carboxylic acid

→

title compound

Rendement 82.0%

3,6-Dichloro-4-cyclobutylpyridazine

Rendement 82.0%

Solvants

water

water

water

Conditions de réaction

Traitement

1. 1
   Autrerose to approximately 85° C
2. 2
   workup.ADDITIONDuring the addition the product
3. 3
   Autreformed as a sticky precipitate
4. 4
   workup.ADDITIONUpon complete addition the reaction
5. 5
   Températureto cool to room temperature
6. 6
   Autrethe temperature below 10° C
7. 7
   ExtractionThe aqueous phase was extracted with dichloromethane (×3)
8. 8
   SéchageThe combined extracts were dried (MgSO4)
9. 9
   Filtrationfiltered
10. 10
    Autreevaporated

Mode opératoire

Concentrated sulphuric acid (53.6 ml, 1.0 mol) was added carefully to a stirred suspension of 3,6-dichloropyridazine (50.0 g, 0.34 mol) in water (1.25 l). This mixture was then heated to 70° C. (internal temperature) before the addition of cyclobutane carboxylic acid (35.3 ml, 0.37 mol). A solution of silver nitrate (11.4 g, 0.07 mol) in water (20 ml) was then added over approximately one minute. This caused the reaction mixture to become milky in appearance. A solution of ammonium persulphate (230 g, 1.0 mol) in water (0.63 l) was then added over 20–30 minutes. The internal temperature rose to approximately 85° C. During the addition the product formed as a sticky precipitate. Upon complete addition the reaction was stirred for an additional 5 minutes, then allowed to cool to room temperature. The mixture was then poured onto ice and basified with concentrated aqueous ammonia, with the addition of more ice as required to keep the temperature below 10° C. The aqueous phase was extracted with dichloromethane (×3). The combined extracts were dried (MgSO4), filtered and evaporated to give the title compound (55.7 g, 82%) as an oil. 1H nmr (CDCl3) indicated contamination with approximately 5% of the 4,5-dicyclobutyl compound. However, this material was used without further purification. Data for the title compound: 1H NMR (360 MHz, d6-DMSO) δ1.79–1.90 (1H, m), 2.00–2.09 (1H, m), 2.18–2.30 (2H, m), 2.33–2.40 (2H, m), 3.63–3.72 (1H, m), 7.95 (1H, s); MS (ES+) m/e 203 [MH]+, 205 [MH]+, 207 [MH]+.

Source