Methanol → 2-Benzyl-5-chloro-4-methoxypyridazin-3(2H)-one

HRID 1865830Notes

Reaction equation

HRID 1865830 reaction equation
[CH2:1]([N:8]1[C:13](=[O:14])[C:12](Cl)=[C:11]([Cl:16])[CH:10]=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[O:17]1CCOC[CH2:18]1.C[O-].[Na+].CO>O>[CH2:1]([N:8]1[C:13](=[O:14])[C:12]([O:17][CH3:18])=[C:11]([Cl:16])[CH:10]=[N:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

6

Reactant 4

HCID 887MethanolHCID 312751,4-DioxaneHCID 7224382-Benzyl-4,5-dichloro-2,3-dihydropyridazin-3-oneHCID 10942334Sodium Methoxide

Product 1

HCID 135262132-Benzyl-5-chloro-4-methoxypyridazin-3(2H)-oneYield 93%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

To a round bottom flask was added 2-benzyl-4,5-dichloropyridazin-3(2H)-one (7.14 gm, 27.99 mmol), dioxane (125 ml, anhydrous). To the resulting reaction mixture was slowly added 25%/NaOMe in MeOH solution (6.98 ml, 30.51 mmol). The reaction was stirred at rt for 70 min. After this time, the reaction mixture was diluted with water (200 ml). The resulting solution was poured into a separatory funnel and extracted with CH2Cl2 (2×100 ml). The combined organic layers were washed with saturated aqueous NaCl (10 ml). The organic layer was then slurried with MgSO4 to remove excess water, filtered and concentrated to give the crude product. The crude product was purified using an automated column chromatography system (ISCO, 120 gm silica gel) eluting with 0-5% MeOH/CH2Cl2 to give product 2-benzyl-5-chloro-4-methoxypyridazin-3(2H)-one as colorless oil (6.5 gm, 93% yield). HPLC retention time (method A) 3.090 min; LCMS (M+H)=251.2.

Workup

  1. customTo the resulting reaction mixture
  2. additionThe resulting solution was poured into a separatory funnel
  3. extractionextracted with CH2Cl2 (2×100 ml)
  4. washThe combined organic layers were washed with saturated aqueous NaCl (10 ml)
  5. customto remove excess water
  6. filtrationfiltered
  7. concentrationconcentrated
  8. customto give the crude product
  9. customThe crude product was purified
  10. washeluting with 0-5% MeOH/CH2Cl2

Sources & evidence

ORD record
ord-1f1311cbeb194e76886e77382b05f688
Source dataset
uspto-grants-2009_12
Patent number
US07629342B2

Reaction notes

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